Cai, Xin wrote: > hi guys > So I have been playing around with AV library for a few days and so far I > gotten it to grab video from an IP camera and convert it to mpeg4 and write > it to the disk. > My code basically works by > 1. grab frame from Video and decode it by calling avcodec_decode_video > 2. encode the frame by calling avcodec_encode_video > 3. write the frame to disk using av_write_frame > > Now I want to be able to further control the quality of the video I am > writing to the disk. So I would like to know how can I change the frame rate > of the video being written to the disk? Now base on the output_example.c file > I thought that it is controlled > by the AVstream *st->codec->time_base.den field. But when I tried to set > that, all it did is slow down the rate in which the video is being played at. > So lets say I have a 5 second video at 30 fps, now it plays it at 2fps but it > takes 15 * 5 seconds to finish playing. So how can I get it to drop frames? > Isn't is as simple as to omit the 14 images in between ? So instead of writing 30 images/sec to disk you would only write 2 of them. This way you would get back to 'real time' display when playing the video. > My second question is, I also want to be able to strip away color information > and turn the video to black and white. How would I do that? Thanks > > Xin Cai > > > > > > _______________________________________________ > libav-user mailing list > [email protected] > https://lists.mplayerhq.hu/mailman/listinfo/libav-user >
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