On Tue, Feb 19, 2008 at 11:51:40PM -0500, Rich Felker wrote:
On Wed, Feb 20, 2008 at 05:23:14AM +0100, Michael Niedermayer wrote:
Hi
When we designed the pts->dts reorder algorithm we considered arbitrary frame reorderings, but there was something we missed, that are mixes of frame and field pictures, like:
i1 p2 P3 p4 P5 p7 P8 (lower case is a field, upper is a frame) PTS 2 3 4 6 7 9 10 DTS 0 1 2 4 5 7 8
As you can see no reordering of PTS can result in the DTS values.
I'm confused by this example. As there are no B frames, dts==pts is just fine.
Fine in what respect? Certainly not fine in the respect of being a valid decoding timestamp for an mpeg2 decoder. Anyway after some sleep it seems the example above is invalid as mpeg2 says: "If field pictures are used then they shall occur in pairs" This also gives us an easy solution, just put both fields in a single nut frame. I also should likely try that in ffmpeg the code i commited yesterday to interpolate field picture timestamps is ugly, though it should work with any possible mixture ... also here are a few examples with b frames: i p P B B B B 0 1 10 2 4 6 8 - - 0 2 4 6 8 i P p B B B B (invalid in mpeg2 i dunno about h.264) 0 1 11 2 4 6 8 - - 1 2 4 6 8 I p p B B B B 0 10 11 2 4 6 8 - 0 1 2 4 6 8 i p p p B B B B 0 1 10 11 2 4 6 8 - - 0 1 2 4 6 8 I P b b b b b b b b 0 10 2 3 4 5 6 7 8 9 - 0 2 3 4 5 6 7 8 9 [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Frequently ignored awnser#1 FFmpeg bugs should be sent to our bugtracker. User questions about the command line tools should be sent to the ffmpeg-user ML. And questions about how to use libav* should be sent to the libav-user ML.