On Monday, April 17, 2017 6:22:18 AM CDT Erik Slagter wrote: > > according to mp4box tutorials that I have read about making mpeg-dash, I > > know that I have to set keyint and minkey int equal and also related to > > segment duration. so I tries using min-keyint=100, but the result video > > had > > the min-keyint=51 > > Do the tutorials also explain why you would ever want to use a braindead > (!) fixed gop size in the first place? > > I could imagine a requirement for a closed gop type, but really not why > you'd want to be gop's always exactly the same length, it's making > encoding really inefficient.
If you encode a DASH stream with multiple representations (dynamic streaming with multiple resolutions / bitrates) you have no way to ensure that the encoders for the different resolutions and / or bitrates set the exact same GOP boundaries and segmentation on the same frames. Without some way to slave encoder processes to one master encoder process with respect to GOP, frame- type decisions and segmentation, locking down the GOP to a set size is the only way to ensure that. Would be awesome if ffmpeg / x264 developed a way to provide that master - slave IPC between different encode sub-processes. May not apply to this specific situation, but I think that is the thinking behind the strict GOP size recommendation. -Reuben _______________________________________________ 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".
