Thank you for that suggestion Roger, I can't believe I forgot about the preset options.
Executing the following on a RAM disk gets me about .9x performance, letting me capture about 5 seconds worth of video before the buffers overflow and I lose frames. Not perfect but enough for what I need. I think this is the best I'm going to get unless the mfg makes a better driver and adds yuv444p support or I get a better CPU. I really appreciate for everyone's input. ffmpeg -f dshow -video_size 3840x2160 -framerate 60000/1001 -rtbufsize 210000000 -pixel_format bgr24 -i video="MZ0380 PCI, Analog 01 Capture" -c:v libx264rgb -preset ultrafast -crf 0 -pix_fmt bgr24 -t 00:00:10 -r 60000/1001 out.avi One more question, what is the command to use the maximum buffer size? -rtbufsize INT_MAX doesn't work. Thanks. -----Original Message----- From: ffmpeg-user [mailto:ffmpeg-user-boun...@ffmpeg.org] On Behalf Of Roger Pack Sent: Tuesday, February 27, 2018 8:03 PM To: FFmpeg user questions Subject: Re: [FFmpeg-user] 4K 60Hz Directshow Video Capture consider also libx264 "ultrafast" preset, GL! On Tue, Feb 13, 2018 at 7:57 AM, Alex P <ale...@avenview.com> 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:ffmpeg-user-boun...@ffmpeg.org] 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 > ffmpeg-user@ffmpeg.org > http://ffmpeg.org/mailman/listinfo/ffmpeg-user > > To unsubscribe, visit link above, or email > ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe". > > _______________________________________________ > ffmpeg-user mailing list > ffmpeg-user@ffmpeg.org > http://ffmpeg.org/mailman/listinfo/ffmpeg-user > > To unsubscribe, visit link above, or email > ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe". > _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe". _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
