[FFmpeg-user] ProRes422 with 8 audio tracks converted to mp4 -- muffles audio 4

Harvey Pikelberger communque at gmail.com
Thu Nov 22 19:28:20 EET 2018

> On Nov 22, 2018, at 8:50 AM, Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:
> 2018-11-22 17:44 GMT+01:00, Harvey Pikelberger <communque at gmail.com>:
>> ffmpeg -i ffmpeg -i SoundMappingTest-I-8Discreet.mov -map 0 -g 48 -c:v
>> libx264 -profile:v baseline -crf 16 -c:a aac -b:a 256k -vf scale=1280:720
>> -pix_fmt yuv420p SoundMappingTest-I-8Discreet.mp4
> You (apparently) cannot copy the timecode track from mov to mp4
> but this is what you request with "-map 0".
> Default behaviour would be to transcode one video and one audio
> track.

Does the timecode issue explain the 'Conversion Failed'?
It seemed that the error that stopped the conversion was what appeared in the subsequent notes, having to do with not recognizing the codec:
- Could not find tag for codec none in stream #2, codec not currently supported in container
- Could not write header for output file #0 (incorrect codec parameters ?): Invalid argument
- Error initializing output stream 0:1 -- 

Also, my understanding of -map 0 was that it maps not one video / one audio but maintains the track map, matching all tracks from source to destination file.
That's, in fact, the behavior I'm seeing when I run the same command using a DNx source file with the same 8 tracks of audio.

Also note: The above CLI didn't fail to convert from ProRes / QT in FFmpeg v4.0.1
The conversion went through, only with LFE sound on track 4.   Now in FFmpeg v4.1 we're getting the error -- but only for the ProRes source, not the DNx source.  That works fine.

More information about the ffmpeg-user mailing list