On Oct 16, 2013, at 8:56 AM, Bruce Wheaton <[email protected]> wrote:
> >> On Oct 16, 2013, at 8:46, Paul B Mahol <[email protected]> wrote: >>> The only workaround is to use intra-frame only compression, so all frames >>> are independent. Some codecs you listed always work that way. >> >> ffvhuff is intra only. > > I don't know that codec. I just knew it was lossless. So I guess (unless > there's a bug) the rule has an exception. Maybe the 'adaptive tables' that > google says it has adapt every 24 or so frames. Don't have the source in > front of me right now. > > But it's an FOSS project - anyone look at the code and see what's going on. I can't pick it out of the code, and the codec info says it is intra-frame only... but this paper seems to indicate that ffvhuff isn't always intra-frame only: "FFv1 [16] was also developed by the FFmpeg project and is derived from HuffYUV. The main difference is that the intra-frame coding model is limited to the median model as described above" >From COMPARISON OF LOSSLESS VIDEO CODECS FOR CROWD-BASED QUALITY ASSESSMENT ON >TABLETS Christian Keimel, Christopher Pangerl and Klaus Diepold https://mediatum.ub.tum.de/doc/1128908/1128908.pdf So - as I mentioned - videos that aren't encoded as intra-frame often have to decode a number of frames in order to get to your desired frame. As far as I know, the only way ffmpeg deals with that is by decoding all the frames from a known safe search point up until your desired frame. Bruce > >>>> Does this have anything to do with cached frames, or is that another >>>> issue? >>>> >>>> _______________________________________________ >>>> Libav-user mailing list >>>> [email protected] >>>> http://ffmpeg.org/mailman/listinfo/libav-user >> _______________________________________________ >> Libav-user mailing list >> [email protected] >> http://ffmpeg.org/mailman/listinfo/libav-user > _______________________________________________ > Libav-user mailing list > [email protected] > http://ffmpeg.org/mailman/listinfo/libav-user _______________________________________________ Libav-user mailing list [email protected] http://ffmpeg.org/mailman/listinfo/libav-user
