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jturpening
09-28-2016, 09:34 AM
Hello

Is there any way to remove the resolution limitations that scan converter has? Currently it only offers 1080, 720, and scaled. Would be great if it could be set to output the full resolution of any connected display. We do widescreen powerpoint and keynote presentations (3840x1080 or 3840x1200) are the most common resolutions. Would be great to figure out a way to output these higher resolutions over a 10gb network or thunderbolt 2 network. Bandwidth shouldn't be an issue. Even better would be to capture the screen of a 5k imac. That would get us beyond the 3840 limitation we currently have with keynote presentations. I have to confess I'm a newbie to NDI so it's possible I missed something. Please let me know if I did.

ACross
09-28-2016, 10:59 AM
Is there any way to remove the resolution limitations that scan converter has? Currently it only offers 1080, 720, and scaled. Would be great if it could be set to output the full resolution of any connected display. We do widescreen powerpoint and keynote presentations (3840x1080 or 3840x1200) are the most common resolutions. Would be great to figure out a way to output these higher resolutions over a 10gb network or thunderbolt 2 network. Bandwidth shouldn't be an issue. Even better would be to capture the screen of a 5k imac. That would get us beyond the 3840 limitation we currently have with keynote presentations. I have to confess I'm a newbie to NDI so it's possible I missed something. Please let me know if I did.

I can only speak for NewTek Scan Converter and would refer you to Sienna on their version. With that said, the real problem is not the NDI or the processor speed. The real problem is that downloading 4k frames from the GPU into system memory is a huge bottleneck and in practice will be the fundamental limit of this (and its much worse on the Mac than the PC because their GPU drivers are really a long way behind). I can also say that Scan Converter on the PC does not just scale to 1080 or 720; it does limit the maximum download bandwidth off the GPU to keep the frame-rate reasonable, but it does not limit or scale to video resolutions in any way.

Andrew

jturpening
09-28-2016, 11:40 AM
I can only speak for NewTek Scan Converter and would refer you to Sienna on their version. With that said, the real problem is not the NDI or the processor speed. The real problem is that downloading 4k frames from the GPU into system memory is a huge bottleneck and in practice will be the fundamental limit of this (and its much worse on the Mac than the PC because their GPU drivers are really a long way behind). I can also say that Scan Converter on the PC does not just scale to 1080 or 720; it does limit the maximum download bandwidth off the GPU to keep the frame-rate reasonable, but it does not limit or scale to video resolutions in any way.

Andrew

Thanks for the speedy reply and for the insight on the bottleneck. So if I understand correctly we might have better luck using windows to output widescreen powerpoint as there is no limitation on the Scan converter software for windows. Is that correct?

ACross
09-28-2016, 01:30 PM
Thanks for the speedy reply and for the insight on the bottleneck. So if I understand correctly we might have better luck using windows to output widescreen powerpoint as there is no limitation on the Scan converter software for windows. Is that correct?

Well, ScanConverter will observe Windows DPI settings which are related to high DPI screens on windows.

I want to emphasize that 4k screen capture is a big deal for computers, unrelated to Scan Converter though. For you to capture 3840x2160 at 60fps from the screen, you must copy ~2Gb/s across the PCIe bus. Most GPUs do not support video download (they are optimized for upload), and they will interrupt all GPU activity while they are downloading (because the UI cannot be changed at the same time as you are capturing it). The net effect of this is that the impact on the system of 4k capture is going to be much higher than you might imagine ... totally unrelated to NDI at all.

A.

livepad
10-11-2016, 03:20 AM
I can only speak for NewTek Scan Converter and would refer you to Sienna on their version. With that said, the real problem is not the NDI or the processor speed. The real problem is that downloading 4k frames from the GPU into system memory is a huge bottleneck and in practice will be the fundamental limit of this (and its much worse on the Mac than the PC because their GPU drivers are really a long way behind). I can also say that Scan Converter on the PC does not just scale to 1080 or 720; it does limit the maximum download bandwidth off the GPU to keep the frame-rate reasonable, but it does not limit or scale to video resolutions in any way.

Andrew

Newer versions of Sienna's NDI ScanConverter have been designed to support the iMac 5K resolution, and this is the highest resolution we have tested.

As Andrew mentions, this size of image is challenging and your results may vary.