Problem
I want to convert the MOV file containing the separated FL/FR audio streams to MP4 file, transcoding the video to h264 and the audio to AAC. However, it fails with the following error:
[aac @ 0x7ff515000c00] Unsupported channel layout "1 channels (FL)"
The source video and command what I used is as the following section.
How To Reproduce
Download ticket1474.mov
as the source from https://trac.ffmpeg.org/ticket/1474,
this source contains the following streams:
(The streams in issue are #0:1 and #0:2)
Stream #0:0(eng): Video: mpeg2video (Main) (xdvf / 0x66766478), yuv420p(tv, bt709, progressive), 1920x1080 [SAR 1:1 DAR 16:9], 34801 kb/s, 29.97 fps, 29.97 tbr, 2997 tbn, 59.94 tbc (default)
Metadata:
creation_time : 2012-06-19T21:18:43.000000Z
handler_name : Apple Video Media Handler
encoder : XDCAM EX 1080p30 (35 Mb/s VBR)
timecode : 00:00:00;00
Stream #0:1(eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz, 1 channels (FL), s16, 768 kb/s (default)
Metadata:
creation_time : 2012-06-19T21:18:43.000000Z
handler_name : Apple Sound Media Handler
Stream #0:2(eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz, 1 channels (FR), s16, 768 kb/s (default)
Metadata:
creation_time : 2012-06-19T21:18:43.000000Z
handler_name : Apple Sound Media Handler
Stream #0:3(eng): Data: none (tmcd / 0x64636D74)
Metadata:
creation_time : 2012-06-19T21:18:43.000000Z
handler_name : Time Code Media Handler
reel_name : Untitled
timecode : 00:00:00;00
Then run the following command:
$ ffmpeg -i ticket1474.mov -b:a 128k -map 0 -y sample.mp4
You'll get the following error:
(snip)
Stream mapping:
Stream #0:0 -> #0:0 (mpeg2video (native) -> h264 (libx264))
Stream #0:1 -> #0:1 (pcm_s16le (native) -> aac (native))
Stream #0:2 -> #0:2 (pcm_s16le (native) -> aac (native))
Stream #0:3 -> #0:3 (copy)
(snip)
[aac @ 0x7ffbd203e400] Unsupported channel layout "1 channels (FL)"
Error initializing output stream 0:1 -- Error while opening encoder for output stream #0:1 - maybe incorrect parameters such as bit_rate, rate, width or height
Conversion failed!
ffmpeg Version
$ ffmpeg -v
ffmpeg version N-93875-gc2771bbf81-tessus
Note: Stable version (ffmpeg-4.2) also fails.
What I Tried (Converting FL/FR streams to dual mono channel)
I guessed the problem can be solved if I could convert FL/FR streams to dual mono streams.
But I couldn't find the appropriate usage of ffmpeg for such scene.
The command I have tried is the following which also failed:
$ ffmpeg -i ticket1474.mov -b:a 128k -filter_complex '[0:1]pan=mono|FC=FL[mono];[0:2]pan=mono|FC=FR[mono]' -y sample.mp4
(snip)
Filter pan has an unconnected output
Any ideas?