[Cin] Observations using GPU on DNxHD and MPEG proxy while running CinelerraGG

[Phyllis Smith]

Pierre:

>From your last 2 emails and tests as compared to what I see, I am thinking
that the graphics board is the bottleneck.  Doing similar tests with the
Clowns, as compared with your observations below, I am always getting close
to 29.97 fps in either X11 or X11-OpenGL.  The reason I think it is
probably your graphics board is because my laptop is not really a "work"
computer but rather a "gaming" computer (it was an inexpensive AMD computer
that has never, ever played a single game!) so I would imagine the graphics
board is meant to be pretty good.

The results of these tests of the mpeg proxies tell me that with both
> the X11-OpenGL driver and the X11 driver, using vdpau results in a very
> slight reduction in the use of my CPU, but that this does not improve
> the frame rate possible that these video drivers allow to display...
>

The above seems to indicate that the graphics board does not improve
anything and you have plenty of CPU anyway, so you might as well use that.

>
> X11 allows in all cases to display at least 29.97 frame/sec sources that
> have been shot at this speed.
>
> X11-OpenGL is always limited to a maximum of about 12 frames/sec.
>
> These results are approximately true for all the types of media I
> tested, whether DNxHD.mov, HDV (MPEG-2.m2t), AVC H264.mp4 or even
> proxies in mpeg.mpeg.
>
> Given these results, I don't really see the advantage of using
> proxies... In any case, the video driver used will determine the
> possible frame rate regardless of the type of media used.
>
> I'm actually wondering if the constant frame rate limit of 12 frames/sec
> provided by X11-OpenGL in my tests with 4 mixers, regardless of the
> media type, doesn't actually indicate a bug somewhere or a limit
> inherent in my equipment. But then how do you explain the best
> throughput with X-11?
>

Instead of working with 29.97 fps media, I loaded Big Buck Bunny which is
60 frames per second.  And there may be something strange going on as
Pierre indicated that I will have to test on a faster computer.  Because
when I played this, like Pierre, it seems to limit it at always 30 fps
whether I user X11 or OpenGL.  Then when I proxy it to 1/2, I thought I
should have improved the frame rate but it too was at only 30 fps.

I will have to do the tests on GG's computer to eliminate the possibility
of a limitation / bug.  Phyllis
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