Hi Benjamin, *Sun Mar 8 11:22:30 PDT 2015* *Alexander E. Patrakov* <patrakov at gmail.com> <pulseaudio-discuss%40lists.freedesktop.org?Subject=Re%3A%20%5Bpulseaudio-discuss%5D%20How%20to%20decode%20and%20loop-back%20and%0A%09iec958/spdif%20bitstream%3F&In-Reply-To=%3C54FC9366.4080908%40gmail.com%3E> : > 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 <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 > > Were you able to make it work? I'm trying to do the same thing now, but it looks like CM106 does not allow me to record a compressed format and I get a complete silence instead. I even wrote a small app to do the decoding ( https://github.com/Shulyaka/pareceive) which does not work because of this fact. Best regards, Denis Shulyaka -------------- next part -------------- An HTML attachment was scrubbed... URL: <https://lists.freedesktop.org/archives/pulseaudio-discuss/attachments/20170817/ff7ad7be/attachment.html>
