Sound Effects Editor for AVI Movies

This program allows you to add background sound and sound effect to your AVI movies. You can co-ordinate specific sounds by playing them at a specific frame and have either the option to mix in the sound with a background track or replace the background sound. All audio WAV formats are acceptable but for any one AVI you must use a consistent audio format, e.g. 22KHz 8 bits Mono WAV files.

The Application

When the program is executed the following window will be displayed:

utils_sound1.gif (18509 bytes)

 

The application window consists of four important components:

The basic operation of the program is as follows:

Important Note:
Any sound effects added to an AVI file will not be evident until the animation has been saved to a file. So if you want to preview the results of your work. Save the animation and reload it.

The detailed operation of the program follows on from the description of the actions of the buttons in the toolbar and from the commands on the program's System Menu:

 

The Toolbar

The actions of each button in the toolbar is as follows:

utils_sound2.gif (2151 bytes)

Button A:
Clicking on this button brings up a dialog of AVI files, choose the one you want to work with. The dialog includes a preview capability. If a movie is loaded that does not contain any sound track a dialog will pop up from which you must select the format of the sound track. Sound tracks have three basic properties:

  1. Sampling frequency: Choose either 11kHz, 22kHz, or 44kHz (44 kHz is CD audio quality sampling rate).
  2. Bits per sample: Choose either 8 bits or 16 bits
  3. Mono or stereo: Choose either Mono or Stereo.

utils_sound3.GIF (3386 bytes)

All sounds on a single track must have the same values of each of these parameters. Thus if you sound samples are taken from a collection of audio CDs you will probably need to choose (44kHz, 16 bits Stereo)

Button B:
Clicking this button bring up a sound file dialog. (WAV and AVI type files, some AVI files will probably not contain any sound but some might). Choose the files you want to add to the sound list. The sounds can be previewed if required.

Button C:
Save the edited movie to a file. (Once saved the move can be re-loaded and the sound effects previewed.)

Button D:
Insert the selected sound (Highlighted item in sound list) at the current frame. The sound will play for however long it lasts. The sound completely replaces the existing soundtrack. The original soundtrack will appear again at the end of the insertion.

Button E:
Mix in  the selected sound (Highlighted item in sound list) at the current frame. The sound will play on top of the original soundtrack for however long it lasts. The sound mixes at equal volume with the existing soundtrack. The original soundtrack will appear again in its original form at the end of the mix.

Button F:
Silence the soundtrack. This lays down a new soundtrack. At this stage you can select an alternative format for the soundtrack, such as sampling frequency etc.

Button G:
Clear the sound list. Remove all the currently loaded sounds so that you can start building a new sound list.

Button H:
Displays a dialog about the sound properties. It display information about the sound track on the movie and the currently selected sound in the sound list. (Use this information to decide which sounds can be added to which movies - Remember the movie audio track must have the same properties as any sound dubbed onto it.)

utils_sound4.GIF (3506 bytes)

In the example illustrated above the currently selected sound could not be added to the movie being edited unless a new sound track is written to the move file (Button F)

Button I:
Play the currently selected sound. (To remind yourself of what it was!)

Button J:
Show the first frame of the movie (Position the current work frame at the start of the movie).

Button K:
Step back one frame.

Button L:
Play the movie.

Button M:
Step forward one frame.

Button N:
Show the last frame of the movie (Position the current work frame at the end of the movie).

Button O:
Make a copy of the video to another AVI file.

Button P:
Dub the sound from the current movie onto another selected from a file open dialog.

Button Q:
Provide information about this utility, its version number etc.

 

The Status Display

The "Status Display" line provides some instructions and is the place to look for information about the current movie file and selected sound clip. The image below illustrates this:

utils_sound5.GIF (14019 bytes)

Above the status line the display: [Frame 41 of 60 (2.7s)] give information about the current frame of the movie, its frame number and time into playing. The status line is at the bottom of the application window and it gives information about both the movie [Video] and currently selected audio clip [Sound]:

For the movie:

In the example: [640x480x24 60 Frames 4.0s]  A resolution of  640 by 480 pixels (VGA resolution) 24 bit (true colour) display, 60 frames duration and playing time of 4 seconds.

For the currently selected sound:

In the example: [2Ch 22.05kHz 1.7s 16] A stereo sample recorded at a rate of 22kHz (remember the famous sampling theorem tells us that this allows us to reproduce sound perfectly up to a maximum bandwidth of half the sampling frequency i.e. 11kHz, - the human ear can hear up to about 18kHz, the telephone bandwidth is 3kHz). The sound clip lasts for 1.7 seconds and each sample is recorded to a resolution of16 bits.

 

The System Menu

A few additional commands, that dub on a complete audio track from another move, write the current movie sound track to an audio WAV file for example are executed by selecting them from the program's system menu.