Jacob Meuser <jake...@sdf.org> wrote: > > Strangely, AC3/DTS pass-through does *not* work. > > there's this comment in cmpci.c: > > /* disable ac3 and 24 and 32 bit s/pdif modes */ > > and then the relevant register bits are cleared. feel free to play > with making it work ;)
I would, but there shouldn't be anything required to make it work. The point of AC3/DTS pass-through mode is that it sends what looks like 16-bit stereo audio at the S/PDIF level. It's only the receiver that, on seeing a signature bit pattern, re-interprets the data and decodes it according to AC3 or DTS. We don't use any "AC3 mode" for azalia(4) either and pass-through works there. The failure with cmpci(4) is quite mystifying. If you munge the bits of an AC3/DTS pass-through stream, for example by running it through aucat -v100, the signature will be destroyed and the receiver will simply treat the data as PCM audio. This doesn't happen here. My receiver seems to see a signature but never synchonize. -- Christian "naddy" Weisgerber na...@mips.inka.de
