How to see a 5.1 file's channel layout? + Channel layout error with ffmpeg

[hello_hello]

Horace did you ever get to the bottom of this? I'm having exactly the same problem, with a 5.1 MOV file created in FFMPEG playing back in VLC with the centre channel coming through the left speaker only. (this is with VLC downmixing the 5.1 to stereo - I only have 2 speakers).

In Horace's case the problem was re-mapping the channels when they didn't need remapping.

I've tried setting FFMPEG's output layout to 5.1 and 5.1(side) and it makes no difference. In VLC it plays back with the centre channel being played through left only.
Here's my FFMPEG command:
ffmpeg -i input.mov -filter_complex "[0:1]pan=FL|c0=c0[ch0];[0:1]pan=FR|c0=c1[ch1];[0:2]pan=FC|c0=c0[ch2];[0:2]pan=LFE|c0=c1[ch3];[0:3]pan=SL|c0=c0[ch4];[0:3]pan=SR|c0=c1[ch5];[ch0][ch1][ch2][ch3][ch4][ch5]amerge=inputs=6[aout]" -c:v copy -c:a pcm_s16le -map 0:0 -map [aout] output.mov
# NB stream 0 is video, streams 1-3 the 3 x stereo audio streams

If this helps at all, as an experiment I created 3 wave files. The first Front left/right, the second Centre and LFE, and the third, Surround left/right. I muxed them as an MKA in that order and then used this command line to output an MKA containing a single 5.1ch PCM audio stream with the channels in the correct order.

ffmpeg -i 3.mka -filter_complex amerge=inputs=3 -c:a pcm_s16le output.mka

Cornucopia mentioned earlier in this thread that "MOV container (and by extension, MP4) has NAMED channels and so will tell you exactly how (in what order) those channels are listed, whether using industry convention order (SMPTE/AES/EBU) or not. Unless I'm mistaken, for those formats, the order does not matter, as they are retrieved by name, not number."

I'll go on the record as still not agreeing with that one.

For playback of multi-channel files, it might help to use a player that visually shows what's happening in each channel (given you're listening in stereo as I am). If you're using Windows, ffdshow displays the individual channel volumes in it's volume filter, or foobar2000's output meter adapts according to the number of channels being decoded and their layout. It can help to at least see where stuff is when it's not where it's supposed to be.