On Thu, 2015-12-31 at 11:32 +0530, Arun Raghavan wrote: > On 31 December 2015 at 11:15, Tanu Kaskinen <tanuk at iki.fi> wrote: > > On Thu, 2015-12-31 at 09:42 +0530, arun at accosted.net wrote: > > > From: Arun Raghavan <git at arunraghavan.net> > > > > > > This will likely be needed in the future when we start supporting high > > > bitrate passthrough, and there actually seem to be people 352/384 kHz > > > out there (potentially as an intermediate production step). > > > > What's your source for claiming that there seems to be people with such > > PCM files (I'm assuming you implied PCM files)? If it's only used as an > > intermediate production step, is there any evidence that people would > > want to play that intermediate stuff via pulseaudio? > > > > The mpv bug was about a dsf file (which means a dsd stream from sacd?). > > My source is the Internet. :) > > https://en.wikipedia.org/wiki/Digital_eXtreme_Definition Thanks! It seems that DXD is used at least in one store for downloadable music[1], and it's delivered as FLAC files (so DXD is not a file format, it's just a specific set of PCM parameters). FLAC supports sample rates up to 655 kHz... [1]Â https://www.promates.com/music-store/hd-audio > > Supposedly the stream contents were non-PCM data containing more than 2 > > channels, meant to be played in passthrough mode. And I guess alsa has > > specified that such content should be wrapped in a 2-channel 384 kHz > > float fake-PCM stream? I don't like extending the rate range for PCM > > streams just because alsa's passthrough implementation happens to > > specify such parameters for fake-PCM streams, but maybe there aren't > > any better options... > > I certainly don't know of better options. FWIW, some HDA codecs do > report support for this rate as well. Presumably either the DAC > supports it (I'd be curious to find out why), or it's supported for > HBR passthrough. Either way, we'll probably need to end up supporting > this. Yes, there seem to be good reasons to bump the max rate. -- Tanu
