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

Pierre autourduglobe p.autourduglobe at gmail.com
Wed May 15 23:22:30 CEST 2019

Yes, I am also inclined to believe that my video card is the culprit... 
for the lack of frame rate. It would not be able, through Open-GL, to 
decode simultaneously the 5 streams (composer + 4 mixers).

I've never played any games on my computers either... but "gamer" cards 
are much cheaper than pro cards, while being relatively powerful, and 
that's why I've always chosen them for video editing.

My current video card dates from 2014, it's a Nvidia GTX-750ti:

It includes 2 GB of GDDR5 memory, 128-bit memory interface and a 
Bandwidth of 86.4 GB/s

If it becomes clear that it is the guilty one... I'm ready to buy 
another more powerful one.

I started looking at what could be bought, which would not be too 
expensive and would be compatible with my current power supply (which I 
don't want to change).

I also don't know if Nvidia video cards or AMD cards would be the most 
compatible and optimized for Cinelerra-GG.

Here are the models I'm considering right now:

- Nvidia GeForce GTX 1070 (8GB, 256-Bit GDDR5, Bandwidth 256 GB/s
- Nvidia GeForce GTX 1660 Ti (6GB, 192-Bit GDDR6, Bandwidth 288 GB/s
- AMD Radeon RX 580 (8GB, 256-Bit GDDR5, Bandwidth 256 GB/s
- AMD Radeon RX 570 (4GB, 256-Bit GDDR5, Bandwidth 224 GB/s

But I'm not ready to buy right now....


On 19-05-15 16 h 21, Phyllis Smith wrote:
> 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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