ffdec_mpeg4 gets wrong frame rate from rtspsrc
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Hi~
My application gets the mpeg4 video stream from a AXIS camera and displays it on a x-window. Everything works perfectly. However, I have a problem with recording the video to the file. The problem is that ffdec_mpeg4 gets or sets (not sure who has set) wrong frame rate. The sdp from rtspsrc said, the frame rate is 30/1 (sdp attribute belonged to a media "a=framerate: 30.0"). However, the source pad of ffdec_mpeg4 has frame rate of 100/1. So, When I record the stream and plays it, it runs approximately three times faster than what it is suppoesed to do. I think either one of upstream elements, rtspsrc and rtpmp4vdepay, or ffdec_mpeg4 is doing something wrong. Do you guys think it it a bug? What's you think about it? Thanks, Justin ------------------------------------------------------------------------------ Enter the BlackBerry Developer Challenge This is your chance to win up to $100,000 in prizes! For a limited time, vendors submitting new applications to BlackBerry App World(TM) will have the opportunity to enter the BlackBerry Developer Challenge. See full prize details at: http://p.sf.net/sfu/Challenge _______________________________________________ gstreamer-devel mailing list [hidden email] https://lists.sourceforge.net/lists/listinfo/gstreamer-devel |
Re: ffdec_mpeg4 gets wrong frame rate from rtspsrc
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Hash: SHA1 joh a écrit : > Hi~ > > My application gets the mpeg4 video stream from a AXIS camera and > displays it on a x-window. Everything works perfectly. However, I have a > problem with recording the video to the file. The problem is that > ffdec_mpeg4 gets or sets (not sure who has set) wrong frame rate. The > sdp from rtspsrc said, the frame rate is 30/1 (sdp attribute belonged to > a media "a=framerate: 30.0"). However, the source pad of ffdec_mpeg4 has > frame rate of 100/1. So, When I record the stream and plays it, it runs > approximately three times faster than what it is suppoesed to do. > > I think either one of upstream elements, rtspsrc and rtpmp4vdepay, or > ffdec_mpeg4 is doing something wrong. Do you guys think it it a bug? > What's you think about it? don't know whether it's a bug or not, but you should try to define caps with a capsfilter element like capsfilter caps="framerate=(fraction)30/1" Florian -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iEYEARECAAYFAkpkPVIACgkQO8DE9K7b371s/QCgjgAYW97nD29v1auVhIQ+0XwW ZqUAoLCRsv8tnRYzzgLLMFoXXGt7jBN2 =Shzy -----END PGP SIGNATURE----- ------------------------------------------------------------------------------ Enter the BlackBerry Developer Challenge This is your chance to win up to $100,000 in prizes! For a limited time, vendors submitting new applications to BlackBerry App World(TM) will have the opportunity to enter the BlackBerry Developer Challenge. See full prize details at: http://p.sf.net/sfu/Challenge _______________________________________________ gstreamer-devel mailing list [hidden email] https://lists.sourceforge.net/lists/listinfo/gstreamer-devel |
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Thank you for the answer. I've already add the capsfilter to fix the problem, but my app. should support many different types of sources, so I can't hard code the frame rate.
Anyway, the videosink plays well with the decoder caps of framerate=100/1. I think it means videosink does not look at the caps to play the stream, but jpegenc or avimux does look at the framerate for recording. I've investigated source code, but I coudn't find where the 100/1 came from. The truth is that rtspsrc doesn't even care about "a=framerate..." field to create cap, and it seems like not a mandatory attribute. Anybody can tell me what how mp4vdepay or ffdec_mpeg4 sets frame rate? Thank you in advance! Justin Is there anybody who can judge that this is a bug or not? On Mon, Jul 20, 2009 at 2:48 AM, florian iragne <[hidden email]> wrote: -----BEGIN PGP SIGNED MESSAGE----- ------------------------------------------------------------------------------ Enter the BlackBerry Developer Challenge This is your chance to win up to $100,000 in prizes! For a limited time, vendors submitting new applications to BlackBerry App World(TM) will have the opportunity to enter the BlackBerry Developer Challenge. See full prize details at: http://p.sf.net/sfu/Challenge _______________________________________________ gstreamer-devel mailing list [hidden email] https://lists.sourceforge.net/lists/listinfo/gstreamer-devel |
Re: ffdec_mpeg4 gets wrong frame rate from rtspsrc
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On Monday 20 July 2009 18:11:26 joh wrote:
> I've investigated source code, but I coudn't find where the 100/1 came > from. The truth is that rtspsrc doesn't even care about "a=framerate..." > field to create cap, and it seems like not a mandatory attribute. > > Anybody can tell me what how mp4vdepay or ffdec_mpeg4 sets frame rate? I think it's the framerate that is set by the MPEG4 stream itself. Try running with --gst-debug=ffmpeg:5 and look for 'Using framerate from codec'. If that is there, it means the MPEG4 stream specifies a framerate of 100fps. I had something similar with Sony's MPEG4 cameras. It would surprise me that Axis does things the wrong way, but it is possible I guess... Regards, Arnout -- Arnout Vandecappelle arnout at mind be Senior Embedded Software Architect +32-16-286540 Essensium/Mind http://www.mind.be G.Geenslaan 9, 3001 Leuven, Belgium BE 872 984 063 RPR Leuven LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle GPG fingerprint: D206 D44B 5155 DF98 550D 3F2A 2213 88AA A1C7 C933 ------------------------------------------------------------------------------ _______________________________________________ gstreamer-devel mailing list [hidden email] https://lists.sourceforge.net/lists/listinfo/gstreamer-devel |
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Hi Amout,
Thank you for your answer! I've just looked at the debug messages, and found what you mentioned. Below are the part of log. By the way, can you explain how I can watch the video in normal speed? Does it mean that ffmpeg duplciates frames to satisfy the frame rate what it belives? Regards, Justin ------------------------------------------------------------------------------------------- gstffmpegdec.c:714:gst_ffmpegdec_setcaps:<ffdec_mpeg40> forcing 25/1 framerate gstffmpegdec.c:744:gst_ffmpegdec_setcaps:<ffdec_mpeg40> Using framerate from codec . . ffmpeg gstffmpegdec.c:1130:gst_ffmpegdec_negotiate:<ffdec_mpeg40> Renegotiating video from 0x0@ -1/-1 fps to 640x480@ -1/0 fps ffmpeg gstffmpegcodecmap.c:1724:gst_ffmpeg_codectype_to_video_caps: context:0x9c81c00, codec_id:13, encode:0, codec:(nil) ffmpeg gstffmpegcodecmap.c:186:gst_ff_vid_caps_new: context:0x9c81c00, codec_id:13, mimetype:video/x-raw-yuv gstffmpegcodecmap.c:1602:gst_ffmpeg_pixfmt_to_caps: caps for pix_fmt=0: video/x-raw-yuv, width=(int)640, height=(int)480, framerate=(fraction)100/1, format=(fourcc)I420 ------------------------------------------------------------------------------------------- On Wed, Jul 22, 2009 at 1:12 AM, Arnout Vandecappelle <[hidden email]> wrote:
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Re: ffdec_mpeg4 gets wrong frame rate from rtspsrc
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On Wednesday 22 July 2009 18:01:56 joh wrote:
> By the way, can you explain how I can watch the video > in normal speed? Does it mean that ffmpeg duplciates frames to satisfy the > frame rate what it belives? No, as long as you stay within GStreamer, the per-frame timestamps are used and the framerate doesn't really matter. It's only when you mux it into a file again that the framerate is used. Maybe you're storing it in an AVI file, that doesn't have per-frame timestamps so when you play it from the file it uses the 100fps value. You could fix the rtspsrc to extract the framerate from the SDP message... Regards, Arnout -- Arnout Vandecappelle arnout at mind be Senior Embedded Software Architect +32-16-286540 Essensium/Mind http://www.mind.be G.Geenslaan 9, 3001 Leuven, Belgium BE 872 984 063 RPR Leuven LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle GPG fingerprint: D206 D44B 5155 DF98 550D 3F2A 2213 88AA A1C7 C933 ------------------------------------------------------------------------------ _______________________________________________ gstreamer-devel mailing list [hidden email] https://lists.sourceforge.net/lists/listinfo/gstreamer-devel |
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