user14689: I want to demux the audio from avi files, so that the files are lossless. I tried both Yamb and Ffmpeg. Both produce files less than 1 MB (for a video of 80 MB), which are unplayable through VLC. I tried avidemux, and it says it can't export in copy mode.

user1871: Your audio is PCM, but you're trying to streamcopy to AAC, which won't work.
To extract the audio to WAV, use
ffmpeg -i DSCN5008.AVI -acodec copy -y a.wav

To transcode the audio to AAC, use
ffmpeg -i DSCN5008.AVI -acodec aac -y a.aac

Note that AAC isn't lossless. But FLAC is a lossless and compressed codec.
ffmpeg -i DSCN5008.AVI -acodec flac -y a.flac


14689: <p>I want to demux the audio from avi files, so that the files are lossless. I tried both Yamb and Ffmpeg. Both produce files less than 1 MB (for a video of 80 MB), which are unplayable through VLC. I tried avidemux, and it says it can't export in copy mode.</p>
 1871: <p>Your audio is PCM, but you're trying to streamcopy to AAC, which won't work.</p>

<p>To extract the audio to WAV, use</p>

<pre><code>ffmpeg -i DSCN5008.AVI -acodec copy -y a.wav
</code></pre>

<p>To <strong>transcode</strong> the audio to AAC, use</p>

<pre><code>ffmpeg -i DSCN5008.AVI -acodec aac -y a.aac
</code></pre>

<p>Note that AAC isn't lossless. But FLAC is a lossless and compressed codec.</p>

<pre><code>ffmpeg -i DSCN5008.AVI -acodec flac -y a.flac
</code></pre>
