> If you need ac3 pass-thru then you need to bypass PA. Just make sure > you are not using the SPDIF port for PA (use g-v-c or pavucontrol and > make sure the sound card is notconfigured for any of the 'digital > iec985' modes). If you use AC3 pass-thru, what you are really sending over the SPDIF interface is a PCM stream. The AC3 content is formatted to follow the recommendations of IEC 61937: the compressed content uses 16 of the 24-bit words, there are additional headers and lots of padding with zeroes. In terms of timing, this is really PCM. You may need to set a number of control bits in the PCM interface but nothing serious. As long as you don't mix and don't modify the bitstream, you could handle pass-thru w/ PulseAudio without major modifications. Indeed things are completely different when the content is not reformatted to meet the PCM bitrate required by SPDIF (BT, MP3, etc). Cheers - Pierre
