[alsa-devel] [PATCH] cmipci - allow capture of raw spdif subframes
tiwai at suse.de
Tue Nov 13 11:15:34 CET 2007
At Tue, 13 Nov 2007 16:47:38 +0300,
Timofei V. Bondarenko wrote:
> Takashi Iwai wrote:
> > At Wed, 07 Nov 2007 15:12:46 +0300,
> > Timofei V. Bondarenko wrote:
> >> Hi.
> >> Enable capturing of raw 32bit IEC958_SUBFRAME.
> >> The 24-bits PCM data can be obtained using iec958 plugin.
> >> Known problem: captured stream may begin with either left or right
> >> subframe. Since the iec958 plugin doesn't decode preamble it may swap
> >> the channels sometime.
> >> Regards,
> >> Tim.
> > Applied this one, too.
> > (Do you happen to have a fix for iec958 plugin, too? :)
> Not yet.
> I'm in doubt about a clean way to drop one subframe from the raw stream.
> Could you give me a hint?
It'll be tricky, yes. We can prepend a zero in the first shot and
keep one pending channel data to shift. For example,
raw: R0 L0 R1 L1 R2 L2 ... R(n-1) L(n-1) | R(n) L(n) ...
dec: 0 R0 L0 R1 L1 R2 ... L(n-2) R(n-1) | L(n-1) R(n) ...
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