08.03.2015 23:00, Benjamin Tegge wrote: > Hello, > > I want to feed a 5.1 stream (dca or a52) from another device through a > iec958/spdif connection to my computer and play the audio through > loopback on the computer, I don't want to do pass-through. The C-Media > CM106-based device used with PulseAudio and the loopback module on > Ubuntu 14.04 (PulseAudio 4.0) work in stereo, but 5.1 does not. > > I wanted to set this up for quite some time, but was puzzled how all the > parts come together: > - There is iecset from the alsa tools to configure iec958 ports > (audio/data, consumer/pro), but this is just for outgoing connections, > right? > - Are there decoding functions in PulseAudio or would I have to use an > external program like ffmpeg/avconv to demux and decode the spdif > bitstream to PCM? I already found > https://www.ffmpeg.org/ffmpeg-devices.html#pulse and tried that, but > couldn't get 5.1 to work. > PulseAudio contains no decoders, so you would need to use an external tool. Also, PulseAudio does not support receiving compressed formats over spdif. Possibly this pipeline could work as a proof of concept: arecord -f dat -D spdif:1 | ffmpeg -f spdif -i - -f pulse default or: ffmpeg -f alsa -acodec ac3 -i spdif:1 -f pulse default (not tested, because I don't have anything with spdif-input capability) -- Alexander E. Patrakov
