From the beta help files (dropped from beta), do not publish this info!
About audio support for MPEG video
Because MPEG encodes both the video and audio portions of a file into a single track, encoding MPEG files as FLV files may result in the audio portion being removed (or dropped). This occurs primarily when encoding video files into FLV format on the Macintosh platform. On the Macintosh, MPEG video is imported using QuickTime. QuickTime does not support extracting audio content from MPEG files (although QuickTime will correctly playback an MPEG file with audio programming).
If you are encoding MPEG video with audio on a Macintosh, it is recommended that you first convert the MPEG video clip into another format that encodes audio and video as separate tracks within the file. You can then encode the other format as an FLV file, and preserve the audio content.
Another alternative is to use a computer with the Windows operating system. Windows imports MPEG video using DirectShow, which supports extracting both the video and audio tracks of an MPEG file. This lets you convert MPEG video into to the FLV format without removing the audio portion of the video clip.
from beta list:
Eric E. Dolecki wrote:
I believe mpeg is the only format which combines the audio and video into a single track. I’ve had to strip audio from video on the Mac, and its been the devil in the past.
So basically any other format should work as long as its QT-compatible.
Ivan Cavero Belaunde wrote:
If you absolutely have to use an MPG source, the simplest approach is to
use an MPG demultiplexing utility like bbdemux to extract the audio into
a separate file, then combine it again with the MPG file in an NLE.
In general, starting with substantially lossy video formats (normally
intended for delivery) such as MPEG, DIVX/MPEG-4, Sorenson Video, WMV,
and the like is not recommended. The lossy formats introduce artifacts
which will confuse the subsequent encoding as it will attempt to
Check out google search with keywords MPG demultiplexing utility macintosh