If you play the mp4 file with VLC you clearly hear that something is swapped badly. Transcoded file: Stream #0:1(eng): Audio: aac (LC) (mp4a / 0圆134706D), 48000 Hz, 5.1, fltp, 488 kb/s (default)Ĭhannel positions : Front: L C R, Back: L R, LFEĬhannel positions : Front: L C R, Side: L R, LFE configuration: -enable-gpl -enable-version3 -disable-w32threads -enable-avisynth -enable-bzlib.

These instead are the waveforms of the transcoded file:Īgain let me post the ffprobe parts related to the audio: Not a member of Pastebin yet Sign Up, it unlocks many cool features D:fmpeg-64>binfmpeg -probesize 500000000 -i sample-uncompressed-lr-audio.mov -vcodec libx264 -mapchannel 0.1.0 -mapchannel 0.1.1 output.mp4.

These are the waveform of the input file:

to better explain what happens I made a screenshot of before and after waveforms in Adobe Audition. What happens is that even if video processing is ok, for the audio part my channels are mapped incorrectly. The version I'm using is ffmpeg version N-87584-g47d6b02f6c-Reino a pretty new one. In order to do so I tried to use this command: ffmpeg -y -i input.mov -c:v libx264 -preset ultrafast -b:v 10000k -c:a libfdk_aac -afterburner 1 -cutoff 20000 -filter:v 'scale=-1:720' output.mp4 I need to transcode some high res videos (prores or dnxhd files with 5.1 uncompressed 48kHz audio in MOV container) to their low res h264 with AAC keeping the audio still in 5.1 preserving their channel mapping.

Ffmpeg map audio channels