<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=gb2312"> <html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:st1="urn:schemas-microsoft-com:office:smarttags" xmlns="http://www.w3.org/TR/REC-html40"> <head> <meta name=Generator content="Microsoft Word 11 (filtered medium)"> <o:SmartTagType namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="City"/> <o:SmartTagType namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="place"/> <o:SmartTagType namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="PersonName"/>  <style>  </style> </head> <body lang=ZH-CN link=blue vlink=blue> <div class=Section1> But the timestamp will be mess.<o:p></o:p> You could get some frames in a short time, then idle some time, then another some frames.<o:p></o:p> <o:p> </o:p> <o:p> </o:p> <div> <div class=MsoNormal align=center style='text-align:center'> <hr size=2 width="100%" align=center tabindex=-1> </div> From: thiagossantos@gmail.com [mailto:thiagossantos@gmail.com] Sent: 2009年11月18日 7:19 To: <st1:PersonName w:st="on">Discussion of the development of GStreamer</st1:PersonName> Subject: Re: [gst-devel] How to control pipeline frame rate when my camera needs some time to get one frame data<o:p></o:p> </div> <o:p> </o:p> <o:p> </o:p> <div> On Tue, Nov 17, 2009 at 8:11 PM, Zhao, Halley <<a href="mailto:halley.zhao@intel.com">halley.zhao@intel.com</a>> wrote:<o:p></o:p> <div link=blue vlink=purple> <div> Hi all:<o:p></o:p> My camera needs ~20ms to get one frame of data, and a video sink in the pipeline needs ~4ms to render it.<o:p></o:p> But when I set pipeline fps to 35, I only got 20 fps (calculate by GST CLOCK). CPU is not busy at this time, only 60%.<o:p></o:p>  <o:p></o:p> I guess the reason is following:<o:p></o:p> When we got nth frame at time 0, gst framework schedule to get next frame after 30ms (1000/35), and when the camera src element got scheduled to create one frame, it needs 20ms to get the data.<o:p></o:p> Then the time between n frame and n+1 frame is 30+20=50ms, so I just got 20 fps.<o:p></o:p> Is my assumption right?<o:p></o:p> If yes, is there any way to adjust it?<o:p></o:p> </div> </div> <div> You can speed it up by adding a queue right after your source element. It will create another thread to push data after it, the thread used to request a frame from the camera will quickly return to the source and it will request another one.  <o:p></o: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 link=blue vlink=purple> <div>  <o:p></o:p> I had though to create another thread inside camera source, and prepare the frame data in a buffer before it is schedule.<o:p></o:p> However, I think it is hack, and make timestamp differ. I think it’s better settled inside gst framework. <o:p></o:p>  <o:p></o:p>  <o:p></o:p> <div> ZHAO, Halley (Aihua)<o:p></o:p> Email: halley.zhao@intel.com<o:p></o:p> Tel: +86(21)61166476<o:p></o:p> iNet: 8821-6476<o:p></o:p> SSG/OTC/Moblin 3W038 Pole: F4<o:p></o:p> </div>  <o:p></o:p> </div> </div> ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free <st1:City w:st="on"><st1:place w:st="on">Crystal</st1:place></st1:City> Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with <st1:City w:st="on"><st1:place w:st="on">Crystal</st1:place></st1:City> Reports now.  <a href="http://p.sf.net/sfu/bobj-july" target="_blank">http://p.sf.net/sfu/bobj-july</a> _______________________________________________ gstreamer-devel mailing list <a href="mailto:gstreamer-devel@lists.sourceforge.net">gstreamer-devel@lists.sourceforge.net</a> <a href="https://lists.sourceforge.net/lists/listinfo/gstreamer-devel" target="_blank">https://lists.sourceforge.net/lists/listinfo/gstreamer-devel</a><o:p></o:p> </blockquote> </div> -- Thiago Sousa <st1:City w:st="on"><st1:place w:st="on">Santos</st1:place></st1:City><o:p></o:p> </div> </body> </html>