Specifications
35
A Digital Video Primer
You can import AVI les and sweeten audio tracks while you watch video playback, then resave
the AVI le with a new audio track. e editing tools in Adobe Audition enable you to be as
precise in your cuts as you like, with editing control down to the sample level and automatic
zero-crossing detection to avoid pops when you make cuts. You can also add crossfades
and automation envelopes to smooth transitions and balance the over-all volume; and you can
change tempo without shiing pitch or shi pitch without changing tempo.
When you need to produce audio quickly, you can build a soundtrack from thousands of high-
quality royalty-free loops that are included with Adobe Audition. e loops come in a wide
variety of musical styles, and exceptional looping controls in Adobe Audition make them easy to
work with. In addition, the loops automatically conform to the global session tempo and key.
e tools in Adobe Audition give you the power to create rich, nuanced audio at 32-bit resolu-
tion using any sample rate up to 10 MHz. Precise sample rate conversion guarantees high-quality
results, and is ideal for upsampling CD material from 44.1 kHz to 48 kHz for video or 96 kHz for
audio DVD. Adobe Audition also includes sophisticated audio restoration features. When you’re
ready for the nal mix, you can use the powerful mastering and analysis tools, which all run
natively at 32-bit resolution. Batch processing tools save you time by automating repetitive tasks,
such as le format conversion, and matching the volume of multiple les. With the multichannel
encoder, you can easily transform any mix into a surround sound experience.
Adobe Audition provides extensive support for industry-standard audio le formats, including WAV, AIFF, MP3,
mp3PRO, WMA, and WMAPro.
Synchronization issues
To make sure the audio tracks synchronize properly with the video, you need to consider audio
sample rates in relation to the timebase and frame rate of your project. It is a common mistake
to create a movie at 30 fps with audio at 44.1 kHz, and then play back the movie at 29.97 fps (for
NTSC video). With the video playing at 29.97 fps and the audio at 30 fps, at some point you will
notice that the audio starts to get ahead of the video. e dierence in frame rates results in a
synchronization discrepancy that appears at a rate of one frame per 1000 frames, or one frame
per 33.3 seconds (just under two frames per minute). If you notice audio and video driing apart
at about this rate, check for a project frame rate that doesn’t match the timebase.