[mythtv-users] MythTV 0.24 HDMI audio problem

[Steven Adeff]

On Fri, Nov 19, 2010 at 2:47 AM, Jean-Yves Avenard <jyavenard at gmail.com> wrote:
> On 19 November 2010 15:01, Steven Adeff <adeffs.mythtv at gmail.com> wrote:
>> ssh in, use mplayer with "-ao alsa:device=hw=1.3", I can replace 3
>> with 7, 8 or 9 and all will playback stereo from mp3, AC3 and DTS from
>> movies, and my 96KHz 24bit FLAC from HDTracks.
>>
>> here's what it shows in the frontend log,
>> 2010-11-18 22:32:38.650 AO: Opening audio device 'hw:1,7' ch 2(6) sr
>> 48000 sf signed 16 bit reenc 0
>
> What about if you used hw=1,7

hw= with anything does not work at all.

> Okay..
>
> I see a bug there...
>
> I the mean time, uncheck DTS and AC3 and you will get sound until the
> fix is pushed through.

yes, that is what I'm doing. Not ideal, but in theory there should be
no difference since it is passing multichannel LPCM over HDMI.

>> So, it looks to be with how Myth is trying to open the device and pass
>> AC3/DTS through. I also don't quite understand why in mplayer I can
>> use 3,7,8, or 9 but Myth seems to only work with 7?
>
> If you check the XBMC page I linked to earlier, you will find that
> those devices aren't all equal.
>
> Some can do stereo only and won't work with AC3 or DTS passthrough.
>
> Did you use passthrough in mplayer ?

I understand, but in mplayer it works for all four devices no matter
what, which could just be a smart parsing on mplayer's part, or?  yes,
I run mplayer with "-ac hwac3,hwdts,". Actually, I have it in my
~/.mplayer/config

what's more annoying is that I can't get AC3/DTS passthrough for any
of the devices.

>> So I tried using 1,3 for mp3 music, and it plays, but the quality
>> sounds as though its been downmixed to some horrible quality level.
>> 24/96 produces static. same with 8 and 9.
>>
>> anymore info I can provide?
>
> As above, not all those hdmi devices are equal and some will only work
> for stereo, 16 bits audio.
>
> Please understand that the issue is with alsa, you shouldn't have that
> many devices to start with. This will probably get fixed in a future
> version of the drivers.

fair, but again, it works in mplayer for all cases, so things should/can work.

>> Duncan, I seem to have the same problem. I was able to get it to work
>> using "ALSA:plughw:1,7" except the new audio code doesn't seem to like
>> that if you do a device scan. I haven't had time to play with it, but
>> the last time I tried I was able to get it to work with the ALSA:HDMI.
>>
>> I too, like Tom have a GT220 as the second audio device. I think this
>> may be why the ALSA:HDMI setting doesn't work?
>>
>> I also can't get Myth to play 96KHz FLAC I've downloaded from
>> HDTracks, all I get is static, which I was under the impression should
>> be working in 0.24.
>
> okay.
>
> Can you try the following
> in audio device, enter ALSA:plughw:1,7
>
> in Advanced Audio Configuration -> Separate digital output device,
> also enter ALSA:plughw:1,7 (do not select default)..
>
> Does it work any better?
>
> try with different device: plughw:1,x with x=1 to whatever aplay -L showed
>
> I believe this should fix your immediate problem, until I can find out
> how to set the iec bit with devices entered as plughw:card#,device#

I believe I did try ALSA:plughw: but did not get anywhere as no sound
came out no matter what device I chose. I'm out of town for the
weekend but will try either tonight before I leave, or Sunday when I
get back home.

Thanks JYA for looking into this, as well as all the work you've done
with the audio code. For me, being able to play 96/24 FLAC is worth
all of this "pain", if your ever in Boston, I owe you a few rounds at
the pub!

-- 
Steve
http://www.mythtv.org/wiki/User:Steveadeff
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