On Wed, 17 Jul 2019 at 11:41, Paul Cruickshank <[email protected]> wrote:
> Hi, > > We're working on a project to have a highly parallelized video rescaling > pipeline but we're finding that small audio and video jumps are being > introduced into the video when we put the video back together. Can anyone > point out anything we're doing wrong? > > The pipeline has 3 stages. First we split the video using the segment muxer > $ ./ffmpeg -i samples/2160p-h264-aac-20mbs-2m.mp4 -muxdelay 0 -muxpreload 0 > -c copy -copyts -f segment -fflags > +genpts -segment_time 4 -segment_format mpegts out/segments/%04d.ts > > Then we change the scale for each of the segments using: > $ ./ffmpeg -i out/segments/0000.ts -muxdelay 0 -vf scale=1920:1080 -c:v > libx264 -g 96 -keyint_min 96 -sc_threshold 0 -profile:v main -c:a aac > -copyts out/segments/out00.ts > > And then we rejoin > $ ./ffmpeg -i > "concat:out/segments/out00.ts|out/segments/out01.ts|out/segments/out02.ts" > -c copy -copyts out/transcoded.mp4 > > The jumps seem to correlate to the segment boundaries. The jumps are even > worse if we have to change audio codec from ac3 to aac in the middle > transcode stage. It we skip the middle rescaling stage then we don't get > any jumps in the output video so it's something that's going wrong in that > command. > > For reference the commands are using ffmpeg 4.1.3 and the video I tested > the commands with > > http://downloads.4ksamples.com/videos/PUPPIES%20BATH%20IN%204K%20(ULTRA%20HD)(Original_H.264-AAC)%20(4ksamples.com).mp4 > > Thanks, > Paul > > See the changes above and retest -- まさひろ はやし _______________________________________________ ffmpeg-user mailing list [email protected] https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
