The output of $ ffmpeg -layouts is useful to understand the terminology that FFmpeg uses for the most common layouts. The syntax requires some understanding of stream specifiers, but with a bit of reading (and FFprobe/mediainfo), you'll get there. join includes channel layout and map functions, that avoid the need for running separate layout and channelmap filters. If you play the mp4 file with VLC you clearly hear that something is swapped badly.If you want to convert multi-stream mono to a single multi-channel stream and set the channel layout then use either join or amerge+channelmap. The following are 30 code examples of ffmpeg.output().You can vote up the ones you like or vote down the ones you dont like, and go to the original project or source file by following the links above each example.
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 These instead are the waveforms of the transcoded file:Īgain let me post the ffprobe parts related to the audio: 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.
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