Re: em28xx: msi Digivox ATSC board id [0db0:8810]

[Matthew Gyurgyik <matthew@pyther.net>]

On 12/06/2012 10:21 PM, Devin Heitmueller wrote:
> On Thu, Dec 6, 2012 at 8:40 PM, Matthew Gyurgyik <matthew@pyther.net> wrote:
>> I was able to do a bit of testing tonight and this is what I found.
>>
>> A channel scan was unsuccessful:
>> http://pyther.net/a/digivox_atsc/dec06/scan.txt (no errors in dmesg)
>>
>> Changing channels by pressing "h" in "mplayer dvb://" caused mplayer to
>> crash and this messages to be logged in dmesg
>> http://pyther.net/a/digivox_atsc/dec06/dmesg_mplayer_switch_channels.txt
> This looks like a combination of a misconfiguration of GPIOs and
> mplayer not properly handling an exception condition.  You should
> definitely bring this up with the mplayer developers since their app
> shouldn't crash under this circumstance.

Sorry I misspoke. mplayer isn't crashing, however it can't read data 
from the tuner and thus closes.

for completeness, mplayer output: 
http://pyther.net/a/digivox_atsc/dec06/mplayer_channel_switch.txt

>
>> Audio is out-of-sync in mplayer. Using cache helps, but over time the audio
>> still goes out of sync.
>> http://pyther.net/a/digivox_atsc/dec06/mplayer_audio_out_of_sync.txt
> This has nothing to do with the tuner.  The tuner delivers the MPEG2
> stream already compressed and synchronized.  If you're playback is
> out-of-sync, it's probably your ALSA drivers, PulseAudio, or mplayer
> that is the culprit.
Ok that make sense, I'd bank it being on mplayer and how it reads the 
stream.

>
>> Using azap to tune and using cat /dev/dvb/adapter0/dvr0 > test.mpg to
>> generate a test.mpg
>>
>> mplayer plays the file fine without audio-sync issues, but VLC and Xine
>> refuse to play it. (is this normal?)
> What errors are VLC or Xine showing?  Unless the stream is really
> corrupt VLC and Xine should play it fine.  And if the stream were
> corrupt it wouldn't play with mplayer either?  This sounds like bugs
> in VLC and Xine.
I would agree with. I got the chance to test another mpeg from my other 
tuner (that I know works well) and had the same issue.

The vlc errors consist of similar messages such as those below:
> [0x7f0200c015a8] ts demux warning: lost synchro
> [0x7f0200c015a8] ts demux debug: skipping 187 bytes of garbage
I had thought I was able to play previous captures in VLC. I was unable 
to test my other card (that I know works well) last night. Now I see 
this is not the case, and it separate issue.

> There's definitely something going on in the tuner which is causing
> the channel scan to fail (and probably the tuning failure in mplayer).
>   But all the stuff with actual playback causing segfaults, A/V sync
> issues, and failures to play back in certain applications are all
> userland problems that you would need to raise with the developers for
> those respective projects.
>
> Cheers,
>
> Devin
>
> --
> Devin J. Heitmueller - Kernel Labs
> http://www.kernellabs.com