<div><div><div dir="auto">I am in touch with Nvidia & while it builds, it doesn’t run correctly for some reason. Difficult to debug because they use a closed source per-built lib.</div></div><div dir="auto"><br></div><div dir="auto">That’s why I am trying to figure out how they used xcb (which it sounds like they did).</div><div dir="auto"><br></div><div dir="auto">They’re trying to figure out why. Its docs are from 2015.</div></div><div><div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, Aug 5, 2019 at 10:21 PM James Jones <<a href="mailto:jajones@nvidia.com" target="_blank">jajones@nvidia.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">If you want to do this specifically on NVIDIA cards with NVENC, you'll <br> more than likely want to be using this:<br> <br> <a href="https://developer.nvidia.com/capture-sdk" rel="noreferrer" target="_blank">https://developer.nvidia.com/capture-sdk</a><br> <br> This will be much faster and lower latency than grabbing desktop content <br> using shared memory via XCB commands.<br> <br> Thanks,<br> -James<br> <br> On 8/5/19 9:49 AM, Suhail Doshi wrote:<br> > Thanks so much Peter. I'll look at this stuff today.<br> > <br> > Question: Do you have any guidance on how to extract/use the OBS library <br> > that's cross-platform? I wouldn't want to include everything that OBS <br> > has to offer to keep the footprint of our application low. Any docs on <br> > their API as well?<br> > <br> > Suhail<br> > <br> > --<br> > <br> > Founder<br> > <br> > <br> > On Mon, Aug 5, 2019 at 9:20 AM Peter Harris <<a href="mailto:peter@harr.ca" target="_blank">peter@harr.ca</a> <br> > <mailto:<a href="mailto:peter@harr.ca" target="_blank">peter@harr.ca</a>>> wrote:<br> > <br> > On 2019-08-05 11:07 a.m., Suhail Doshi wrote:<br> > > My question is: Is there a way to get an image of the desktop that<br> > > returns a pointer that's GPU memory? For example, in Windows 10,<br> > there's<br> > > an API called the Desktop Duplication API which will allows you to do<br> > > this. Then, it lets you copy the data in that GPU memory block to<br> > > another one such that you can encode the frame with H264, for<br> > example. I<br> > > am using NVIDIA GPUs and utilizing their NVENC SDK.<br> > ><br> > > I am looking for an equivalent.<br> > <br> > XCB is very low-level. For most things, you probably want to use a<br> > higher level library (such as, for example, OBS:<br> > <a href="https://github.com/obsproject/obs-studio" rel="noreferrer" target="_blank">https://github.com/obsproject/obs-studio</a> , which includes a<br> > cross-platform library with an API that is probably closer to the<br> > Desktop Duplication API than anything in XCB).<br> > <br> > With that said, if you want to implement the details yourself, you can<br> > take a peek inside OBS and see that the capture method that copies<br> > uncompressed pixels back to main memory uses xcb_shm_get_image (and<br> > xcb_xfixes_get_cursor_image, and xcb_xinerama_query_screens, among other<br> > things).<br> > <a href="https://github.com/obsproject/obs-studio/blob/master/plugins/linux-capture/xshm-input.c" rel="noreferrer" target="_blank">https://github.com/obsproject/obs-studio/blob/master/plugins/linux-capture/xshm-input.c</a><br> > <br> > Peter Harris<br> > <br> > <br> > _______________________________________________<br> > Xcb mailing list<br> > <a href="mailto:Xcb@lists.freedesktop.org" target="_blank">Xcb@lists.freedesktop.org</a><br> > <a href="https://lists.freedesktop.org/mailman/listinfo/xcb" rel="noreferrer" target="_blank">https://lists.freedesktop.org/mailman/listinfo/xcb</a><br> > <br> </blockquote></div></div>-- <br><div dir="ltr" class="m_-7070519220509347404gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div dir="ltr"><br></div><div dir="ltr">Suhail</div><div dir="ltr"><br></div><div dir="ltr">--</div><div dir="ltr"><br></div><div dir="ltr">Founder</div></div></div></div></div> </div>