Adobe 65009626 User Guide - Page 88

USING SOUNDBOOTH CS4 84 Saving audio and video files Audio Format The file format used for storing encoded audio data. Some audio formats support only uncompressed audio, which has the highest quality, but uses more disk space. Some formats allow only one codec. Others allow you to choose from a list of supported codecs. Sample Rate or Frequency Choose a higher rate to increase the frequency at which audio is converted into discrete digital values, or sampled. Higher sample rates increase audio quality and file size; lower sample rates decrease quality and file size. However, setting the sample rate in the Export Settings dialog box higher than the sample rate of the audio source doesn't increase quality. Setting a sample rate different from the sample rate of the source file, requires resampling, and additional processing time. You can avoid resampling by capturing audio at the same rate at which you want to export it. Channels or Output Channels Specify how many audio channels are in the exported file. If you choose fewer channels than are in the master track of a sequence or project, Adobe Media Encoder downmixes the audio. Sample Type Choose a higher bit depth to increase accuracy of audio samples. Higher bit depth can improve dynamic range and reduce distortion, especially if you add additional processing, such as filtering or resampling. Higher bit depths also increase processing time and file size; lower bit rates reduce processing time and file size. However, setting the bit depth in the Export Settings dialog box higher than the bit depth of the source audio doesn't increase quality. Audio Interleave Specify how often audio information is inserted among the video frames in the exported file. See your capture card documentation for the recommended setting. A value of one frame means that when a frame is played back, the audio for the duration of that frame is loaded into RAM so that it can play until the next frame appears. If the audio breaks up when playing, adjust the interleave value. Increasing the value lets the computer store longer audio segments, and process them less often. However, higher interleave values require more RAM. Lowering the value can make playback smoother. Most hard disks operate best with a 1/2-second to 1-second interleave value. Setting the value to 0 disables Audio Interleave and speeds rendering time. Consider disabling Audio Interleave for projects containing assets with large pixel dimensions. Bitrate [kbps] Specifies the output bit rate of the audio. Generally, higher bit rates increase both quality and file size. This option is available for AAC, mp3, and FLV. Note: Options not documented here are specific to the selected format. For detailed information, consult the specifications for the selected format. Audiences export settings In the Export Settings dialog box, selecting Windows Media (Windows only) as the format exposes the Audiences tab. The options on the Audiences tab allow you to output variations of a movie suited to different network speeds. The player software associated with the format detects and selects the most appropriate version to ensure smooth playback. Windows Media generates a single movie that contains variations for different connection speeds. Note: Some codec-specific settings are not documented here. For more detailed information regarding a particular codec, check the documentation provided by its developer. Compressed Specifies that the codec you select in the Video tab is applied. Compressed is the default setting, and is appropriate for most users. Uncompressed Specifies that no compression is applied. Because this setting results in large files, it is not appropriate for most users. Updated 15 July 2009