[FFmpeg-user] more sound madness

Ted Park kumowoon1025 at gmail.com
Mon Mar 9 08:16:18 EET 2020


> Did you try it in Premiere, and got all the channels? Or open the output in old QT pro, and look at the properties.
> The last channels are disabled. If I enable them and save the file (destructive), a new MOOV atom is added and the current one is flagged as FREE.
> Then Premiere will accept it as it ‘should’ be.
> (Warning, Premiere has  a nasty habit to ‘remember’ files. Once it has seen a specific file, it will use the properties of the first import, even when you change it and re-import.)

Premier yes, QuickTime Pro I can’t run anymore. It starts importing all tracks in Premier, and plays all tracks by default in Quicktime Player. For a simple change I opened the file in a hex editor and set/cleared the bits by hand, each track had a flag at their track header “tkhd” box, 0x000001 enables, 0x000002 sets whether it’s part of the main presentation, etc. (If you set premier to cache metadata to a separate sidecar file alongside media files it can take the guesswork out at least, just delete the xmp to force a refresh)

I think I see what you are getting though, when I disabled tracks manually they just disappeared from the list in QT, but they were still there, just impossible to see. All ten still imported fine in Premier though.

I’m wondering what’s causing the different behavior though…

>> % ffmpeg -i /Volumes/Data/test/C0092.MP4 -i /Volumes/Data/test/068.WAV -filter_complex “[0:1]pan=1c|c0=c1[o1];[1:0]pan=1c|c0=c9[o2];[1:0]pan=1c|c0=c10[o3]” -map “[o1]" -map “[o2]" -map “[o3]"
>> -c:a pcm_s24le -map 0:0 -c:v copy -shortest /Volumes/Data/test/last2muted.mov -y
> This gives me exactly the same issue.

Huh, have you tried switching the order of the input files? I think it’s possible ffmpeg doesn’t bother to check for possibly more channels being used in the filters after guessing stereo from the first input since it’s never actually told otherwise about channels or layouts...
> Guessed Channel Layout for Input Stream #0.1 : stereo

> Now, I can live with all the sound channels in one track, only reason I’m pursuing this is that I can’t remap more than about 8 channels into a single poly track.
> (See my post from a few days ago…)

Actually could using something other than pan sidestep the whole disabling output streams issue?

% ffmpeg -i /Volumes/Data/test/C0092.MP4 -i /Volumes/Data/test/068.WAV -filter_complex “[0:1]pan=1c|c0=c1[o1];[1:0]pan=1c|c0=c9[o2];[1:0]pan=1c|c0=c10[o3]” -map “[o1]" -map “[o2]" -map “[o3]"
-c:a pcm_s24le -map 0:0 -c:v copy -shortest /Volumes/Data/test/last2muted.mov -y

% ffmpeg -i /Volumes/Data/test/068.WAV -i /Volumes/Data/test/C0092.MP4 -filter_complex "[0:a]channelmap=map=0-0|1-1:channel_layout=0x60000000,[1:a]join=inputs=2:channel_layout=0x60020000,channelmap=map=0-0|1-1|2-2:channel_layout=0x60020000[out]" -map "[out]" -c:a pcm_s24le -map 0:0 -c:v copy -shortest -y output.mov

Ted Park

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