When importing avi files, ffmpeg_handler identifies number of channels as 1 even if the video have stereo audio. You can see this in the log if you start mediatomb with the --debug option.
2011-03-08 22:43:37 DEBUG: [../src/metadata/ffmpeg_handler.cc:163] addFfmpegResourceFields(): Added duration: 01:51:09.0 2011-03-08 22:43:37 DEBUG: [../src/metadata/ffmpeg_handler.cc:171] addFfmpegResourceFields(): Added overall bitrate: 1760 kb/s 2011-03-08 22:43:37 DEBUG: [../src/metadata/ffmpeg_handler.cc:193] addFfmpegResourceFields(): FourCC: 44495658 = XVID 2011-03-08 22:43:37 DEBUG: [../src/metadata/ffmpeg_handler.cc:205] addFfmpegResourceFields(): Added resolution: 720x306 pixel 2011-03-08 22:43:37 DEBUG: [../src/metadata/ffmpeg_handler.cc:222] addFfmpegResourceFields(): Added sample frequency: 44100 Hz 2011-03-08 22:43:37 DEBUG: [../src/metadata/ffmpeg_handler.cc:232] addFfmpegResourceFields(): Added number of audio channels: 1
In the specific video above, mp3 stereo audio, samplerate 44100Hz, bitrate 256 kbps was used.
Problem seen in mediatomb 0.12.1 (Didn't find a group for this version) running on Ubuntu 10.10.