On 25.01.2012 01:32, Mickaël Maillot wrote:
2012/1/24 Alexander Motin <m...@freebsd.org <mailto:m...@freebsd.org>>
Number of channels should be set to 8 by application when it
expects bit
rate above 6Mbps. Sample rate, as I've described, just give more
fine
control. Increasing sample rate does not automatically increase
channels. They are orthogonal:
Rate 48 96 192 48 96 192
Channels 2 2 2 8 8 8
------------------------------__----------------------------
Mbps 1.5 3 6 12 24 49
ok so set 8 channels is just to allow more bandwidth.
i just looked at alsa hdmi code (because i never find oss code that can
play hd audio),
they set 192k and 8 channels for every DTS HD / TRUEHD / E-AC3 file, so
i was thinking to do the same.
HBR mode (8 channels) is not always supported by hardware and not
defined by HDMI 1.1 spec (not sure about 1.2). So I think if possible,
it would be nice to differentiate them.
What I've forgot is to allow 8ch format. :) Add the patch below.
Hope
sound(4) has no other limitations for it.
Hmm. Looks like there is some limitation. You may grep kernel for
AFMT_PASSTHROUGH and find two "XXX force ..." comments and code,
including forcing 2 channels for AC3. Luckily for not part for
frequency is commented out. Further we may try to comment or modify
part about number of channels.
spotted and commented
--- hdaa.c (revision 230511)
+++ hdaa.c (working copy)
@@ -4979,6 +4979,8 @@
}
if (HDA_PARAM_SUPP_STREAM___FORMATS_AC3(fmtcap)) {
ch->fmtlist[i++] = SND_FORMAT(AFMT_AC3, 2, 0);
+ if (channels >= 8)
+ ch->fmtlist[i++] = SND_FORMAT(AFMT_AC3, 8, 0);
}
ch->fmtlist[i] = 0;
i = 0;
But in your case I think it should be enough to just increase sample
rate to 96 or 192KHz.
so if my problem persist after settings 8 channels, i'll blame xbmc oss
part.
Can't wait to know result. :)
--
Alexander Motin
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