<div dir="auto"><div> <div class="gmail_quote"><div dir="ltr" class="gmail_attr">Le lun. 7 nov. 2022, 10 h 50, Christian Hattenberger <<a href="mailto:christian.hattenberger@gmail.com">christian.hattenberger@gmail.com</a>> a écrit : </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div lang="DE" link="blue" vlink="purple"><div class="m_1142378048348340693WordSection1">Thnx I understand now the dmabuff problem with the v4l2loopback driver, but why is vaapi decode slower than sw decoder with memcopy?</div></div></blockquote></div></div><div dir="auto"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div lang="DE" link="blue" vlink="purple"><div class="m_1142378048348340693WordSection1"> gst-launch-1.0 filesrc location=/mnt/DATA/tearing.mp4 ! qtdemux ! vaapih264dec ! queue ! fpsdisplaysink video-sink="xvimagesink" sync=false text-overlay=trueis playing with 9fps gst-launch-1.0 filesrc location=/mnt/DATA/tearing.mp4 ! qtdemux ! avdec_h264 ! queue ! fpsdisplaysink video-sink="xvimagesink" sync=false text-overlay=trueis playing with 45fps</div></div></blockquote></div></div><div dir="auto"> </div><div dir="auto">There is more the one possible explanation. One is that GPU memory is often setup without cpu cache, so they stay coherent. Read and writes are then over 20x slower.</div><div dir="auto"> </div><div dir="auto">avdec_h264 do direct decoder into xv allocated memory, this gives an important boost. The decoder is multithreaded, so it can be very fast. He decoders are steady, but they are not fast.</div><div dir="auto"> </div><div dir="auto">The fallback in your va driver to download the images and convert the to a linear representation might be entirely software, and possibly using uncached read/writes.</div><div dir="auto"> </div><div dir="auto"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div lang="DE" link="blue" vlink="purple"><div class="m_1142378048348340693WordSection1"> Von: Nicolas Dufresne <<a href="mailto:nicolas@ndufresne.ca" target="_blank" rel="noreferrer">nicolas@ndufresne.ca</a>> Gesendet: Montag, 7. November 2022 02:56 An: Christian Hattenberger <<a href="mailto:christian.hattenberger@gmail.com" target="_blank" rel="noreferrer">christian.hattenberger@gmail.com</a>> Cc: Discussion of the development of and with GStreamer <<a href="mailto:gstreamer-devel@lists.freedesktop.org" target="_blank" rel="noreferrer">gstreamer-devel@lists.freedesktop.org</a>> Betreff: Re: Why is connecting vaapi decoder to v4l2sink stuttering? <div><div> <div><div>Le dim. 6 nov. 2022, 10 h 22, Christian Hattenberger <<a href="mailto:christian.hattenberger@gmail.com" target="_blank" rel="noreferrer">christian.hattenberger@gmail.com</a>> a écrit :</div><blockquote style="border:none;border-left:solid #cccccc 1.0pt;padding:0cm 0cm 0cm 6.0pt;margin-left:4.8pt;margin-right:0cm"><div><div>If I use vaapipostproc in the chain with vaapisink it seems ok, so I think it does dmabuff, but when I use io-mode=dmabuf-import with v4l2sink I get “Failed to allocated required memory” gst-launch-1.0 filesrc location=/mnt/DATA/tearing.mp4 ! decodebin ! v4l2sink io-mode=dmabuf-import device=/dev/video10 … 0:00:00.376954941 18843 0x7f4d44041460 ERROR v4l2allocator gstv4l2allocator.c:740:gst_v4l2_allocator_start:<v4l2sink0:pool1:sink:allocator> error requesting 2 buffers: Invalid argument0:00:00.377023310 18843 0x7f4d44041460 ERROR v4l2bufferpool gstv4l2bufferpool.c:920:gst_v4l2_buffer_pool_start:<v4l2sink0:pool1:sink> we received 0 buffer from device '/dev/video10', we want at least 20:00:00.377052711 18843 0x7f4d44041460 ERROR bufferpool gstbufferpool.c:559:gst_buffer_pool_set_active:<v4l2sink0:pool1:sink> start failed… v4l2-ctl -d /dev/video0 --allDriver Info: Driver name : v4l2 loopback Card type : Dummy video device (0x0000)</div></div></blockquote></div></div><div>This out-of-tree driver is incomplete, it does not support dmabuf. You are out of luck here, unless you have time to improve it.</div><div> </div><div> </div><div><div><blockquote style="border:none;border-left:solid #cccccc 1.0pt;padding:0cm 0cm 0cm 6.0pt;margin-left:4.8pt;margin-right:0cm"><div><div> Bus info : platform:v4l2loopback-000 Driver version : 5.15.49 Capabilities : 0x85208003 Video Capture Video Output Video Memory-to-Memory Read/Write Streaming Extended Pix Format Device Capabilities Device Caps : 0x05208003 Video Capture Video Output Video Memory-to-Memory Read/Write Streaming Extended Pix FormatPriority: 2Video input : 0 (loopback: ok)Video output: 0 (loopback in)Format Video Output: Width/Height : 1920/1080 Pixel Format : 'NV12' (Y/CbCr 4:2:0) Field : None Bytes per Line : 1920 Size Image : 3110400 Colorspace : Rec. 709 Transfer Function : sRGB YCbCr/HSV Encoding: ITU-R 601 Quantization : Limited Range Flags :Streaming Parameters Video Capture: Frames per second: 30.000 (30/1) Read buffers : 2Streaming Parameters Video Output: Frames per second: 30.000 (30/1) Write buffers : 2 User Controls keep_format 0x0098f900 (bool) : default=0 value=0 sustain_framerate 0x0098f901 (bool) : default=0 value=0 timeout 0x0098f902 (int) : min=0 max=100000 step=1 default=0 value=0 timeout_image_io 0x0098f903 (bool) : default=0 value=0 Von: Nicolas Dufresne <<a href="mailto:nicolas@ndufresne.ca" target="_blank" rel="noreferrer">nicolas@ndufresne.ca</a>> Gesendet: Sonntag, 6. November 2022 14:32 An: Discussion of the development of and with GStreamer <<a href="mailto:gstreamer-devel@lists.freedesktop.org" target="_blank" rel="noreferrer">gstreamer-devel@lists.freedesktop.org</a>> Cc: Christian Hattenberger <<a href="mailto:christian.hattenberger@gmail.com" target="_blank" rel="noreferrer">christian.hattenberger@gmail.com</a>> Betreff: Re: Why is connecting vaapi decoder to v4l2sink stuttering? <div><div> <div><div>Le sam. 5 nov. 2022, 13 h 16, Christian Hattenberger via gstreamer-devel <<a href="mailto:gstreamer-devel@lists.freedesktop.org" target="_blank" rel="noreferrer">gstreamer-devel@lists.freedesktop.org</a>> a écrit :</div><blockquote style="border:none;border-left:solid #cccccc 1.0pt;padding:0cm 0cm 0cm 6.0pt;margin-left:4.8pt;margin-top:5.0pt;margin-right:0cm;margin-bottom:5.0pt"><div>When I connect a vaapi decoder to v4l2sink the result is not as expected, same happens if I use autovideosink, I know for this I have to use vaapisink and it is working as expected, but is there a solution for v4l2sink? Can someone explain me the reason, is there a solution? gst-launch-1.0 filesrc location=/tmp/video.mp4 ! decodebin ! vaapipostproc ! video/x-raw,format=YUY2 ! v4l2sink device=/dev/video10 </div></blockquote></div></div><div> </div><div>Its experimental, and I am not sure if vaapipostproc does produce dmabuf in this case, but you can enable dmabuf-import on v4l2sink with property io-mode=dmabuf-import . By default, the frames are cpu copied from VA allocated memory into V4L2 allocated memory.</div><div> </div><div>Nicolas</div><div> </div></div></div></div></blockquote></div></div></div></div></div></blockquote></div></div></div>