theora dev - Sep 2005 - Theora freezes when with multiple video screens

Hello.

I have a problem with theora when using 2 video screens. The second is
connected to the dvi output of the video card. When I watch the video,
I move the renderer to the other screen and video still remains black,
or freezes, for a while.

Considerer this test : construct a graph DirectShow using GraphEdit like this :
- Webcam filter
- Theora Encoder
- Theora Decoder
- Video Renderer

Run the graph on the first screen, that looks greats. Move the
renderer to the other screen, video is black. When video is displayed
few times later, moving renderer to the first screen make the video
freeze once again.

Now, make another graph :
- Webcam filter
- Theora Encoder
- Ogg Muxer
Save the video in an ogg file.

Play the video with this graph :
- Ogg Demuxer
- Theora Decoder
- Video Renderer
Move the renderer to the other screen while graph is running, video
doesn't freeze.

Does anyone know where is the problem ?


Sebastien

I'm not sure what the problem is... but i'm pretty sure when you move
the
video from one screen to the other, windows is probebly trying to send the 
filter a signal (which it's not handling correctly) to say, "Hey
i'm using a
different buffer now!!"

One thing to try is using the VMR9 filter (Video Mixing Renderer 9) as your 
video renderer, and see if that works better.

As to the screen going black... that's somewhat common, my bought TV Tuner 
software also exhibits this problem. It in fact will only play on the screen 
it starts on.

Why it possibly occurs in a live situation and not a playback one, is that 
possibly the buffers are filling up. Try watching the memory consumption in 
task manager when this happens and see if it perhaps goes up wildly !

I'd have to take a closer look to figure it out.

Zen.
----- Original Message ----- 
From: "Sebastien Daloz" <sebastien.daloz@gmail.com>
To: <theora-dev@xiph.org>
Sent: Wednesday, September 21, 2005 5:40 PM
Subject: [Theora-dev] Theora freezes when with multiple video screens


Hello.

I have a problem with theora when using 2 video screens. The second is
connected to the dvi output of the video card. When I watch the video,
I move the renderer to the other screen and video still remains black,
or freezes, for a while.

Considerer this test : construct a graph DirectShow using GraphEdit like 
this :
- Webcam filter
- Theora Encoder
- Theora Decoder
- Video Renderer

Run the graph on the first screen, that looks greats. Move the
renderer to the other screen, video is black. When video is displayed
few times later, moving renderer to the first screen make the video
freeze once again.

Now, make another graph :
- Webcam filter
- Theora Encoder
- Ogg Muxer
Save the video in an ogg file.

Play the video with this graph :
- Ogg Demuxer
- Theora Decoder
- Video Renderer
Move the renderer to the other screen while graph is running, video
doesn't freeze.

Does anyone know where is the problem ?


Sebastien
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I tried the VMR9 filter and the problem persists.

The problem is certainly due to Theora decode filter because I used a
graph without Theora Encoder (data are first compressed with the
encoder in a graph, and a second graph take them somewhere and decode
the video to display it with the Video Renderer). So the problem
appears in a graph that only use the Decoder, so the decoder may be
the problem.

When changing display screen, DirectShow make a dynamic renegociation
on the filters (ImediaSample->getMediaType() is not null).
CTransformFilter->DecideBufferSize is called and succeeded (I have
activated logs in the filter, and DecideBufferSize ends with
***SUCCESS***).
Another thing : I know that changing display screen make all filters
to be paused. Maybe this is the problem ?

The problem is not the video card, because using another encoder
(XviD) works fine.

Memory is OK and CPU is not overloaded, problem is something else.

Note that is I add sound filters in the graph, sound is playing while
video is black. So graph is not paused but running.