Apple Compressor 2 - Manual (Page 155)

Chapter 11 Creating MPEG-4 Output Files 155
Video Pane
The Video pane allows you to make settings for the quality (ISMA profile), frames per
second (fps) rate, key frame interval, and bit rate of your MPEG-4 Part 2 output file. The
pane contains the following controls:
 Video Enabled checkbox: Make sure that this box is selected if you want the MPEG-4
Part 2 output format video settings to be applied.
 ISMA Profile buttons: Choose from one of the following MPEG-4 Part 2 quality settings:
 Basic (0): Ensures playback on all MPEG-4 Part 2 devices.
 Improved (1): Gives better output quality, but this setting is not compatible with
older MPEG-4 Part 2 devices.
 Frame Rate (fps) pop-up menu and field: Choose or enter a number to set the overall
frame rate of your output media file.
 Key frame interval field: Enter a value to designate how often (number of frames) you
want keyframes created in your output media file.
 Bit Rate pop-up menu: Choose from one of the following bit rate settings. Whatever
setting you choose, quality will vary from frame to frame to maintain the selected
bit rate.
 Constant at: Sets a manually specified bit rate based on your slider setting.
 Low VBR: Sets an overall low quality for all frames.
 Medium VBR: Sets an overall medium quality for all frames.
 High VBR: Sets an overall high quality for all frames.
 Bit rate slider and field: (Only available with the “Constant at” setting.) Move the slider
to set the overall video bit rate for your output media file between the range of
32 Kbps to 2048 Kbps, or enter a specific number in the accompanying field.
Either enter a number in the Bit
Rate field or use the slider to set
the bit rate (only available with
“Constant at” setting).