On Thu, Oct 06, 2016 at 10:53:14 -0300, Marcelo Boufleur wrote: > I'm not sure that what Mikhail wants really exists. If I understand > correctly, you want to retain original encoding and drop one frame every > two frames.
I understand the same thing. (Carl Eugen was concentrating on Mikhail's "not re-encoding" wording, which can of course be achieved by just decoding. ;-)) Keep every second frames without decoding them, but re-assembling them to a valid MXF. > If this would be possible, you would have to work at the DNxHD inner level, > identify each frame start/end (by headers), bit-stream copy whichever > frames you would need, and then re-generate the DNxHD layer and headers to > reflect all the changes you have made. Exactly. Since you don't want to decode (which implies re-encoding), this would be with "-c:v copy" and would effectively be a bitstream filter. I'm not aware that any such filter exists (and whether the ffmpeg devs would even consider accepting integrating such a bsf). It pure theory, this *could* even be done for more codecs than just DNxHD. > I may be wrong, but I believe with current FFmpeg implementation you can > only work either with stream copy (if you don't want to change encoding, > nor frame rate, which defies his purpose), or use the previous suggestions > to cut framerate by half, which implies on re-encoding (which again, defies > his purpose). I found the suggestion to use the concat demuxer with streamcopy very interesting. Assuming it can seek and cut precisely, that could work - again in theory. Let's experiment with that. :) Moritz _______________________________________________ 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".