Thanks for your reply.By "control frame rate" I meant,say,the video file itself is 25fps, and I wanna play the video with the speed of 10frame/s.
Cheers 2011/12/20 Michael Chisholm <[email protected]> > I've struggled myself with this. There are a lot more framerate-related > fields than that lying around. The ones I know of (in ffmpeg 0.6.3) are > (stream=AVStream, cc=AVCodecContext): > > stream->time_base > stream->r_frame_rate > stream->avg_frame_rate > cc->time_base > cc->ticks_per_frame > > (you'd think you could maybe derive framerate from the last) I am no > expert, but my guess is that not all containers contain a framerate field > somewhere for tools to read. So libav* tries to estimate one from timing > information. E.g. in my app I can read from a udp multicast network > stream, and even for the same stream, each time I run the app, it shows a > slightly different framerate (as shown by dump_format). Maybe because it > sees a different subsequence of timestamps, or the relative distribution in > time of those timestamps might be slightly different, ... I don't know. In > my app, I settled on stream->avg_frame_rate for my purposes. > > As far as controlling it, I'm not sure what you mean... did you just want > to decode at the frame rate of the stream, or somehow manipulate the the > video to change its framerate? > > Andy > > > On 12/19/2011 1:25 AM, Yingzhou Zhang wrote: > >> hey there. >> >> I have googled a little bit,found 2 way >> 1:AVFormatContext->streams->**time_base.num/den? >> 2:AVCodecContext-> streams->r_frame_rate? >> >> However the output of the 2 ways are not the same?? >> >> Could you tell me what is the exact way to get frame_rate and how to >> control it when decoding video? >> >> Thanks a lot >> >> >> >> ______________________________**_________________ >> Libav-user mailing list >> [email protected] >> http://ffmpeg.org/mailman/**listinfo/libav-user<http://ffmpeg.org/mailman/listinfo/libav-user> >> > > ______________________________**_________________ > Libav-user mailing list > [email protected] > http://ffmpeg.org/mailman/**listinfo/libav-user<http://ffmpeg.org/mailman/listinfo/libav-user> > -- --------------------- Best Regards
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