On Tue, Oct 22, 2013 at 12:57 PM, Carl Eugen Hoyos <[email protected]> wrote: > Robert Krüger <krueger@...> writes: > >> I just cut away everything from the file until the start >> of the packet containing the 27th frame >> (tail -c4329532 gh1_720p.mts > gh1_720p_cat.mts) and the >> resulting file decodes without artifacts using ffmpeg. > > (With or without -flags2 showall?) > >> The number of decoded frames is also as expected. So I >> think this is at least an indication that the 27th >> frame is indeed a valid random access point. > > I don't think the fact that a frame can be decoded > (correctly) implies that it is a random access point.
I thought that was the definition of it but more importantly for all practical purposes (being able to create subclips, seeking) that's what is typically the important thing but I agree that it takes more knowledge than that to change ffmpeg code in a way that reliably detects that (if possible at all). As I wrote earlier in this thread, if this is not done in ffmpeg (I am not qualified to do that in the h264 code), I will probably do that outside (parse h264 structures to build an index of random access points, if necessary applying heuristics that work for the files I am interested in). _______________________________________________ Libav-user mailing list [email protected] http://ffmpeg.org/mailman/listinfo/libav-user
