Hi list,
I'm trying to get the fastest possible frame rate from GEM, and seem to be hitting a limit of 60fps. Is this a known limit? I searched the documentation and pd-list archives, but maybe I'm missing something. The final application I'm working on is video tracking, but here's a test patch with nothing more than a gemwin and a counter incremented by the gemhead. With a frame rate of 90 for the gemwin, it takes exactly 3 seconds to get the counter up to 180, when it should only take 2 seconds. At a frame rate of 60, it takes the expected 2 seconds to get the counter to 120.
I'm running this with Pd-0.43-2 and GEM 0.93.3 on Ubuntu 12.04 using the -noaudio flag. I get the same results on Mac OS 10.6.8.
GEM is set to VBL sync based on your monitor's refresh rate. I vaguely recall putting some sort of message about turning this on and off in the gemwin. With it off you will often see horrible tearing artifacts on the display, which is why it defaults to 'on' on OSX (and apparently Linux too).
On Wed, May 30, 2012 at 3:15 PM, William Brent william.brent@gmail.comwrote:
Hi list,
I'm trying to get the fastest possible frame rate from GEM, and seem to be hitting a limit of 60fps. Is this a known limit? I searched the documentation and pd-list archives, but maybe I'm missing something. The final application I'm working on is video tracking, but here's a test patch with nothing more than a gemwin and a counter incremented by the gemhead. With a frame rate of 90 for the gemwin, it takes exactly 3 seconds to get the counter up to 180, when it should only take 2 seconds. At a frame rate of 60, it takes the expected 2 seconds to get the counter to 120.
I'm running this with Pd-0.43-2 and GEM 0.93.3 on Ubuntu 12.04 using the -noaudio flag. I get the same results on Mac OS 10.6.8.
-- William Brent www.williambrent.com
“Great minds flock together” Conflations: conversational idiom for the 21st century
www.conflations.com
Pd-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
hello, on Linux, you can change vertical syncro that using nvidia-settings tools if you use a nvidia GPU. Otherwise, i don't know, certainly tweking the Xorg.conf. (look for"sync to Vblank")
Using triple buffer may provide solution for faster than screen rendering, but i don't see the point in that. If you have a shader or somthing else that sould be faster than sreen rendering, you still can bang gemhead with a metro...
cheers cyrille
Le 30/05/2012 21:22, chris clepper a écrit :
GEM is set to VBL sync based on your monitor's refresh rate. I vaguely recall putting some sort of message about turning this on and off in the gemwin. With it off you will often see horrible tearing artifacts on the display, which is why it defaults to 'on' on OSX (and apparently Linux too).
On Wed, May 30, 2012 at 3:15 PM, William Brent <william.brent@gmail.com mailto:william.brent@gmail.com> wrote:
Hi list, I'm trying to get the fastest possible frame rate from GEM, and seem to be hitting a limit of 60fps. Is this a known limit? I searched the documentation and pd-list archives, but maybe I'm missing something. The final application I'm working on is video tracking, but here's a test patch with nothing more than a gemwin and a counter incremented by the gemhead. With a frame rate of 90 for the gemwin, it takes exactly 3 seconds to get the counter up to 180, when it should only take 2 seconds. At a frame rate of 60, it takes the expected 2 seconds to get the counter to 120. I'm running this with Pd-0.43-2 and GEM 0.93.3 on Ubuntu 12.04 using the -noaudio flag. I get the same results on Mac OS 10.6.8. -- William Brent www.williambrent.com <http://www.williambrent.com> “Great minds flock together” Conflations: conversational idiom for the 21st century www.conflations.com <http://www.conflations.com> _______________________________________________ Pd-list@iem.at <mailto:Pd-list@iem.at> mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
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Thanks Chris & Cyrille. I don't have an nvidia GPU, so I'll see what I can find in the Xorg.conf. For totally digital displays, how does the refresh rate come into play? I'm seeing out there that VBL doesn't apply to digital.
I tried single buffer mode with each metro tick banging the gemhead and then clearing the gemwin, but got jittery results with the video stream. I haven't looked at triple buffering, is there some documentation you could point me to on that? The reason I want faster than screen rendering is that I'm doing video tracking. If the control streams from the tracking algorithm can be updated faster than the refresh rate, that would be ideal. Or is it not possible to run an algorithm on frames that fall between the cracks of the refresh rate and aren't fully displayed on the screen?
On Thursday, May 31, 2012, Cyrille Henry wrote:
hello, on Linux, you can change vertical syncro that using nvidia-settings tools if you use a nvidia GPU. Otherwise, i don't know, certainly tweking the Xorg.conf. (look for"sync to Vblank")
Using triple buffer may provide solution for faster than screen rendering, but i don't see the point in that. If you have a shader or somthing else that sould be faster than sreen rendering, you still can bang gemhead with a metro...
cheers cyrille
Le 30/05/2012 21:22, chris clepper a écrit :
GEM is set to VBL sync based on your monitor's refresh rate. I vaguely recall putting some sort of message about turning this on and off in the gemwin. With it off you will often see horrible tearing artifacts on the display, which is why it defaults to 'on' on OSX (and apparently Linux too).
On Wed, May 30, 2012 at 3:15 PM, William Brent <william.brent@gmail.commailto: william.brent@gmail.com> wrote:
Hi list,
I'm trying to get the fastest possible frame rate from GEM, and seem to be hitting a limit of 60fps. Is this a known limit? I searched the documentation and pd-list archives, but maybe I'm missing something. The final application I'm working on is video tracking, but here's a test patch with nothing more than a gemwin and a counter incremented by the gemhead. With a frame rate of 90 for the gemwin, it takes exactly 3 seconds to get the counter up to 180, when it should only take 2 seconds. At a frame rate of 60, it takes the expected 2 seconds to get the counter to 120.
I'm running this with Pd-0.43-2 and GEM 0.93.3 on Ubuntu 12.04 using the -noaudio flag. I get the same results on Mac OS 10.6.8.
-- William Brent www.williambrent.com http://www.williambrent.com
“Great minds flock together” Conflations: conversational idiom for the 21st century
www.conflations.com http://www.conflations.com
______________________________**_________________ Pd-list@iem.at mailto:Pd-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/** listinfo/pd-list http://lists.puredata.info/listinfo/pd-list
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Le 31/05/2012 14:36, William Brent a écrit :
Thanks Chris & Cyrille. I don't have an nvidia GPU, so I'll see what I can find in the Xorg.conf. For totally digital displays, how does the refresh rate come into play? I'm seeing out there that VBL doesn't apply to digital.
If you don't sync to VBlank, the screen can display the top of an image, then a new image is rendered so the bottom of a screen display the new image.
I tried single buffer mode with each metro tick banging the gemhead and then clearing the gemwin, but got jittery results with the video stream.
certainly the same kind of what you'll get without VBlank sync.
I haven't looked at triple buffering, is there some documentation you could point me to on that?
i did not find lot's of documentation around this. it's just a flag for nvidia card, i don't know if other allow it too. internet is your friend.
The reason I want faster than screen rendering is that I'm doing video tracking. If the control streams from the tracking algorithm can be updated faster than the refresh rate, that would be ideal. Or is it not possible to run an algorithm on frames that fall between the cracks of the refresh rate and aren't fully displayed on the screen?
best is to stay with 60Fps, sync to VBlank, for the rendering part. (you can't go faster than the screen anyway). for video tracking, if you got a fast camera, you can use a gemhead at other speed than the rendered one : stop the gemhead sending it a 0, then use a metro to bang the gemhead at the desired frequency.
cheers c
On Thursday, May 31, 2012, Cyrille Henry wrote:
hello, on Linux, you can change vertical syncro that using nvidia-settings tools if you use a nvidia GPU. Otherwise, i don't know, certainly tweking the Xorg.conf. (look for"sync to Vblank") Using triple buffer may provide solution for faster than screen rendering, but i don't see the point in that. If you have a shader or somthing else that sould be faster than sreen rendering, you still can bang gemhead with a metro... cheers cyrille Le 30/05/2012 21:22, chris clepper a écrit : GEM is set to VBL sync based on your monitor's refresh rate. I vaguely recall putting some sort of message about turning this on and off in the gemwin. With it off you will often see horrible tearing artifacts on the display, which is why it defaults to 'on' on OSX (and apparently Linux too). On Wed, May 30, 2012 at 3:15 PM, William Brent <william.brent@gmail.com <mailto:william.brent@gmail.com>> wrote: Hi list, I'm trying to get the fastest possible frame rate from GEM, and seem to be hitting a limit of 60fps. Is this a known limit? I searched the documentation and pd-list archives, but maybe I'm missing something. The final application I'm working on is video tracking, but here's a test patch with nothing more than a gemwin and a counter incremented by the gemhead. With a frame rate of 90 for the gemwin, it takes exactly 3 seconds to get the counter up to 180, when it should only take 2 seconds. At a frame rate of 60, it takes the expected 2 seconds to get the counter to 120. I'm running this with Pd-0.43-2 and GEM 0.93.3 on Ubuntu 12.04 using the -noaudio flag. I get the same results on Mac OS 10.6.8. -- William Brent www.williambrent.com <http://www.williambrent.com> <http://www.williambrent.com> “Great minds flock together” Conflations: conversational idiom for the 21st century www.conflations.com <http://www.conflations.com> <http://www.conflations.com> _________________________________________________ Pd-list@iem.at <mailto:Pd-list@iem.at> mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/__listinfo/pd-list <http://lists.puredata.info/listinfo/pd-list> _________________________________________________ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/__listinfo/pd-list <http://lists.puredata.info/listinfo/pd-list>
-- William Brent www.williambrent.com http://www.williambrent.com
“Great minds flock together” Conflations: conversational idiom for the 21st century
www.conflations.com http://www.conflations.com
Pd-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
On Thu, May 31, 2012 at 8:36 AM, William Brent william.brent@gmail.comwrote:
Thanks Chris & Cyrille. I don't have an nvidia GPU, so I'll see what I can find in the Xorg.conf. For totally digital displays, how does the refresh rate come into play? I'm seeing out there that VBL doesn't apply to digital.
The refresh rate for LCD is 60Hz although internally many process at 120 or even higher.
I tried single buffer mode with each metro tick banging the gemhead and then clearing the gemwin, but got jittery results with the video stream.
Without syncing to the refresh rate the video display will be jittery and also have tearing artifacts. As Cyrille points out there are ways to run gemheads at higher speeds, but you want to keep all of the drawing objects at refresh rate.
Ok, thanks again Chris and Cyrille. That helps a lot, and I'll see what I can do from this point.
William
On Thu, May 31, 2012 at 12:06 PM, chris clepper cgclepper@gmail.com wrote:
On Thu, May 31, 2012 at 8:36 AM, William Brent william.brent@gmail.com wrote:
Thanks Chris & Cyrille. I don't have an nvidia GPU, so I'll see what I can find in the Xorg.conf. For totally digital displays, how does the refresh rate come into play? I'm seeing out there that VBL doesn't apply to digital.
The refresh rate for LCD is 60Hz although internally many process at 120 or even higher.
I tried single buffer mode with each metro tick banging the gemhead and then clearing the gemwin, but got jittery results with the video stream.
Without syncing to the refresh rate the video display will be jittery and also have tearing artifacts. As Cyrille points out there are ways to run gemheads at higher speeds, but you want to keep all of the drawing objects at refresh rate.