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11.1 Video editing
Sound and video editing
Sound and video editing can be carried out using a number of different packages.
In this book, we will be using Windows Movie Maker for video editing and
Audacity
®
for audio editing, but the principles of these exercises can be applied
using similar techniques in most editing packages. With Movie Maker, make
surethat you save the project at each stage throughout the chapter, as well as
saving/exporting in the required format. Throughout this chapter you will be
learning different editing techniques and the reasons why they are needed.
In this chapter you will learn about:
+ methods of video compression
+ the features found in video editing software
+ the features found in sound editing software
+ sampling rate and sampling resolution
In this chapter you will learn how to:
+ edit a video clip
+ edit a sound clip.
+ methods of sound compression
+ different editing techniques and the reasons
why they are needed.
For this chapter you will need these source files:
Q Activity_11c_audio.mp3
Q Activity_11e_audio_1.mp3
Q Activity_11e_audio_2.mp3
Q Balloon.mp4
Q Blue_Sky_Blues.mp3
Q EQ11-Bali1.mp4
Q EQ11-Bali2.mp4
Q EQ11-Bali3.mp4
Q EQ11-Bamboo.mp3
Q EQ11-Voice.mp3
Q Fish_Eagle.jpg
Q Fish_Eagle.mp4
Q Lake_Naivasha.mp4
Q Nurse_Shark.png
Q Shark.mov
Q Swim_through.mov
Q Task_11e_audio.mp3
Q Task_11j_audio_1.mp3
Q Task_11j_audio_2.mp3
Q Task_11n_audio.mp3
Q Task_11o_audio.mp3
Q Task_11p_audio.mp3
Q Voiceover_1.mp3
Q Voiceover_2.mp3
Q Voiceover_3.mp3
Q Voiceover_4.mp3
Q 11i.wav
Advice
Although Windows Movie Maker has been replaced by the Video Editor section
in the Microsoft Photos application, Video Editor does not have all the required
features you need to know and use.
11.1 Video editing
11.1.1 Frame size and aspect ratio
Before a video can be created or edited, the physical size of the completed
frames and their aspect ratio need to be determined. This will often depend
upon the audience and device/s that will view the completed video. The
11
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11
aspect ratio of each video frame is the relationship between the width and
height. There are two common ratios: 16:9 which is sometimes called
widescreen, and 4:3 which was originally called standard, although in
recent years 16:9 video has become more common than 4:3. These aspect
ratios determine the relationship between the number of pixels in the width
compared to the number of pixels in the height, so for a 4:3 ratio, the video
could be 400 pixels wide by 300 high, 1200 wide by 900 high, or 4000 wide
by 3000 wide and so on. The frame size, along with its aspect ratio, is set
when the video published/exported is saved.
Open Movie Maker and select the
Filetab, then from the top of the drop-down
menu, select the New project option. Select the Project tab, then in the Aspect
ratio section the option for 16:9 using the Widescreen icon.
Task 11a
Create a new video and set the image ratio to 16:9. Create title frames using the
image Fish_Eagle.jpg.
Add the text ‘Lake Naivasha, Kenya’ in a dark blue, 60 point, sans-serif font, so
that it looks like this:
Add an appropriate animation effect to place this text. Display this title for 8
seconds.
Save the video in 1920 x1080 format as Task_11a.mp4.
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Resize and crop a still image to an aspect ratio
Before creating the title frames, read the Task to find out what size the final
video will be. In this task the finished movie will be 1920 wide by 1080 pixels
high. Compare this to the image Fish_Eagle.jpg, which is 3764 pixels wide by
3092 pixels high. This image will need to be both resized and cropped to fit an
aspect ratio of 16:9.
Open your graphics/image editing package
(Adobe Photoshop has been used here, but most
packages will perform similar functions for this
Task). Select the image size using the
Image
tab, then from the drop-down menu select
ImageSize.
In the
Image size window, tick the box for
Constrain Proportions.
This
Constrain Proportions check box maintains the aspect
ratio of the image so that it does not become distorted.
Nowchange the Pixel Dimensions:, Width: to 1920. You
will see that the image height now becomes 1577 rather
thanthe 1080that we require. Click
.
To crop this image with accuracy, select the Image tab,
thenthe
Canvas Size option. Change the units from
centimetres into pixels using the drop-down menu.
Looking at the image provided we need to keep the eagle
which is placed in the bottom-right corner. In the
Anchor
box, click the mouse in the bottom-right corner. The
anchor will change to this.
Enter the new height of
1080 into the height box, then
click
. Awarning will be given, click on
and the image will be cropped. Resave
theimage using
File and Save As… and name the image
Fish_eagle1.jpg, so you do not overwrite the original
source file.
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11.1.2 Insert a still image
The reasons for inserting still images are similar to those for extracting still images.
You may have a particularly nice photograph which, if included in the video, would
enhance it greatly. You may have extracted a frame to edit it and now you want to
put it back. Open Movie Maker and using File
Explorer open the folder containing the Fish_
Eagle1.jpg image so that bothpackages are
visible on the screen at the same time. Drag
the image Fish_Eagle1.jpg from File Explorer
into the right half of the Movie Maker window
likethis.
To change the duration of this background,
click on the image, then on the
Edit tab.
In the
Adjust section, find Duration and
use the drop-down menu to set this to 8
seconds.
Advice
Always use the Duration to set timings as this is more accurate than manually
dragging the timer bar.
11.1.3 Create text-based slides
It is sometimes necessary to add text to videos. It is generally
accepted that adding text to videos engages the audience and
helps them retain the video content better. To add the title
text, click on the
Home tab, then in the Add section select
the icon for
Title. This will add a black title background in
front of the eagle image. Ignore this for now, and add the
text Lake Naivasha, Kenya into the centre of the window.
It may wrap onto two lines like this.
As you edit this the tab at the top changes to the
Format tab.
You can use this to set the Text duration to 8 seconds to match
the eagle image. Setthe Start time to 7:00s so that the title
text now overlays the eagle image. You will not be able to see
this text until you move the slider button toabout 10 seconds.
Click back on the text box, in the
Font section, click on the drop-down menu
for the Text Colour to select a dark blue colour (you may need to use More
Colours to find one dark enough).
Change the
Font size to 60 and make
sure a sans-serif font is selected. In the
Paragraph section, choose the icon to
left-align the text. Click on and drag
the text box into the top-left corner so
that it looks like the image in the Task
box. On the right side of the package,
click the mouse on the old title (it is
the black/grey rectangle below the
eagle image). With this black/grey
area selected, press the
<Delete> key
on the keyboard. The project looks
similar to this.
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11.1.4 Add animation effects
The final instruction in the Task before saving the movie is to ‘Add an appropriate
animation effect to place this text’. This instruction means that only the text is
animated, not the background image as well. Click on the text so that it is selected,
then from the
Format tab, in the Effects section, select any of the effects (except
the first one). Choose one that does not place the text over the eagle part of the
image and means that the text can be easily read by the audience in the
time it will be displayed. If details of your target audience are given,
make sure the font and animation are suitable for them.
Advice
Please note that some of the effects work when the text enters the
frame and some when it leaves. Make sure that the effect you choose
matches the question.
Play the video clip to make sure it matches the specifications in the
Task. The video needs to be saved in the required format, so from
the
File menu, select Save movie, then for the required resolution
(1920× 1080) select For high-definition display. In the Save
Movie window enter Task_11a.mp4 then click
.
Activity 11a
Create a new video and set the image
ratio to 4:3. Create title frames using
the image Nurse_Shark.png.
Add the text ‘Diving in Cozumel,
Mexico’ in a yellow, 48 point, serif font,
so that it looks like this:
Add an appropriate animation effect
to place this text. Display this title for
6seconds.
Save the video in 960 x 720 format as
Activity_11a.mp4.
11.1.5 Trim a video clip
Video clips can have the start or end of them removed. This process is called
trimming and can be completed with accuracy using the trim tool. Trimming and
cropping a video can serve similar purposes. They are both used to remove parts of
the video that are unwanted. The introduction to a video may be too long or boring
so needs to be shortened or trimmed. There may be some unwanted material
such as a person or something that has appeared in the background without you
realising. This will need to be cropped. Trimming can be used to bring video and
audio into synch if they are not already.
Task 11b
Open and examine the file Lake_Naivasha.mp4 in a video editing package.
Trim this clip so that it starts after 8 seconds and finishes 4.5 seconds later.
Remove all sound from this video clip.
Save the video in 1920 x1080 format as Naivasha2.mp4.
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Open Movie Maker and drag the file Lake_Naivasha.mp4 into the right-hand
side of the Movie Maker window. Select the
Edit tab. In the Editing section
left-click on the
Trim tool icon.
This opens the
Trim tab where precise values can be entered for the start
point and end point. Place in the
Start point box the value 8 and in the
End point box enter the value 12.5 (which is the start point value plus the
4.5 seconds for the clip). Click on the Save trim icon.
11.1.6 Remove sound from a video clip
Open the Edit tab and select the Video volume button. This will open a small
volume window. Drag the slider handle to the left end of the volume bar to mute
all sound within the clip.
Play the video clip to make sure it matches the specifications in the original
question. From the File menu select Save movie, then for the required
resolution (1920×1080) select For high-definition display. In the Save Movie
window enter Naivasha2.mp4 then click
.
Task 11c
Open and examine the file Lake_Naivasha.mp4 in a video editing package.
Trim this clip so that only the first 6.3 seconds remain. Remove all sound from
this video clip. Speed up this clip so that it runs at 1.5 times the playing speed.
Save the video in 1920 x1080 format as Naivasha1.mp4.
Reopen the file Lake_Naivasha.mp4 in Movie Maker. Trim the clip using the
method described above, with a Start point at 0 seconds and an End point at
6.3 seconds, then remove the sound from the clip.
It may be helpful to note that other video software use separate tracks for video
and sound, so sound can be removed by deleting the sound track in alternative
software.
11.1.7 Alter the speed of a video clip
To speed up this clip so that it runs at 1.5 times the playing speed, click on
the Edit tab, then in the Adjust section use the drop-down menu for Speed,
changing the speed from 1× to 1.5 ×. The length of the video clip will change
from 6.3 seconds to 4.2 seconds. Use the method described in Task 11b to save
the clip with the filename Naivasha1.mp4 and a resolution of 1920 × 1080.
11.1.8 Splice/join together video clips
To splice means to join two pieces of video together; it was a term used for
physically cutting and joining traditional film footage stored on a reel. To join
two elements of video in Movie Maker means to place one element after another
within your project.
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To start this Task, we need to create a new
project and splice together the files Task_11a.
mp4, Naivasha1.mp4 and then Naivasha2.
mp4, which is achieved by dragging each file
into the right portion of the screen using the
methods from Task 11a. When these clips have
been placed in the correct order it should look
similar to this.
Your editor may show more intermediate
framessimilar to this.
11.1.9 Extract a still image from a video clip
One reason for extracting a still image from a video clip is that a particular
frame of a video might make a wonderful photograph to put in a photograph
album. Another reason is that you might want to edit or add other graphics to
the image using a graphics package before reinserting it back into the video.
Slide the timing bar so that it is placed at the end of the Task11a.mp4 video
likethis.
Select the
Home tab, then the Snapshot icon. Give the snapshot a meaningful
filename, such as Snapshot_n2end.png. As this snapshot is saved, it is
automatically added to the end of the project with a duration of 7 seconds.
Clickon the additional frames that represent this image to select it, then from
the
Edit tab, change the duration to 10 seconds.
11.1.10 Add a caption/subtitle
Captions/subtitles are needed for many reasons. The people watching the video
may have a hearing impairment and so subtitles help them understand what is
being said. It may be that they are watching the video in a public place where
there is lots of background noise making it difficult to hear, such as a shopping
mall. They could be in a quiet public place, such as a doctor’s waiting room,
Task 11d
The purpose of the video is to advertise the spectacular bird species that can be
found at Lake Naivasha in Kenya. All stills and video clips were filmed by GBRvideo
at Lake Naivasha in Kenya in August 2019.
Create a new video clip saved in 1920 x1080 format as Task_11d.mp4.
Place the title frames stored in Task_11a.mp4 at the start, followed by
Naivasha1.mp4 then Naivasha2.mp4. Take an extract of the final frame of
Naivasha2.mp4 and use this as a background image for the caption frames,
which should appear for 10 seconds. Add caption frames to indicate that there
are over 400 species of birds seen in the rift valley and that Lake Naivasha
offers some of the best bird-viewing opportunities. Place, after the caption
frames, the video clip Fish_Eagle.mp4. Complete the video with appropriate
credits lasting 6 seconds.
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11
where if they switched on the audio it could be disruptive, annoying other people.
The viewers might not speak the same language as the people in the video and
so subtitles in different languages could be provided. People tend to be more
engaged with a video if the caption is reinforcing what the video is saying.
The text for the caption must give all of the information required by the Task,
which is that ‘there are over 400 species of birds seen in the rift valley and
that Lake Naivasha offers some of the best bird-viewing opportunities’. All of
this information must be included but do not copy it directly. Consider the
information and how you would like to present it. This is a long piece of text,
so perhaps two different sets of caption text can be used. Select caption text
that is easy to read and appropriate for the audience, using short easy-to-read
sentences without complex punctuation or words which may be difficult to read
or understand, for example:
Lake Naivasha sits in the Great Rift Valley. It is home to over 400 species of birds.
Lake Naivasha offers some of the best bird-watching in the world.
To add a caption over the top of the still image, slide the timing bar so that it is
at the start of the caption frames like this.
From the
Home tab select the Caption icon. Replace the text ‘Enter text
here’ with the first part of the caption. You are now in the Format tab.
In the Adjust section, use the lower drop-down menu to set a duration of
5seconds. Unless animation effects are required by the Task, do not use
them. Check that the text is appropriately placed within the frames so that the
background image is still clearly visible. Select a font style that is easily read
by the audience and if no styles are specified, select an appropriate font for
the content of the presentation and the audience, for example if it is for young
children, a clear font (not cursive or with too many/long serifs) in a large
easily read font size would be appropriate. For this caption, dragging the text
box up the frame gives better contrast and is more easily readable. Move the
timing bar to the end of this caption and add a second 5-second caption using
the second example line above.
If subtitles are required, use caption text to create a subtitle. You can have text
that appears to be a subtitle and other text that appears to be a caption on the
screen at the same time. To do this change the font style/size/enhancements of
the subtitle text so that it is clear that it is different from the caption text.
11.1.11 Create credits
Credits are used to inform viewers about the people involved in the creation of
the video. They are a way of acknowledging the help, support and contributions
made by people in the making of the video. Feature-length productions usually
have both opening and closing credits. Opening credits are shown at the
beginning and closing credits at the end. In short videos, all credits are placed
at the end of the video. Their purpose is to inform viewers who was involved in
the production of the video, for example filming, editing, sound and so on, and
usually include production details like filming location, date and so on.
For this video, the information has been embedded into the Task and must also
include your details as you have edited the video. The credits need to include:
Filmed by: GBRvideo
Location: Lake Naivasha, Kenya
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11.1 Video editing
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Advice
If projects are to be edited at a later date, save the project in .wlmp format and
then export in the format (such as MP4) that is instructed in the Task. Often you
must submit files in the specified format. Files submitted as Movie Maker projects
(.wlmp files) only contain links to the files, not the files themselves, so anyone
viewing the file cannot see the content.
Activity 11b
The purpose of the video is to advertise the spectacular diving that can be found in
Cozumel, Mexico. All stills and video clips were filmed by GBRvideo at Palancar Reef,
Cozumel, Mexico, August 2004.
Create a new video clip saved in 960 x720 format as Activity_11b.mp4 using this
storyboard.
0 secs: Title frames from Activity_11a.mp4.
6 secs: Swim_through.mov trimmed so that it starts at 15 seconds and the clip
is 51 seconds long.
57 secs: Take an extract of the final frame of your clip from Swim_through.
mov and use this as a background image for the caption frames, which should
be placed for 8 seconds. Add caption frames to indicate Jacques Cousteau once
called Cozumel ‘the most spectacular diving site in the world’.
65 secs: Shark.mov trimmed so that only the first 6 seconds remain.
71 secs: Take an extract of the final frame of your clip from Shark.mov and
use this as a background image for the credits, which should be placed for
10 seconds. Add appropriate credits to match the brief to this background.
Export your video in .mp4 format with the filename Activity_11b.mp4.
Date filmed: August 2019
Edited by: <Your name>
Advice
Ensure that your name, centre number and candidate number are included in the
credits.
To add these credits to the video, place the timing bar at the end
of the video and from the Home tab, in the Add section, click on
the
Credits icon. The tab will change to the Format tab. Replace
the text [Enter name here] with the text from thelist above
including replacing the text <Your name> with your name. The
credits will, as the default setting, scroll up thescreen and be set
on a black background like this, but other types of animation effect
can be chosen from the
Effects section. If an image or clip is also
used behind the background credits, ensure that the credits are
formatted and positioned so that they have good contrast and can
be easily read. From the
Format tab, in the Adjust section, use the
drop-down menu to adjust the duration to 6 seconds.
Play the video clip to make sure it matches the specifications in the original
question. Use the method described in Task 11b to save the clip with the
filename Task_11d.mp4 and a resolution of 1920 × 1080. Save the project
as a .wlmp file.
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Locate the folder containing
the file Task_11e_audio.mp3
and double-click on this file.
This will now beincluded
as part of yourproject and
will showasa green ribbon
likethis.
Test the audio to ensure
thatit plays when the video
isplayed.
Use the method described
in Task 11b to save the
clip with the filename
Task_11e.mp4 and a
resolution of 1920 × 1080.
Save the project in .wlmp
format.
11.1.12 Add sound to a video clip
Adding sound may be necessary if the creator of a video wishes to get an
emotional response from the viewer as well as explaining the details of the video
sequence. A human voice used in narration can convey the emotion or mood of
the video’s contents. Music can be added, whether it be the strings of a violin
suggesting sadness, the rousing sound of a song for a happy
ending, or the calming effect required when observing sea life.
Sound effects are needed when action needs emphasising, for
example, explosions, speeding cars, and people walking, to name
just a few.
Open the file Task_11d.mp4 in Movie Maker. As the audio clip
is to be added after 5 seconds, move the timing bar to exactly
5seconds from the start. From the
Home tab, select the
Add music icon which opens a drop-down menu like this.
This icon is used to add any audio clip, including music or narration.
Select the option for
Add music at the current point....
Task 11e
Open your video clip saved as Task _11d.mp4.
Add the soundtrack Task_11e_audio.mp3 to this video so that it starts after
5seconds.
Save the video clip in 1920 x 1080 format as Task_11e.mp4.
Export this movie in the same format into .wmv, .mov and .avi file formats.
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11.1.13 Export in different file formats
Not all devices and platforms are able to play videos in all formats, which
means some videos are incompatible with particular devices or platforms.
Videos may also need to be converted to reduce their file size to allow them
to be attached to an email or to reduce storage space. The compression
algorithm that particular formats use can be different and so the file format
may need changing.
To export the movie into .wmv (Windows Media Video file) format, from
the
File tab, select Save movie, then For high definition display. Enter in
the
File name: box the text Task_11e.wmv and use the drop-down menu
inthe
Save as type: box to select Windows Media Video File (*.wmv).
Click
.
To change the movie into .mov and .avi formats requires the use of a video
conversion program.
Advice
There are many programs for video conversion available, but make sure that you
are familiar with the use of one that is downloaded to your computer, for when you
are unable to access an online converter.
Activity 11c
Open your video clip saved in Activity 11b.
Add the soundtrack Activity_11c_audio.mp3 to this video so that it starts after
3 seconds. Save the video clip in 960 x 720 format as Activity_11c.mp4.
Export this movie in the same format into .wmv, .mov and .avi file formats.
Task 11f
Open your video clip saved as Task _11e.mp4.
Publish/save this movie with the filename Task _11f so that it can be viewed on
YouTube, on an Android phone with medium resolution, and burnt on a DVD.
Prism has been chosen for this Task, but there are many similar free-to-use
products available. Open this application and select the Add File(s) icon.
Double-click on the file Task_11e.mp4 and the file is added to the List of
Filesto Convert
. Select in the Output Format: box .avi, then click Convert.
To export this file into .mov format, return to the Output Format: drop-down
list and change the setting to .mov, then click the Convert button.
11.1.14 Compress video to different resolutions
So far, we have created videos with high resolution in 16:9 and 4:3 format.
We can use both Movie Maker and the video conversion software to save our
projects in different resolutions for different media.
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Open the project for Task 11e in Movie Maker. Publishing the movie to
web-specific requirements for video-sharing services on the internet like
YouTube can be completed by using the
File tab, Publish movie and selecting
YouTube. Select a resolution that will allow your movie to be uploaded to the
video-sharing service. For this example, to create a smaller file size, we will
choose a smaller image resolution, for example
1280 × 720. You will then need
to sign into your account to use this service. This element of the process will not
be assessed.
To save it in a format suitable for an Android phone, use the
File tab, then Save
movie and scroll down the drop-down list to the right to find and select the
option for Android phone (medium) which will save the video in 960 × 720
format. Enter the filename Task_11f_android.mp4 then click
.
To burn this video onto a DVD, we need a copy of Express Burn software
installed which runs alongside Prism. Open the video conversion software,
in this case Prism, and use the method described in Task 11e to add the file
Task_11e.mp4. Select
File from the toolbar and Burn files as DVD Video
Disk with Express Burn. Type in the text Lake Naivasha for the Disc label:
then click on
. A DVD writer with a blank DVD is required for this
to function.
11.1.15 Add fading effects: part 1
Sometimes it is necessary to indicate that a period of time has passed between
two scenes in a video. This can be achieved by fading out the first scene and
fading in to the next scene. It is sometimes used because the video creator
wishes to ease the audience’s emotions after a troubling scene. A more
significant end or beginning requires a slower fade with more time spent on a
blank/black frame.
If the creator wishes to show that only a few hours or minutes have passed
between scenes, a fairly quick fade can be used. A longer fade can be used when
the time interval between scenes is days/months/years.
Fading effects in Movie Maker can be created using transitions which are used to
link two parts of a video together with a smooth change, rather than one frame
moving to a very different frame and giving a very jerky effect as the video plays.
They can also be created using pre-set fades too, and from black or white (as we
will see later in this chapter).
Advice
If you hover the mouse over any part of the right side of the
Movie Maker window, the information about the element is
shown like this.
Task 11g
Open the project saved in Task 11e. Add a 2-second
transition between the clips Naivasha1 and
Naivasha2. Save the video clip in 1920 x1080 format
as Task_11g.mp4.
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Open the project saved in Task 11e in
MovieMaker. To add the transition, click
on the video Naivasha2.mp4 (between
12.4 and16.8 seconds) to select it within
the package.
Select the
Animations tab. In the
Transitions section are a number of
different transitions that can be applied,
although only the first few transitions
can beseen at the moment. There are
many more different transitions listed in
the scrolling menu, including disolves,
wipes, reveals and so on. Select the type
of transition thatwouldbe appropriate; a
very small dissolve for this transition has
been chosenhere.
The question requires a
2-second transition; the
default for this transition
is1.5 seconds.
Use the drop-down menu for
Duration: to change this value to 2.00. Play the
video and check that it gives a smooth transition between the two video clips. Use
the method described in Task 11b to save the clip with the filename Task_11g.mp4
and a resolution of 1920×1080. Save the project in .wlmp format.
11.1.16 Add pan and zoom effects
The pan and zoom effects are applied to a video or image to make it slowly
zoom in on a focal point of an image or pan across an image. In Movie Maker
there are three effects: pan only, which moves from one focal point to another;
zoom in, which removes some or all of the outside of an image; and zoom out,
which moves from a focal point to a wider angle view.
Activity 11d
Open the project that you saved in Activity 11b.
Add 1-second transitions between the title frames and swim_through.mov and
between the caption and shark.mov. Save the video clip in 960x 720 format as
Activity_11d.mp4.
Task 11h
Create a new video and set the image ratio to 16:9. Place the video balloon.mp4
at the start. Use pan and zoom to remove the hand and camera from the video
clip. Take a snapshot of the final frame and zoom in on the balloons.
Save the video in 1920 x1080 format as Task_11h.mp4.
Create a new Movie Maker project with a 16:9 aspect ratio.
Drag the file balloon.mp4 into the project. Watch the video
clip to see where the hand and camera appear. Select the
Animations tab. In the Pan and zoom section, use this
button to show all pan and zoom options.
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We need to zoom in to remove the left edge of the image. This
means we need to select an option from the Zoom in section.
Select the option for
Zoom in right
to remove the left edge of the clip. Several other zoom in options
would also remove this. Move the timing bar to the end of
the clip and select the
Home tab followed by the Snapshot
button to make a still image of the final frame of the zoomed
video clip.Select this clip and again select the Animations
tab, then in the Pan and zoom section, select the option for
Zoom in left. Play the video again to see this effect. Use the
method describedin Task 11b to save the clip with the filename
Task_11h.mp4 and a resolution of 1920 ×1080. Save the project
in .wlmp format.
11.1.17 Use filters and colour correction
Movie Maker has limited facilities for
colour filters and colour correction,
but these are available from the
Visual
Effects tab which contains a range of
different filters to apply to the image/
clip. Different effects can be applied to
the same still image or clip by cutting
and splicing these into smaller segments
and applying the effect to one segment.
For example a 1-second portion of a
video can be blurred by splitting the
video clip into three and applying the
blur filter to the 1-second segment.
Multiple effects can be applied to the
same clip using the
Multiple effects...
button at the bottom. The black and
white effects can be used to give the film clip an old-fashioned look (using sepia)
or by turning the video into a black and white version, or to make something
look colder using the cyan tone.
Open the project saved in Task 11e in Movie
Maker. Hold down
<Ctrl> and press <A> to select
all elements of the video. From the
Visual Effects
tab, in the Effects section for Black and white,
select the option for Cyan tone.
Click on the still image and again from the Effects
section select the drop-down menu, then the
Multiple effects button. This opens the Add or
Remove Effects window.
Task 11i
Open the project saved in Task 11h. Give the savannah the appearance of being
a cold place using a filter. Add an effect to ensure that the frames fade to black
for the credits. Add credits to the clip on a black background and display this
for 7 seconds. Save the video in 1920 x 1080 format as Task_11i.mp4.
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11.1.18 Add fading effects: part 2
From the Available effects: list, double-
click on the option for Fade out to black
to add this to the Displayed effects: list,
then click
. Place the timing
bar at the end of the snapshot and from
the Home tab select the Credits button.
Add your name to these credits. Use the
method described in Task 11b to save the
clip with the filename Task_11i.mp4
and a resolutionof1920× 1080. Save the
projectin.wlmp format. It now looks
likethis.
11.1.19 Video compression
There are two types of file compression used for both video and audio files. These
are lossless compression and lossy compression. Lossless compression does not lose
any data when the compression takes place. Lossy compression loses data.
There are many factors that affect the file size of a finished video. One is the
number of pixels used for the product. The size of a Standard Definition file
(SD) is often 720×480 pixels, which is 345 600 pixels per frame, whereas for a
High Definition file (HD) it is 1920 × 1080 pixels, which is 2 073 600 pixels per
frame, and a 4K Ultra High Definition file (UHD) is 3840 ×2160 pixels, which
is 8 294 400 pixels per frame. The higher the definition of the file, the higher the
number of pixels per frame required to store and stream it. A second factor is the
length of the video. Generally, the shorter the video, the less storage space and
streaming time are required. Another factor is the number of frames per second.
Much of the video produced is set at 30 frames per second (fps) and if the number
of frames per second is reduced from 30 fps to 15 fps the video will require half
of the original storage capacity and time taken to stream it. Other factors can also
affect the compression; these include whether progressive frames or interlaced
frames are used, how frequently the key frames occur, and the audio sample rate
and render quality, but these factors are beyond the scope of this book.
The video is stored in a container, like .mp4, .wmv, .mov, .avi and so on, and
each of these holds the compressed data in a different form. The software
used to display the video (it may be video-playing software, a browser or even
software within a games console) must recognise the container holding the
video and understand the
codec used to encode the video within the container.
The same codec must be used in the software to decode the video. If the codec
is not present in the software (for example it has not been added to your browser
as an add-in), then the video within the container will not play.
The word ‘codec’ is short for coder/decoder and is a program that knows how
to handle video (and/or audio) when stored in a particular format. It is used to
compress and decompress the data, often for/from data transmission.
Data might be compressed so that it can be shown on a phone with a small
display, such as 426 × 240 pixels. If this compressed video was displayed on a
UHD monitor or television, it would be very pixelated and almost unviewable.
It is therefore critical that the correct container and compression method is
selected when data is saved. Unless storage space and bandwidth for streaming
are very limited, always select a lossless format.
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11.2 Audio editing
11.2.1 Import a new track
Open Audacity. There are two methods to open a file: the first is to open
File Explorer in the folder showing the source files. Drag the file Task_11j_
audio_1.mp3 from Explorer into Audacity. This track has now been imported
into the audio editor. The second method is to use the File tab, then Open
before selecting this file and clicking
.
11.2.2 Normalise a sound clip including removing any DC offset
If an audio file has been converted from
analogue to digital values using a faulty
audio device, it may appear to have an
offsetwaveform like this
rather than like this,which is centred along
the 0 line.
To remove the
DC offset (which can
causeclicks, distortion and loss of audio
volume), select the
Effect tab, then from
thedrop-down menu select Normalize….
The Normalize window will open;
make sure the
Remove DC offset box
isticked,then click
. In this case
itwill change the waveforms of both left
andrightaudio channels to this.
This has also had the effect of amplifying
both channels.
11.2.3 Add a track to a sound clip
To add a new track to an existing clip, either drag
the new clip into the editor or from the File tab
select Import, then from the drop-down menu
selectAudio. Select the file Task_11j_audio_2.mp3,
then click
. Both audio tracks are sitting
alongside each other like this.
Task 11j
Open the track Task_11j_audio_1.mp3 in your audio editing package.
Normalise this track to remove any DC offset. Add Task_11j_audio_2.mp3 as a
new track, clipped so that only the first 19.1 seconds remain, to start before the
first clip. Trim the whole clip so that only the first 45 seconds remain.
Add a 3-second fade-in to the clip and a 5-second fade-out. Change the clip
from stereo into mono. Save the audio clip as Task _11j.mp3.
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11.2.4 Trim to remove unwanted material
Trimming an audio clip is necessary at times to remove unwanted material such
as a sudden noise accidentally recorded. It is also needed if the length of a track
has to be reduced. This could be due to only a certain length being required or
to save storage space on a medium. Having
added the second audio clip to the editor we
now need to remove the end of the clip so
that only 19.1 seconds remain. Click on the
lower audio file to make sure it is selected.
Set the timer using the
Audio Position
counter to 19.100 seconds.
This is much more precise than using the
timing bar. Set the Start of Selection
counter to the same value.
Set the
End of Selection counter to just
after this audio clip finishes; I have chosen
48seconds.
To remove the end of these tracks,
click on the Cut icon.
11.2.5 Splice/join together
There are a number of reasons why we might want to splice/join together
two sound clips. One could be to make two recordings flow uninterrupted
into one another. Another could be that we want to combine the best
parts from several recorded performances of the same act.
As the audio clip from the previous section will be the first clip in our
completed clip, we need to change the order of the clips. Move to the
lower clip and select the button for
Open menu…, like this.
From the drop-down menu select Move Track Up. The clips are now
reordered.
To splice the clips together, select all tracks using the
Select tab followed by
All (or <CtrlA>). Move to the Tracks tab to open the drop-down menu.
Select Align Tracks to open another menu, then Align End to End. Select
the
Tracks tab again followed by Mix, then from the sub-menu select Mix
and Render. This will merge the two clips into a single stereo clip.
Use the methods shown in Section 11.2.4 to trim the clip so that only
the first 45 seconds remain.
Advice
Each time you perform any action in the sound editing section, listen
on your headphones to the changes that you have made, to ensure
that you have completed each task without distortion.
11.2.6 Fade in and fade out
Fade-in and fade-out are two very necessary features of sound editing.
We may need to fade in and/or fade out a sound clip. This could be because a
piece of music does not contain an obvious ending. The beginning/end of an
audio clip may not be smooth so a fade-in/fade-out is necessary. There may need
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to be a clear section of silence before the audio starts. A fade-in may be needed if
it is necessary to soften the sound of the drum and/or percussion instruments.
Use the
Start of Selection and End of
Selection counters to highlight the first
3 seconds of the clip from the previous
section to create the fade-in. Select the
Effect tab, then from the drop-down
menu select Fade In. The waveform at
thestart of the clip changes from this
to this.
You can see how the waveforms have
been compressed (making the audio
quieter) in the second version.
Use the
Start of Selection and End of
Selection counters to highlight the last
5seconds of the clip to create the fade-out. Select the
Effecttab, then from the drop-down menu select Fade Out.
The waveform at the end of the clip changes from this
to this.
11.2.7 Change from stereo to mono
This compresses all the audio data held in the two tracks
(stereophonic with left and right channels) within the clip
into a single monophonic track. Select the clip, then from
the
Tracks tab drop-down menu select Mix and from the
sub-menu select Mix Stereo Down to Mono. The two
trackshave now been mixed down into a single mono track.
11.2.8 Amplif y
Because one track was originally quieter than the other, mixing down
the two tracks leaves an imbalance in the final volumes. The section from
19.1seconds to the end of the track is quieter than the first, as can be seen
by the much shorter waveforms, so this section is highlighted and adjusted
from the
Effect tab using Amplify. Audacity calculates the amount of
amplification required (to match the loudest portion of the clip) so from the
Amplify window, make sure that the Allow clipping box is unchecked, then
click
. This amplify effect will be used later in the chapter to add
voiceovers to a clip.
Save the project using the
File tab, then Save Project, then from the
sub-menu select Save Project As which gives a warning message that this
will not generate a playable audio file but an editable project that can only
be opened in Audacity.
Advice
Ensure you use the correct formats when you export audio files.
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11.2.9 Export in .mp3 format
You must export this clip into .mp3 format
so that it can be played on a range of
devices.From the
File tab select Export,
thenfrom thesub-menu select
Export
asMP3
. This opens the Export Audio
window.
Enter the
File name:, in this case Task_11j.mp3,
and ensure that the Save as type: box
contains MP3 Files. In the Format Options
section, tick the check box for Force export
to mono.
Do not edit the other sections in the
Format
Options. We will study some of these later
in the chapter. Click
. Enter in the
Edit Metadata Tags window details of the
originator(s) and track(s), such as title, year
and so on; original works are being used to
create this clip, but both artists have allowed
their work to be used for commercial purposes as long as credit is given to
them. Do not use other artists’ material unless it is copyright-free or you have
permission to use it from the originator.
Click
to save this work.
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11.2.10 Change the pitch
Open the file Task_11j.mp3 in Audacity. This clip
is made up of two separate clips which were created
in different keys, so we are going to change the
pitch of one part of the clip from the key of C into
the key of F to match the other part of the clip.
Highlight the first 19 seconds of the clip. From the
Effect tab select Change Pitch…. This opens the
Change Pitch window. In this instance, Audacity
has suggested that we make the changes that we
want to make to satisfy the Task.
11.2.11 Alter the speed
Select all of the audio clip using <CtrlA>. From the
Effect tab, select Change Speed…. This opens the
Change Speed window. Set the Speed Multiplier
box to 1.400.
Click
to change the clip speed. The length
ofthe audio clip changes from about 45seconds to
about32seconds. Save the Audacityproject file and
export the audioclip as Task_11k.mp3.
11.2.12 Apply noise reduction
Noise reduction helps to reduce background sounds that are constantly present
like hiss, hum, buzzing or fan noise, but cannot remove irregular background
noise such as clicks, noise from traffic or from an audience.
Activity 11f
Open the track Activity_11e.mp3 in your audio editing package. Change the
pitch of the first 30.6 seconds of the clip from the key of C sharp/D flat into the
key of F sharp/G flat. Slow down the whole clip so that it plays at 0.9 times the
speed. Save the audio clip as Activity_11f.mp3.
Task 11k
Open the track Task_11j.mp3 in your audio editing package. Change the pitch
of the first 19 seconds of the clip from the key of C into the key of F. Speed up
the whole clip so that it plays at 1.4 times the speed. Save the audio clip as
Task_11k.mp3.
Activity 11e
Open the track Activity_11e_audio_1.mp3 in your audio editing package. Clip this
track so that only the section between 1 minute 17.2 seconds and the end of the
clip remains. Normalise this track to remove any DC offset. Add Activity_11e_
audio_2.mp3 as a new track, clipped so that only the first 30.6 seconds remain,
to start before the existing clip. Save the audio clip as Activity_11e.mp3.
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Task 11l
Open the track Voiceover_1.mp3 in your audio editing package. Remove the
background noise from this clip. Trim the clip so that it is 4 seconds long.
Save the audio clip as Task _11l.mp3.
Open the file Voiceover_1.mp3 in
Audacity. To reduce the background
noise in the clip, we must select an
area of the clip that contains only the
background noise, for example between
3.3 seconds and 8.09 seconds like this.
Then from the
Effect tab, select
Noise Reduction…. The Noise
Reduction window opens. In the Step1
section, click on
.
Select all of theaudio file with
<CtrlA>, then from the Effect tab,
select
Noise Reduction… again. In
the Step 2 section, there are settings
that you can change, but the default
settings are almost always good
enough for cleaning up the types of
background noise we mentioned earlier
(like hiss, hum, buzzing or fan noise).
These settings have probably been
set to around a 12-
decibel reduction
with a sensitivity of 6 and 3 bands of
frequency smoothing like this.
Click
to include the
noisereduction. Trim the clip so
that it is 4seconds long, save the
projectand export the clip as
Task_11l.mp3.
11.2.13 Add or adjust reverberation
Reverb is an effect whereby the sound produced by a musical instrument or
amplifier is made to echo slightly (reverberate). The effect sounds like an echo
that you would get when speaking or playing an instrument in a cavern or an
empty room. By altering the size of the cavern or room, the amount of echo
changes. Reverb can be used to give extra ‘depth’ to a voice.
Task 11m
Open the track Voiceover_2.mp3 in your audio editing package. Add a small
amount of reverb to the track between 4 and 6 seconds. Add increased treble
to the track between 8 and 11.8 seconds. Add increased bass to the track from
11.8 to 15 seconds. Save the audio clip as Task _11m.mp3.
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Open the file Voiceover_2.mp3 in Audacity. To add
reverb to only the part of the track between 4 and 6
seconds, we must highlight only that section of the
track. From the
Effect tab, select Reverb… to open
the
Reverb window which appears like this.
Click
to listen to the results of the
reverbusing your headphones.
To edit the reverb so that only a small amount is
added (to make the voice sound slightly richer/
deeper) but with not as much echo, you can change
the settings for the
Room Size to 60% and the
Reverberance to 40% (they may already be set to
this). Listen again using
Preview. You can edit each
setting a small amount until you get the effect that
you require.
11.2.14 Apply equalisation
Equalisation, often referred to as EQ, means boosting or attenuating (reducing)
the levels of different frequencies in a signal. In its simplest form, it is a process
whereby you can boost the bass (low frequencies) or treble (high frequencies) in
an audio clip, but the sounds are equalised to get exactly the overall effect that
is required. Equalisation can also be used to place filters to reduce certain noise
frequencies (either high or low frequencies) on audio clips.
To add increased treble to the track between 8 and 11.8 seconds, first select this
section of the audio clip. Versions of Audacity from 2.3.3 onwards do not have an
equalisation section, but this can be completed using the
Effect tab, then Graphic
EQ…. You are presented with a series of sliders, the bass (low) frequencies are on
the left and the treble (high frequencies)
are on the right. We can increase all the
treble frequencies by 10 decibels and for the
upper mid-range frequencies we can show a
gradual increase like this.
Click
to set this equalisation.
Listen to the clip and you can adjust the
volume of each frequency range to make
the voice sound as you want it.
To increase the bass to the track from 11.8
to 15 seconds, first select this section of
the audio clip, then move the sliders to set
the EQ like this.
Again, listen to the clip and you can adjust
the volume of each frequency range to make
the voice sound as you want it. Save the
project and export the clip as Task_11m.mp3.
Activity 11g
Open the track Blue_Sky_Blues.mp3 in your audio editing package.
Add lots of reverb to the track between 20 and 30 seconds. Add increased bass
to the track from 40 to 50 seconds. Add increased treble to the track between
1 minute and 1 minute 10 seconds. Save the audio clip as Activity_11g.mp3.
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11.2.15 Apply a high-pass filter
A high-pass filter is used in sound systems to allow high frequencies to pass
through while filtering or cutting low frequencies. A physical high-pass filter
(device) was originally connected to smaller speakers (tweeters) to remove the
bass elements being sent to these speakers. High-pass filters are also included
as optional settings in some top-end microphones when they are used for
recording in offices or warehouses. They can filter out the low frequency noises
from devices like fans or air-conditioning units. In terms of editing existing
audio, we can use software to replace the hardware filters when dealing with
audio clips.
Always apply the noise reduction
filter before applying a high-pass
filter. In Audacity the high-pass filter
attenuates (reduces the effect of) the
lower frequencies. You decide where
the attenuation starts and the number
of decibels per octave used for that
attenuation. It is similar to setting a
graphic equaliser like this.
Open the file Task_11n_audio.mp3 in Audacity. Select an area of background
noise from 40 to 50 seconds (even though the sound in this part of the clip may
be barely audible) and from the
Effect tab select Noise Reduction… then click
. Select all of the audio file with <CtrlA>, then from the Effect
tab, select Noise Reduction… again in the Step 2 section and click
to set the noise reduction.
Highlight the clip between 10 and 20 seconds and from the
Effect tab select
High-Pass Filter…, then click
. You can see from the waveform and
hear on this clip that this has a dramatic effect on the audio clip, because much
of the music was previously low-frequency bass. Save the project and export the
clip as Task11n_high.mp3.
11.2.16 Apply a low-pass filter
We do not need to reapply noise reduction when using a low-pass filter, because
these functions remove some of the same frequencies. Start a new project and
reopen the file Task_11n_audio.mp3 in Audacity. Highlight the clip between
10 and 20 seconds and from the Effect tab select Low-Pass Filter… and
click
. You can see from the waveform and hear on this clip that this
Task 11n
Open the track Task_11n_audio.mp3 in your audio editing package. Apply a
high-pass filter to the clip between 10 and 20 seconds. Save the audio clip as
Task_11n_high.mp3.
Reopen the track Task_11n_audio.mp3 in your audio editing package. Apply
a low-pass filter to the clip between 10 and 20 seconds. Save the audio clip as
Task_11n_low.mp3.
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11.2.17 Apply echo and decay
Echo copies the same sound and replays it after a given delay time, usually with
fewer decibels than the original sound. The process of losing decibels each time
the sound is repeated is called ‘decay’. Creative use of echo can make a single
sound/note into much more.
Open the file Task_11o_audio.mp3 in
Audacity. Highlight the clip between
10 and 20 seconds. From the
Effect
tab, select Echo… to open the Echo
window. Set the Delay time: at 0.5
seconds and the Decay factor: at 0.8
like this.
Click
. You can see from the
waveform and hear on this clip that
each echo has added to the original sound
in thissection, like this.
Task 11o
Open the track Task_11o_audio.mp3 in your audio editing package. Apply echo
with a 0.5 second time delay and a decay factor of 0.8 to the clip between 10
and 20 seconds. Save the audio clip as Task_11o.mp3.
Task 11p
Open the track Task_11p_audio.mp3 in your audio editing package. Add the
track Voiceover_3.mp3 so that it starts at 10 seconds and is clearly audible.
Save the audio clip as Task_11p.mp3.
Export this clip into .wav, .m4a, and .aac formats.
Export this clip as Task11p_Blu-ray.mp3 for use in a Blu-ray Disc
TM
player.
Activity 11h
Open the file you saved as Activity_11g.mp3 in your audio editing package.
Apply a high-pass filter to the clip between 1 minute 20 seconds and 1 minute
30 seconds and apply a low-pass filter to the clip between 1 minute 40 seconds
and 1 minute and 50 seconds. Save the audio clip as Activity_11h.mp3.
has hada lesser effect than the high-pass filter, because there are fewer high-
frequency notes in this clip, although the audible effect is still noticeable. Save
the project and export the clip as Task11n_low.mp3.
11.2.18 Overdub to include a voiceover
Overdubbing is usually carried out by adding extra instruments to a music track
to give it a richer, fuller sound. It means putting other tracks on to existing
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11
tracks. It is often needed when a voiceover is needed to explain the contents of
the existing sound track.
Open the file Task_11p_audio.mp3 in Audacity. Add the second clip
Voiceover3.mp3 so that both clips are present. Click on the track Voiceover_3
and move the timer bar to exactly
11 seconds. From the Tracks tab, select
Align Tracks, then from the sub-menu select Start to Cursor/Selection Start.
Although the voiceover can be heard, it
would be better to reduce the volume
(number of decibels) of the instrumental
clip during this period. Highlight the
instrumental (track without the voiceover)
track between 10 seconds and 21 seconds.
From the
Effect tab, select Amplify.
In the Amplify window, change the
Amplification (dB): setting to -6 (which
will reduce the volume of this section by
6decibels) like this.
Click
to reduce the volume of this section of the track. To mix the
tracks together, use <CtrlA> to select all tracks. Move to the Tracks tab to
open the drop-down menu. Select Mix, then from the sub-menu select Mix
and Render to New Track. Save your project. Now remove the original
instrumental and voiceover clips from the project and save again with a new
filename. Export the clip as Task_11p.mp3.
11.2.19 Export in different file formats
We have already exported this clip into .mp3 format (which is the most
commonly used digital format). Both .mp3 and .m4a (which is an unprotected
file extension for a file with advanced audio coding
[.aac]) are in lossy format, where sound quality is not
always as good as the original recording. Both .aac and
.m4a (which is effectively .aac) coding is a more recent
and more efficient coding format than .mp3. In most
cases (though not always), the file sizes for these formats
are smaller but give the same quality of audio file. The
.wav file format is a container that often contains lossless
files, although it can also contain lossy data.
To export this audio file into .wav format, from the
File tab, select Export, then from the sub-menu select
Export as WAV, which will allow you to save the file
withdifferent sampling rates. These can be found in the
Save as type: box, like this.
We will export this into .m4a and .aac formats later in the chapter. The reasons
for using different formats are the same as for videos.
11.2.20 Sampling rate and resolution
Sampling rate
Digital audio is a series of discrete bursts called samples. Because the frequency
of these samples can be very fast it makes the sound seem continuous. A sample
rate is the number of samples of audio carried out within a given time, usually
within 1 second. It can be measured in hertz (Hz) or kilohertz (kHz). The higher
the sample rate, the more accurately the original sound can be represented and
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the better the recording sounds. The most common sample rate is 44 100Hz
(44.1kHz), which is the default in Audacity and for audio CDs. The sample rate
for DVDs is 48 000Hz and for Blu-ray Discs it is 96 000Hz.
Some lower sample rates such as 22 050Hz (used for AM radio and older, poor-
quality .mp3 recordings for floppy disk and original MP3 players) and
11 025Hz are not really suitable for music, because a great deal of sound
quality, particularly high frequency sound, is lost. Similarly, 32 000Hz is
suitable for speech but not really for music, and 8 000Hz is the lowest sample
rate and is only used for VoIP.
The human ear is limited in regard to the frequencies it can actually hear and, as
you get older, the range of frequencies that you can hear decreases. The human
ear has a hearing range of around 20 000Hz (20kHz), meaning that for high-
quality audio, the sample rate should not be below 40 000Hz (40kHz) samples
per second. If sampling rates much higher than this are used, most people
cannot hear the difference. Each sample occupies a certain amount of storage
space so the lower the sampling rate, the smaller the file size is and consequently
less storage space is required. A higher sampling rate results in more storage
space being required and a greater file size.
Sampling resolution
This is the number of bits per sound sample. The higher the sampling
resolution, the more accurately the wave form of the sound will be converted
from analogue to digital. The higher the sampling resolution, the greater
the file size. The earliest video games used 8-bit resolution. This means each
sound sample takes one of 256 different values, which is not really enough to
accurately represent music audio. The standard for compact disc audio and many
sound cards is 16-bit resolution, but modern day digital audio is normally found
in 16-bit or 24-bit resolutions.
The frequency for each sample is stored
in a number of bits, called sampling
resolution or bit depth. Each additional
bit doubles the number of values that
can be stored. If data is stored in 16-bit
format, each sampled data item can have
65 536 possible values; 24-bit audio stores
a possible 16 777 216 values. These values
are all per channel and for stereo audio
two channels are needed which doubles
the sampling and memory requirements.
New 32-bit standards are also available,
but many experts argue that the difference
between 24-bit and 32-bit is beyond
the capacity of human hearing. Data is
compressed when the audio is exported.
11.2.21 Compress to different
sample rates to suit different
media
As WAV is an uncompressed format, only
the bit rate needs to be selected in the
Save as type:box.
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11.2 Audio editing
11
If a file size is going to be too large to stream/upload/download/store, then
16-bit would be the most suitable, although some audio quality is lost. It is
a balance between quality and file size and the needs of the audience (which
have not been specified in the question). To complete thesaving for Task 11p,
select the option for 24-bit then click
.
To complete Task 11p we must export this audio file into .m4a format. From
the
File tab, select Export then from the sub-menu select Export Audio….
From the Export Audio window select, in the Save as type: box, the option
for M4A (AAC) Files (FFmpeg). You may need to download an additional dll
file in order to do this.
To export this audio file into .mp3 format for use in a
Blu-ray Disc player, we need a sample rate of 96 000 Hz
(or 96 kHz). From the
File tab select Export, then
from the sub-menu select Export as MP3. Enter the
filename Task_11p_Blu-ray. From the Export Audio
window select, in the Bit Rate Mode:, the radio
button for
Constant and usingthedrop-down menu
forQuality select 96 kbps like this.
Click
.
Activity 11i
Open the track 11i.wav in your audio editing package.
Clip this track so that it finishes after 33 seconds. Make
a second copy of this clipped track. Then on this clipped
track:
» amplify it by 10 decibels
» set a 3-second fade-in after 0 seconds
» set a 3-second fade-in after 24 seconds
» set a 3-second fade-out after 6 seconds
» set a 3-second fade-out at the end
» remove the sound between 9 and 24 seconds.
Add the track Voiceover_4.mp3 so that it starts at 10 seconds and is clearly
audible. Apply noise reduction to this track. Save your project. Mix and render
the tracks into a single stereo clip and export this clip into .wav and .mp4a
formats. Export this clip as Activity11i_DVD.mp3 for use in a DVD player.
11.2.22 Audio compression
As we have already seen earlier in the chapter, sample rate and sampling resolution
are two key elements in determining file size. Some audio compression, called
dynamic compression, works by reducing a signal’s dynamic range, this is the range
between the loudest and quietest parts of an audio signal. Compression works by
attenuating (quietening) the loudest parts of the signal and then boosting the results
so that all the quieter parts become slightly louder and the loudest parts slightly
quieter. The waveform of a compressed signal appears to be more compressed than
the original, although this gives, argue some audio engineers, better sound quality.
As stated earlier in this chapter, the two main types of compression are lossy and
lossless, although there are many types of these compressions which go beyond
the scope of this book, like multiband compression (sometimes called limiting),
lookahead compression, brickwall limiting, sidechain compression (sometimes called
ducking), mid-slide compression and parallel compression. Some of these compression
methods are used in live mixing of music during concerts, as well as audio files.
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11 SOUND AND VIDEO EDITING
11
Lossless compression does not reduce the quality of the audio file at all. Data
is not lost, so an audio file can be recreated exactly as it was when originally
created. There are a number of algorithms used to perform this and most look
for repeating patterns of data.
Lossy compression removes some of the audio file’s data and so reduces
the quality of the audio file, but does create smaller file sizes than lossless
compression. Once this data has been removed from the files it can never be
replaced. Some of the sounds in the low and high frequencies within a track are
outside the range of human hearing. For this reason, some lossy compression
software will remove these frequencies.
Most audio files are stored and streamed in containers. Even lossless formats,
like .wav files, are containers that store the audio data, sample rate, sampling
resolution (bit rate) and track numbers. Many lossy containers contain the audio
files and meta tags, which indicate which codec or codecs can be used to decode
the audio as well as the name of the artist, track, track number and so on.
Examination-style questions
You have been supplied with the following source files:
» EQ11-Bali1.mp4
» EQ11-Bali2.mp4
» EQ11-Bali3.mp4
» EQ11-Bamboo.mp3
» EQ11-Voice.mp3
You will develop a short video clip to advertise tourism in Bali. The original video
clip was filmed in Bali in August 2018 by GBRvideo and the audio was recorded
by Karla Marie.
All video and audio clips produced must be of a professional standard.
1 Open the file EQ11-Bamboo.mp3 in a suitable audio editing package. Use
noise reduction facilities to remove all background noise. Amplify the sound
from 8 seconds to the end of the clip to be the maximum volume without
clipping. Remove the first 2 seconds of the clip. Insert a silent portion into
the clip starting at 17.7 seconds and finishing at 25.4 seconds. Fade out
the clip between 16.7 and 17.7 seconds. Fade in the clip between 25.4 and
26.4 seconds. Fade out the clip between 35.3 seconds and 37.3 seconds
and remove the end of this clip at this point. Save your audio clip as
Bali_sound.mp3 in stereo with a sample rate of 44 kHz.
[14]
2
Open the file EQ11-Bali1.mp4 in your video editing software. Set the
aspect ratio to 16:9. Remove all sound from the clip. Save your video clip
as Bali1.mp4 with a resolution of 1920 x1080 pixels. [4]
3
Take a still image from the first frame of this clip. Save it with the
filename Bali1 in a format suitable for importing into your video
editing software. [2]
4
Take a still image from the last frame of this clip. Save it with the
filename Bali2 in a format suitable for importing into your video
editing software. [1]
5
Open the file EQ11-Bali3.mp4 in your video editing software. Set the
aspect ratio to 16:9. Remove all sound from the clip. Edit the speed of
the clip so that it is 0.25 x the original speed. Save your video clip as
Bali3.mp4 with a resolution of 1920 x1080 pixels.
[4]
345
11.2 Audio editing
11
6 Use the files saved in steps 1 to 5 to create a video clip to match this
storyboard.
All text should be displayed in a consistent sans-serif font.
Do not use transitions unless instructed to do so.
[27]
» Time 0 seconds:
– Background image Bali1 placed for 6 seconds.
– The text ‘Bali’ placed as a title in the top-right corner for 6 seconds.
–Audio clip Bali_sound.mp3 saved in step 1 plays.
» Time 6 seconds:
–Video clip Bali1.mp3 plays.
» Time 11.74 seconds:
– Background image Bali2 placed for 7 seconds.
– Caption text: ‘for forested volcanic mountains, iconic rice paddies,
beaches and coral reefs’ broken down into phrases.
– Added for 6 seconds.
» Time 17.74 seconds:
–Video clip EQ11-Bali2.mp3 plays.
» Time 25.38 seconds:
–Video clip Bali3.mp3 plays.
– Display appropriate credits for 12 seconds to scroll up the black area
on the left of the screen. Include the text ‘Edited by:’ followed by your
name in the credits.
7 Export your video clip as Bali_video.mp4 for use in a Blu-ray Disc player. [1]