Not enough speed when using AVI read

[Norbert_B]

The _fast-version of the video.

Sadly, using this compression, my player.vi went down to 25fps, with 40fps the filesize is to big to post it (even zipped).... 

Norbert 

[gsni]

Hello,

@Elmar

One second of one camera means 24MB (with compression). So, that is a bit much.

But the problem is the same, when you use for example the Heineken AVI.

In the example of Norbert it must be theoretically possible to play the avi with 72fps or more.

@Norbert

There is indeed a platform dependency. On my Laptop I reached 30fps with your example and on the video workstation there are 37fps. This applies to both AVI examples (because if you don't install a time delay, the player will get the frames as fast as possible).

Playing my AVIs using your Player, I reach 26fps. So, the resolution of the frames has an influence on the framerate, contrary to the number of frames in the AVI.

I wonder that your Laptop plays the AVIs faster than my video workstation (WinXP), because its a new one with a dual core 3,2GHz and extrem fast hard disks. Only the graphic is onboard. But I think, that has only an effect on the visualization. And the visualization has no effect on the framerate.

So, is it a NI driver problem?

And why does the VI Profiler tells me, that AVI read only needs 1ms?

The VI profiler also has a wrong overall time. Is this a hint?

Kind regards,

Gero

[Norbert_B]

---

gsni wrote:
[...]

And why does the VI Profiler tells me, that AVI read only needs 1ms?

The VI profiler also has a wrong overall time. Is this a hint?

[...] 

---

Nope, 'd say that the profiler is correct. The Profiler measures the time that a VI is actively running. Since the AVI Read Frame VI contains a call to a DLL, the profiler only takes the time to call the DLL function including all parameter-passing.

I haven't tested too deeply, but on my laptop, the player.vi keeps the 24fps for the unmodified avi. With another compression (sadly to large to post), the fps goes up to 40 fps for the fast version, keeping 24fps for the unmodified.  So i asume that the original compression just "luckily" matches that performance.....

Nevertheless, i am a little curious why you are asking all those questions. LabVIEW was never meant to play avis "in real time". If you like to do this, you could do a couple of things, including the Media Player in your VI as one option.....

hope this helps,

Norbert 

[smcclana]

I also need the ability to play back AVI's to my LabView GUI at roughly 60fps.  I have a single AVI file which I need to display 24 sequential frames at time, so I have 24 IMAQ images in a grid layout.  Each IMAQ image is updated at 2.5 fps (60fps/24 IMAQ images).

When I use the Read AVI function, it slows down to around 30fps as the previous poster mentioned.  This makes my 24 IMAQ images update at a 1fps rate.  This effect is very noticeable, and therefore I need to be able to read the AVI at full rate (60 fps).

I've attempted putting two Read AVI function blocks in two separate timed loops dedicated to different processors, but it didn't improve the performance.  It seems the Read AVI function can't be parallelized.  I realize LabView wasn't designed for fast AVI playback, but I'm hoping someone has a work-around or can recommend some add-on that might help.

Thanks,

Stephen McClanahan