[mythtv-users] SPDIF surround broken in trunk

Jean-Yves Avenard jyavenard at gmail.com
Sat Jul 17 17:26:04 UTC 2010


Hi

On Saturday, July 17, 2010, Greg Woods <greg at gregandeva.net> wrote:
> On Sun, 2010-07-18 at 01:34 +1000, Jean-Yves Avenard wrote:
> \
>> Starting to help would be to actually describe what issue you're
>> having instead a very long version of "it doesn't work"
>
> I have already done this; there has been a long thread. I have posted
> screenshots.
>

That can't be. You posted screen shots before I changed the logic in
detecting if a device is digital or not.

While ALSA reports in the description of the device that its analog,
it would now still be reported as digital just because the name is
iec958


>> > If there is anything else I can do to help troubleshoot my problem or if
>> > anyone else has seen surround sound break in recent updates, please let
>> > me know. I cannot completely rule out something I may have messed up
>> > with settings or the database, but the bottom line is that surround
>> > sound was working, I did an svn up and recompiled, and now surround
>> > sound is not working. I don't know how else to get it working other than
>> > going back to a previous version where it worked. I suppose it will be
>> > interesting to see whether or not this is successful.
>>
>> Did you update to the version I mentioned earlier, that should fix the
>> AC3 and DTS flag not showing up with your card?
>
> Yes, I am currently running 25339, more recent than the 25334 you
> recommended. These are the screenshots that I posted.

See above.

You're still not seeing the changes and ac3 and DTS still don't show?

>
>>
>> You will not get surround sound unless AC3 and/or DTS box are checked
>> with SPDIF output.
>
> OK, so it sounds like my problem is that I'm not seeing those
> checkboxes, so presumably it doesn't think any of my output devices are
> digital?

That would be the problem yes.
The name contains analog. Which usually is a pretty good hint that a
device is analog and not digital :)

>
>
>>
>> what does aplay -L and aplay -l shows on your box.
>
> Bizarre. -L shows none of the devices are digital, even the IEC958 shows
> as analog despite having "digital" in the description. -l shows that
> there is a digital output. But I haven't updated anything other than
> Myth on this box in many moons; it is still running Fedora 10. What
> should I look for in alsamixer in case I have messed something up trying
> to get this to work? I checked for the obvious and the IEC958 device is
> not muted but the IEC958 loop is. These show up as "S/PDIF" and "S/PDIF
> L" in the terminal version of alsmixer. There is also a slider labeled
> "Digital" which is not muted.
>
Unfortunately, myth can only make assumptions based on what alas
reports, and it reports analog :(

I'm going to send you a patch a tad more verbose with the logs, that
will help diagnosing what's going on.



>
>> When you select ALSA:iec958 in the list, you should have 3 checkboxes
>> showing up, the first one is visible but disabled, the 2nd one is AC3
>
> Right, but as shown in the screenshots, there are no checkboxes.
>
> [root at confusion trunk]# aplay -L
> default:CARD=CMI8788
>     C-Media CMI8788, Analog
>     Default Audio Device
> front:CARD=CMI8788,DEV=0
>     C-Media CMI8788, Analog
>     Front speakers
> surround40:CARD=CMI8788,DEV=0
>     C-Media CMI8788, Analog
>     4.0 Surround output to Front and Rear speakers
> surround41:CARD=CMI8788,DEV=0
>     C-Media CMI8788, Analog
>     4.1 Surround output to Front, Rear and Subwoofer speakers
> surround50:CARD=CMI8788,DEV=0
>     C-Media CMI8788, Analog
>     5.0 Surround output to Front, Center and Rear speakers
> surround51:CARD=CMI8788,DEV=0
>     C-Media CMI8788, Analog
>     5.1 Surround output to Front, Center, Rear and Subwoofer speakers
> surround71:CARD=CMI8788,DEV=0
>     C-Media CMI8788, Analog
>     7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
> iec958:CARD=CMI8788,DEV=0
>     C-Media CMI8788, Analog
>     IEC958 (S/PDIF) Digital Audio Output
> null
>     Discard all samples (playback) or generate zero samples (capture)
> [root at confusion trunk]# aplay -l
> **** List of PLAYBACK Hardware Devices ****
> card 0: CMI8788 [C-Media CMI8788], device 0: Analog [Analog]
>   Subdevices: 1/1
>   Subdevice #0: subdevice #0
> card 0: CMI8788 [C-Media CMI8788], device 1: Digital [Digital]
>   Subdevices: 1/1
>   Subdevice #0: subdevice #0
>


With that info, Ill simulate what's going on and try to find a work around.

>
>>
>> What's the resolution of your screen?
>
> I believe the physical TV pixels are actually 1024x768, however the TV
> can and does accept HD input. The TV says that the input signal is
> 1920x1080 (either from HDMI on the computer or directly from the cable
> STB), so that is what X is generating.


Ok. I set my pc to use 1024x768 and still the capabilities box is
never that small. Which theme are you using?


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