2016-10-26 23:07 GMT+02:00 Sven C. Dack <sven.c.d...@sky.com>: > On 26/10/16 20:06, Ronald F. Guilmette wrote: >> >> Apologies if this is an FAQ. >> >> I have a video with a fixed frame rate of 59.940 fps. Some of my devices >> don't cope with this very well. Thus, I'd like to convert the video to >> one with exactly half the frame rate (29.970), but preferably without >> doing any reencoding, e.g. just by stripping away every odd numbered >> frame (or every even numbered one). >> >> Is there a way to do this with ffmpeg, and if so, what is the command >> line to do it?
> this is only possible when the input is composed of absolute frames, > i.e. with Motion JPEG. Alternatives may exist (but this is impossible to know without ffmpeg -i output). > Your video will probably have been compressed with one of > the more advanced algorithms and these purposely do not treat > frames as absolute, but use their differences for their encoding. As > such can you not drop every second frame, because you don't have > full frames and dropping some of the intermediate frame information > means you lose vital information for reconstructing the frames. > > If you want to change the frame rate then you have to use the "-r" option. > For example: > $ ffmpeg -i input.mp4 -r 29.97 -c:v libx264 -y output.mp4 I do not remember a sample file for which "-r 29.97" would have been correct. Carl Eugen _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
