consider also libx264 "ultrafast" preset, GL! On Tue, Feb 13, 2018 at 7:57 AM, Alex P <[email protected]> wrote:
> I think I've figured it out. When I use nv12 or yuv420p as the input and > output pixel format, I get x1 performance. If I use bgr24/rgb24 as the > input and yuv444p as the output, I get around x0.3. > > But even when I use bgr0 for the input and output, I get less than x1. > Does anyone know what exactly bgr0 is? I can't find any information about > it in my googling. > > In your testing James, what was the pixel format? > > -----Original Message----- > From: ffmpeg-user [mailto:[email protected]] On Behalf Of > James Girotti > Sent: Monday, February 12, 2018 7:03 PM > To: FFmpeg user questions > Subject: Re: [FFmpeg-user] 4K 60Hz Directshow Video Capture > > > > > ffmpeg -f dshow -video_size 3840x2160 -framerate 60000/1001 -rtbufsize > > 2100000000 -pixel_format bgr24 -i video="MZ0380 PCI, Analog 01 Capture" > > -c:v h264_nvenc -preset lossless -f null - Gives me the same error > > > > That's surprising, I can get about 200fps using file-based/ramdisk "-c:v > h264_nvenc -preset -lossless". Have you also tried "-c:v hevc_nvenc -preset > lossless"? What's the encoding FPS that you're getting? You technically > shouldn't be able get much more than 60fps as that's what your capture card > is supplying. Can you monitor the "Video Engine Utilization" during > encoding? In linux it's listed in the nvidia-settings GUI or "nvidia-smi > dmon" on the CLI will show enc/dec%. > > > > ffmpeg -f dshow -video_size 3840x2160 -framerate 60000/1001 -rtbufsize > > 2100000000 -pixel_format bgr24 -i video="MZ0380 PCI, Analog 01 Capture" > > -c:v rawvideo -f null - > > Gets me nearly x1 performance when executing from a ram disk but > > > > ffmpeg -f dshow -video_size 3840x2160 -framerate 60000/1001 -rtbufsize > > 2100000000 -pixel_format bgr24 -i video="MZ0380 PCI, Analog 01 Capture" > > -c:v rawvideo raw.nut > > Only gets me x0.5 and the buffer overflows. > > > > Is there a way of accelerating rawvideo decoding? Would using my > > colleagues 1080 make a difference? Thanks. > > > I think raw-video is already decoded. So no way/need to accelerate that. > You might try a different pix_fmt from your capture card while using > hw-encoding, but you'd have to test. I don't know the internals, i.e. when > the pixel format is converted during hw-encoding. So it might make a > difference. > > Changing pixel formats might be a concern if you are trying to achieve > "100% lossless" capture. I've read that yuv444p should be sufficient > colorspace for bgr24. > > There isn't a lot of info out there on encoding speed differences based on > GPU models. It's a complex subject, but from what I have observed the ASIC > is tied to the GPU clock (I have observed that GPU clock speed increases as > ASIC load increases). If that's true, then a GTX 1080, with it's higher max > clock, could have faster encoding, but I have no data to back that up only. > _______________________________________________ > ffmpeg-user mailing list > [email protected] > http://ffmpeg.org/mailman/listinfo/ffmpeg-user > > To unsubscribe, visit link above, or email [email protected] > with subject "unsubscribe". > > _______________________________________________ > ffmpeg-user mailing list > [email protected] > http://ffmpeg.org/mailman/listinfo/ffmpeg-user > > To unsubscribe, visit link above, or email > [email protected] with subject "unsubscribe". > _______________________________________________ ffmpeg-user mailing list [email protected] http://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
