[Cin] pcm bluray encoding

Thanks to Paul (who wrote a lot of ffmpeg code) I hacked this patch against ffmpeg-4.4. Can anyone test how it work with 5.1 and stereo sounds (s16, s24 broken ATM), especially if it remaps 5.1 channels correctly? I tested like this: $ ./ffmpeg -i ~/matrixbench_highdivx_ac3.avi -c:v libx264 -s 160x120 -c:a pcm_bluray -mpegts_m2ts_mode 1 -sample_fmt s16 1.m2ts mpv 1.m2ts but my tablet sound definitely not 5.1! NOTE: this is not yet cinelerra-gg patch, just something I test with our version of ffmpeg