At Wed, 13 Aug 2008 13:17:44 +0200, Clemens Ladisch wrote: > > Takashi Iwai wrote: > > Charles Eidsness wrote: > > > It looks like the parse_audio_format_i_type function at line 2369 of usbaudio.c > > > (linux v2.6.23) doesn't support the case where bSubframeSize (fmt[5]) = 4 bytes > > > and bBitResolution (fmt[6]) = 24 bits, which should correspond to a S24_LE (or > > > BE) type. I'm developing a new USD DAC which supports this mode (24-bit sample > > > in a 4 byte package). Right now Linux sends me S32_LE formated data, which is > > > wrong. Would it be possible to expand this function to support S24_LE/BE? It > > > would only require adding a few lines of code. > > > > Yes, it's possible, of course. > > > > BTW, is this behavior strictly defined? I fail to find in the > > usb-audio spec that bBitResolution specifies the lower bits, not the > > higher bits... > > The spec assumes that 24-bit samples use S24_3LE. 24-bit samples in > 32-bit words are an extension that must be handled with some device- > specific code (like with the UA-1000). > > (The audio 2.0 spec allows 32-bit words, and the wording seems to imply > that samples are aligned to the most significant bit, i.e., that S32_LE > would be used in this case.) OK, thanks for clarification. Takashi _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
