<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=gb2312"> <meta name="Generator" content="Microsoft Word 15 (filtered medium)"> <style></style> </head> <body lang="ZH-CN" link="blue" vlink="purple"> <div class="WordSection1"> <p class="MsoNormal"><span lang="EN-US" style="font-size:10.5pt;font-family:DengXian">For video decoder output buffer, it can’t use out fence as video decoder output buffer reording. Video decoder output buffer can use input fence which from gl-render in Weston. Can this use case improve performance?<o:p></o:p></span></p> <p class="MsoNormal"><span lang="EN-US" style="font-size:10.5pt;font-family:DengXian"><o:p> </o:p></span></p> <p class="MsoNormal"><span lang="EN-US" style="font-size:10.5pt;font-family:DengXian">Regards,<o:p></o:p></span></p> <p class="MsoNormal"><span lang="EN-US" style="font-size:10.5pt;font-family:DengXian">Bing<o:p></o:p></span></p> <p class="MsoNormal"><span lang="EN-US" style="font-size:10.5pt;font-family:DengXian"><o:p> </o:p></span></p> <div> <div style="border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0cm 0cm 0cm"> <p class="MsoNormal"><b><span lang="EN-US">From:</span></b><span lang="EN-US"> gstreamer-devel <gstreamer-devel-bounces@lists.freedesktop.org> <b>On Behalf Of </b>Nicolas Dufresne<br> <b>Sent:</b> 2021</span><span style="font-family:SimSun">年</span><span lang="EN-US">1</span><span style="font-family:SimSun">月</span><span lang="EN-US">12</span><span style="font-family:SimSun">日</span><span lang="EN-US"> 22:19<br> <b>To:</b> Discussion of the development of and with GStreamer <gstreamer-devel@lists.freedesktop.org><br> <b>Subject:</b> [EXT] Re: V4L2 video decoder buffer fence<o:p></o:p></span></p> </div> </div> <p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p> <p><b><span lang="EN-US" style="color:white;background:darkred">Caution: </span></b><span lang="EN-US" style="color:white;background:darkred">EXT Email </span><span lang="EN-US"><o:p></o:p></span></p> <div> <div> <div> <p class="MsoNormal" style="margin-bottom:12.0pt"><span lang="EN-US"><o:p> </o:p></span></p> <div> <div> <p class="MsoNormal"><span lang="EN-US">Le mar. 12 janv. 2021 02 h 15, Bing Song <<a href="mailto:bing.song@nxp.com">bing.song@nxp.com</a>> a écrit :<o:p></o:p></span></p> </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> <p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">Hi,<o:p></o:p></span></p> <p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> <o:p></o:p></span></p> <p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">I want to implement v4l2 video decoder buffer fence. But I don</span><span style="font-family:DengXian">’</span><span lang="EN-US">t know why it can benefit performance? Video HW decoder is one step decode. We use Hantro video decoder. CPU SW will parser SPS/PPS and slice header. HW will decode video frame within one step decode. How dma buf fence can benefit decode performance?<o:p></o:p></span></p> </div> </div> </blockquote> </div> </div> <div> <p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p> </div> <div> <p class="MsoNormal"><span lang="EN-US">Fences alone don't save in performance. You need to combine these fences with a GPU or a display driver API to actually gain.<o:p></o:p></span></p> </div> <div> <p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p> </div> <div> <p class="MsoNormal"><span lang="EN-US">Fences in GPU and display driver are used to parallelize the processing without using extra threads, so without the context switch cost.<o:p></o:p></span></p> </div> <div> <p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p> </div> <div> <p class="MsoNormal"><span lang="EN-US">With the fences, the driver can deliver incomplete frames and program the next job without blocking. This is equivalent to adding a render delay of 1 frame, but without the full frame latency.<o:p></o:p></span></p> </div> <div> <p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p> </div> <div> <p class="MsoNormal"><span lang="EN-US">Note that fences are not yet supported in V4L2 API, there was a proposal but with some limitations (ordering and timestamp related).<o:p></o:p></span></p> </div> <div> <p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p> </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> <p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> <o:p></o:p></span></p> <p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">Regards,<o:p></o:p></span></p> <p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">Bing<o:p></o:p></span></p> </div> </div> <p class="MsoNormal"><span lang="EN-US">_______________________________________________<br> gstreamer-devel mailing list<br> <a href="mailto:gstreamer-devel@lists.freedesktop.org" target="_blank">gstreamer-devel@lists.freedesktop.org</a><br> <a href="https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.freedesktop.org%2Fmailman%2Flistinfo%2Fgstreamer-devel&data=04%7C01%7Cbing.song%40nxp.com%7C93e348942eed43cc95a208d8b70510e5%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C637460579683369061%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000&sdata=xqtnvbopz2%2BI41%2FELdtnB0JfJtJDMkMBIsdcBbu0eTs%3D&reserved=0" target="_blank">https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel</a><o:p></o:p></span></p> </blockquote> </div> </div> </div> </div> </div> </body> </html>