Sony vegas pro 12 has unstable rendering with CUDA and OpenCL.

[John Rofrano]

[Nigel O'Neill] “Abusive tones and rude language is the fastest way to get alienated and ignored.”

Thanks Nigel, I was holding my tongue. 😉 (biting it is more like it lol)

~jr

http://www.johnrofrano.com
http://www.vasst.com

[Nigel O’neill]

Thanks. What really peeves me is users of this forum who think this is an official support forum of Sony’s. It is not. It is community supported, but perhaps they don’t realise it.

I have to admit the advice I get here is tons better than the official Sony support forum.

[Anders Salvesen]

Ok.

But why doesnt my i7-3770k with 4 cores and 8 threads render faster than my old i5-760?

And whats the point of gpu support aka OpenCL and cuda if it only give better quality of the preview video?

[John Rofrano]

[Nigel O'Neill] “I have to admit the advice I get here is tons better than the official Sony support forum.”

Thanks Nigel. I know the people here who are providing answers on their own free time appreciate that.

You know it’s a conundrum…

Here at the COW we are in an international community that spans the range of video professionals who are fighting to meet their next deadline, to hobbyists who just want to preserve their video memories or record their game play, and to each one the answer to their specific question is important. The problem, of course, is that the skill set of these individuals varies widely as does the ages. We don’t know if someone started editing just this week or have been doing so for years, or if they are 12 years old or 40 years old (which by the way, is no indication of their level of proficiency).

To be a good teacher, you must answer the student’s question with a response that is appropriate for their level of understanding. This is easy in a classroom setting with prerequisites for the course but unfortunately here at the COW we don’t know what their understanding is so we have to take cues from the way that the question is asked and make some assumptions. There aren’t a whole lot of topics in video production where the answer is black & white, yet it may not be appropriate to explain all of the shades of grey to someone who just wants to know what parameter to use. So sometimes I take the liberty of simplifying my answers to give an answer that I feel is appropriate for the situation. Someone who doesn’t realize this and is only reading that one answer may not fully understand that context.

Rick Qi was correct that 32-bit mode contains more color data and is therefore more accurate, and if it were just a matter of adding processing time with no harm done, then it may have been an acceptable answer; but Anders said that he was using Pixel format 32bit floating point (full range) because some YouTube video said it was better and Full Range can really mess you up if you don’t know what you’re doing because most plug-ins are expecting video levels and not full range levels. Some plug-ins simply don’t work correctly in 32-bit mode. There have been numerous posts of people not getting the video levels they expected because they used a pixel format that was inappropriate for the work they were doing. So this YouTube recommendation has side-effects and rather than go into all of the reasons why, I recommended that you keep your project 8-bit video levels unless you have a good reason to change it. If Anders was having a problem like color banding that I thought 32-bit mode could fix, I would have recommended 32-bit video levels; but he didn’t.

I try not to over explain things unless someone asks why. If all you want is a simple answer, then I strive to make my answer as simple as possible, but no simpler. 😉

~jr

http://www.johnrofrano.com
http://www.vasst.com

[John Rofrano]

[anders salvesen] “But why doesnt my i7-3770k with 4 cores and 8 threads render faster than my old i5-760?”

The problem with multi-threading is that you need multiple things to do. Not all of the renderers in Vegas Pro are multi-threaded and some take advantage of multi-threading better than others.

For example on my Intel Core i7-3930K Sandy Bridge-E 3.2GHz using MainConcept MPEG2 and AVC I get about 88% CPU utilization but with Sony AVC I only get 22%! Also see if GPU rendering is enabled because that will use more GPU than CPU power.

[anders salvesen] “And whats the point of gpu support aka OpenCL and cuda if it only give better quality of the preview video?”

Who said it only affects preview? Vegas Pro has had accelerated GPU rendering since version 10.0 and in version 12.0 it adds GPU acceleration for FX which also increases rendering speed even more.

~jr

http://www.johnrofrano.com
http://www.vasst.com

[Rick Qi]

I apologise for my second language to lead you misunderstand my meaning. The point is Vegas does poor performance on rendering the project if you compare with Adobe. I should say Vegas supplies a high efficent tool on editing the clips but it often drives me crazy when I render the project as video files. For example, the incorrect color, flick of black screen or something else….. These artifacts appear in the output files occasionally no matter how it looks perfectly in pre-view windows. That’s why I only import & export the AAF files in Vegas to do editing work and leave rendering job to the others. It seems far away from the original topic.

[Anders Salvesen]

But when i spoke to people at overclock.net, they say that gpu support only will help the preview video to be enhanced, and not the rendering performance itself.

But Windows movie maker on the other hand seems to be able to use gpu support very vell. Render twice as fast as Vegas.

[John Rofrano]

[anders salvesen] “But when i spoke to people at overclock.net, they say that gpu support only will help the preview video to be enhanced, and not the rendering performance itself.”

Tell the people at overclock.net to read this article by Sony:

Five steps to GPU power in Vegas Pro 11

Then tell them to do some tests for themselves. With the timline preview GPU turned on, have them add some GPU accelerated FX to the events on the timeline and render to a format that doesn’t use the GPU for rendering. Then have them turn off the timeline GPU and render the file again to the same format and they will see that the renders takes a lot longer (about 5x longer in my test). This is because the timeline acceleration and GPU accelerated FX are absolutely used during the render.

You can test for yourself too. I placed Bump Map and Starburst on an event and rendered it. With GPU on it took 52 seconds. With GPU off it took 315 seconds (5:15). That’s over 5x improvement in render time with the GPU (and that’s not the rendering GPU because I used CineForm as my render format which is not GPU enabled)

~jr

http://www.johnrofrano.com
http://www.vasst.com