[mythtv-users] Recent DVD problems with video and audio drops

[Neil Salstrom]

On Fri, Jan 18, 2013 at 3:14 PM, Richard <peper03 at yahoo.com> wrote:
> I can't see anything that immediately screams 'this is what the problem is',
> but I've only been looking at this code for a couple of months so maybe I'm
> not seeing something that someone else would.
>
> What artefacts are you getting on playback exactly?  Just stuttering?
> Blockiness?  Picture frozen?
>
> Could you try playing the DVD with an OpenGL playback profile and see
> whether that's any better?  I investigated the DVD last night that had a
> frozen picture around the chapter marks.  The chapters marks are actually
> fairly irrelevant but I got some of the same logs as you (not all).  I found
> it was due to the timecode on the audio stream resetting, which screwed up
> sync with the video stream.  Playback using the OpenGL profile was fine
> (it's not VDPAU itself that is at fault - more the way the frames are
> prepared).
>
> I have a demo DVD with a video intro that won't play with VDPAU but I
> haven't analyzed why yet.  The video flickers, is distorted and has various
> artefacts.  Possibly it's the same problem as you're seeing but it's hard to
> say.
>
> Playback with OpenGL would definitely be a good test.
>
>
> Richard.
>
>
>
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Richard,

Here is a playback log using openGL.

http://pastebin.com/1rSv9dzP

I was contacted by someone off list who said he's been experiencing
the same problems I've seen.  He did not mention the movie titles but
it's an issue that has cropped up recently.

The problem was seen with both VDPAU and OpenGL.  I had 'top' going in
a terminal window on my laptop as it was playing on my HTPC.  CPU
never went above ~30% using OpenGL and ~10% with VDPAU.  When it
happens I do not see any blocking in the picture or something similar
to pixilation.  What I see are brief pauses ever second or so.  The
picture is very juddery and audio drops out during the judder.  The
picture remains clear but it looks like it drops a pile of frames.
There can be times where the movie goes several minutes without
problem then it starts up for several minutes of judder.

What I am curious about is:

2013-01-18 17:27:17.976224 I  Trying to match best refresh rate 29.970Hz
2013-01-18 17:27:17.976279 I  Trying 1920x1080 59.939 Hz
2013-01-18 17:27:18.030063 I  Dynamic TwinView rate found, set
59.9394Hz as XRandR 54
2013-01-18 17:27:18.175301 I  SwitchToVideo: Video size 720 x 480:
    Switched to displaying resolution 1920 x 1080, 487mm x 274mm

Ok, so is this upconverting to 1080p?  The DVD is 29.970Hz then it's
doubling the frame rate to 59.939Hz and going from 480p to 1080p?

Once it starts playing and the judder starts we see this:

2013-01-18 17:28:24.160577 D  DVDRB: DVDNAV_NAV_PACKET
2013-01-18 17:28:24.233484 I  Player(0): FPS:   24.18 Mean: 41354
Std.Dev:  9959 CPUs: 20% 19% 18%
2013-01-18 17:28:24.802166 D  DVDRB: DVDNAV_NAV_PACKET
2013-01-18 17:28:25.451091 I  Player(0): Waiting for video buffers...
2013-01-18 17:28:25.486048 D  DVDRB: DVDNAV_NAV_PACKET
2013-01-18 17:28:25.521649 I  Player(0): Waiting for video buffers...
2013-01-18 17:28:25.577362 I  Player(0): Waiting for video buffers...
2013-01-18 17:28:25.683569 I  Player(0): Waiting for video buffers...
2013-01-18 17:28:25.822837 I  Player(0): Waiting for video buffers...

Why is it playing at 24.18 FPS when before it was reported at 29.970 FPS?

There are lots of "Waiting for video buffers".  No idea what is going on!

Thanks for your help,

Neil