You can automatically create IMA compressed soundtracks with your movies. IMA is a 4:1 "lossy" audio compression technique that works with 16 bit sound. You can get an IMA compressed 22 kHz, 16 bit audio track into the same space as uncompressed 11 kHz, 8 bit audio track. Even though the 22 kHz, 16 bit sound is compressed, it usually sounds dramatically better than the uncompressed 11 kHz, 8 bit sound. The following chart shows the size of compressed and uncompressed files for comparison.
Sound (mono) With IMA Without IMA
44 kHz, 16 bit 22 kps 88 kps
22 kHz, 16 bit 11 kps 44 kps
11 kHz, 16 bit 5.5 kps 22 kps
To create a movie with an IMA compressed audio track, select "IMA" in the compression pop-up inside the Audio Section of the Advanced settings.
NOTE: You need Sound Manager 3.2 or later to create movies with IMA audio - it is included on the Movie Cleaner Pro 1.2 disk for your convenience. Simply replace the older version of the Sound Manager in your Extensions folder (in the System folder) with version 3.2. System 7.5.3 or later has the new Sound Manager built in - if you have System 7.5.3 or later installed, you don't need to change your Sound Manager.
Audio Resampling
Movie Cleaner Pro 1.2 automatically uses a high quality audio resampling method which produces significantly better results than version 1.1.1. You don't need to set anything to take advantage of high quality resampling - it is always used (when was the last time you wanted a movie with bad audio?)
For those of you who are curious, the resampler uses a sine-algorithm method.
"No Audio" option
This feature is convenient when you want to compress a movie and not include its soundtrack. Simply turn on the "No Audio" check-box in the Audio section of the Advanced settings window, and the resulting movie will have no sound track.
NOTE: When the "No Audio" check box is selected, the data-rate specified in the Compress section is the video data-rate only, and no longer includes room for the audio track. When this option is not checked, the data-rate specified is a total rate and includes the audio as well as the video.
For example, if the "No Audio" option was selected, and you indicated that you wanted a 180 kps movie, you would get a movie with a video track of 180 kps and no audio track. If the option was not selected, and you specified 180 kps (and your audio was 11 kHz, 8 bit), you would get a video track of 169 kps and an audio track of 11 kps for a total data-rate of 180 kps.
