I am using SVN 677 and a recent SVN built of FFMPEG on an Ubuntu 10,10 and Ubuntu 10.04 system (problem shows up on both)

Transcoding of video does not work unless I specify the audio codec "copy"
Specifying any other audio codec just leads to the situation that the transcoding simply does not proceed right after it started, and ultimately the UPNP client gives up.
Enabling log level 3 does not seem to reveal any particular issue but I am happy to share any log or config file if it helps.

I have used the FLV example from the Wiki :
<file ext="flv">
  <type>VIDEO_ITEM</type>
  <mime_type>application/x-flash-video</mime_type>
  <transcode enabled="true">
    <ext>mpg</ext>
    <mime_type>video/mpeg</mime_type>
    <transcoder>ffmpeg</transcoder>    
    <video_codec>mpeg1video</video_codec>
    <audio_codec>mp2</audio_codec>
    <audio_samplerate>44100</audio_samplerate>            
    <video_bitrate>1800000</video_bitrate>
  </transcode>
</file>

This fails on both my Ubuntu 10.10  and Ubuntu 10.04 system. I have used two clients (iPad and XMBC client)
I have tested other transcoding setups, and they all failed unless I specified "copy" as the audio codec.
Since I am trying to get to a MP4 compatible transcode, this does not suffice.

I am leaning toward blaming FFMPEG, but on the other hand encoding the files on the command line seems to work just fine.

Any hint would be highly welcome