[mythtv-users] Problems with vdpau decoding HD content

Scott Russell list-mythtv at bluecamel.eml.cc
Thu May 13 14:31:45 UTC 2010

On May 13, 2010, at 9:59 AM, Tom Lichti wrote:

> On Thu, May 13, 2010 at 9:26 AM, Scott Russell
> <list-mythtv at bluecamel.eml.cc> wrote:
>> On May 13, 2010, at 1:14 AM, Scott wrote:
>>> This is a general query to help me with my troubleshooting of a playback problem on my FE.
>>> I have an ASRock 330 ION loaded with Mythbuntu 10.04 and the 0.23-fixes SVN 24572. The system uses the VDPAU Normal profile and is configured for 512MB of GPU RAM in BIOS.
>>> Playback with both recorded 720p and 1080i (OTA ATSC from a HDHR) shows seems to run into a glitch. The show starts off fine and pausing, FF/RW, and commercial skip all work fine. At some point, usually 12-30 minutes, the video starts jumping and sometimes the audio too. I see "prebuffering pause" messages logged in mythfrontend.log.
>>> To resolve the problem I have to reboot the system. To be sure, the following does NOT resolve the problem:
>>> 1) pause/unpause the show
>>> 2) stop/start playback again
>>> 3) exit mythfrontned and start mythfrontend again
>>> 4) exit X11 and start it again
>>> Thoughts? Is anyone else having trouble with vdpau and HD recordings on 0.23?
>> Following up on my own status, I've tried the following additional steps. These have not resolved the problem:
>> 1) Enabled OpenGL sync in MythTV settings
>> 2) Verified 512MB of video memory was set in BIOS
>> 3) Added UseEvents On to the xorg.conf
>> 4) Reset FE back to default prefs (removed from FE prefs from converg.settings table on the BE)
>>        - Set theme to blue-abstract
>>        - Set audio out to ALSA:hdmi
>>        - Enabled DTS and AC3 pass through
>>        - Enabled VDPAU Normal profile
>> A log of the problem before I did these latest changes is available at:
>> http://pastebin.com/GZDB18CU
>> I started playback of a 720p source at time code 2010-05-11 22:13:08.711 and the video problem starts at time code 2010-05-11 22:18:17.811.
>> -- Scott
> Have you checked your network? I had a similar problem, and the cause
> was having three switches between the frontend and the backend. With
> them both on the same switch, I don't see the problem anymore. I am on
> Gig-E as well, which I think helps a lot as well.
> Tom

I haven't looked at the network yet. Since this is a FE/BE combo, I think everything plays over the network using the myth:// protocol. if this was NFS I would know how to optimize for it, but I'm not exactly sure what myth:// is. Anyway, I'll do a trace and see if there is an excessive amount of retransmits, dup acks, or other problems indicating problem at the network level.

FWIW, I'm also on a GigE network. My experience tells me that 100mb is plenty to stream HDTV 1080i over. Or so that's what the Silicon Dust people say when they justify a 100mb port on the back of the HDHR.

-- Scott 

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