[Ffmpeg-devel] [BUG] no video transcoding
Tue Apr 24 02:29:37 CEST 2007
On Mon, Apr 23, 2007 at 04:58:00PM +0200, Baptiste Coudurier wrote:
> Michael Niedermayer wrote:
> > Hi
> > On Mon, Apr 23, 2007 at 10:55:06AM -0000, Wolfram Gloger wrote:
> >> Hi,
> >>> to comment a little more on this as it seem to be a popular bug ;)
> >>> On Sun, Apr 15, 2007 at 08:13:37AM -0000, Wolfram Gloger wrote:
> >>> [...]
> >>>> Ok that's probably true -- although I maintain the patch is correct,
> >>> no it is not, cur_dts was approximately correct before and completely
> >>> wrong after the patch
> >> How so? cur_dts was set to some more or less random packet's dts
> >> that was the last one parsed in av_find_stream_info().
> > and your proposed patch sets it to the first dts from av_find_stream_info()
> > that is equally random
> > audio time stamp ?, ?, ?, 5, ?, ?, 123456, 123457, ...
> > video time stamp ?, ?, ?, ?, ?, ?, 123456, 123457, ...
> > timestamp discontinuity ^
> > the first dts here would be 5 and 123456
> > filling things in would lead to something like:
> > audio time stamp 5, 6, 7, 5, 6, 7, 123456, ...
> > video time stamp 123456, 123457, 123458, 123459, 123460, 123461, 123456, ...
> > that is not better than what you get with the last dts, actually its
> > worse
> >> Then the packet queue is flushed and the next packet read has a
> >> (sometimetimes significantly) smaller dts value.
> >> This leads to a hard error (dts < cur_dts) for valid DVB streams.
> >> It is just a matter of luck if you don't hit this situation.
> >> After the patch, cur_dts becomes AV_NO_PTS_VALUE -- how can that
> >> be "completely wrong". Please elaborate.
> > its not completly wrong on its own but in combination with all the other
> > code it is
> > [...]
> >> I suspect that reverting 8465 will hide the problem, but
> >> please give me until tonight when I will allocate some time
> > time is no problem, i can wait, i just want a clean solution ...
> Seek regression tests fails with the latest patch posted:
> @@ -3302,7 +3302,7 @@
> ret:-1 st:-1 ts:-0.645825 flags:1
> -ret: 0 st: 0 dts:95443.677689 pts:95443.717689 pos:-1 size:24921 flags:1
> +ret: 0 st: 0 dts:95443.677689 pts:0.000000 pos:-1 size:24921 flags:1
> ret: 0 st:-1 ts:-1.000000 flags:0
is better IMHO than
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
In a rich man's house there is no place to spit but his face.
-- Diogenes of Sinope
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