Hi - I'm working with a post-production workflow to mux 5.1 wav audio into a mov file (each channel specified as a separate track), with correct channel assignments written as metadata. I'm able to get everything except for the Center channel to appear correctly when viewed in Quicktime, however the Center channel shows up as 'mono'.
I'm using a command like this (other channels omitted for the sake of brevity): ffmpeg -i input.mov \ -i audio.wav \ -filter_complex "[1:0]pan=FC|c0=c0[FC]" \ -map 0:v \ -map "[FC]" \ -c:v copy \ -c:a pcm_s24le \ output.mov This ends up writing a 'chan' tag that indicates Mono content (MOV_CH_LAYOUT_MONO). If I use a different channel, such as "FL", it writes a value that Quicktime understands (layout=MOV_CH_LAYOUT_USE_BITMAP bitmap=0). After some tracing, it appears that this configuration comes from the layout defined in mov_ch_layout_map_1ch for a single center channel. This seems like intended functionality and not a bug, but unfortunately doesn't solve my issue. I previously noticed that ffmpeg doesn't currently support writing channel labels -- I've just submitted a patch to add this fallback when a layout isn't found (for a semi-related situation, DownmixLeft/DownmixRight => LeftTotal/RightTotal tracks). One potential solution I've found for this is adding a flag which exclusively writes using channel labels instead of layouts. I can cleanup and submit this patch if desired, which adds a -movflags use_channel_labels (Link #1 below). I don't know enough to be sure that this is the right approach; however, it does work and shows up correctly in Quicktime Pro. I'm looking for some advice here on the best path forward -- I'm more than happy to implement whatever is needed. Thanks, -Courtland [#1]: https://github.com/Frugality/FFmpeg/commit/5ed6413fc9b17fd1bdd25672e959e934799f7b53 _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
