ffmpeg AAC "Can not resample 6 channels..."
When you try to encode with ffmpeg and you end up with such an error
Resampling with input channels greater than 2 unsupported. Can not resample 6 channels @ 48000 Hz to 6 channels @ 48000
you are probably trying to encode from AAC with 5.1 audio to less than 6 channels or different audio sampling rate.
There are three solutions:
- As a solution either do not reduce the audio channels and change the audio sampling rate or do convert the audio with faad first.
- Apply one of the available ffmpeg patches to fix the AAC 6 channel issue...
- Split video and audio and convert audio separately.
The third solution can be done as following:
- Extract audio with ffmpeg:
ffmpeg -y -i source.avi -acodec copy source.6.aac
- Convert audio with faad:
faad -d -o source.2.pcm source.6.aac
- Merge video and audio again with ffmpeg:
ffmpeg -y -i source.avi -i source.2.pcm -map 0:0 -map 1:0 -vcodec copy -acodec copy output.avi
Update: As hinted by a fellow commentter the big disadvantage is the quality loss as faad can only convert into PCM 16bit.