[FFmpeg-devel] [PATCH] Add documentation that seeking is done by DTS and not PTS

[Michael Niedermayer]

On Wed, May 02, 2012 at 10:49:25AM +0200, Robert Krüger wrote:
> On Mon, Apr 30, 2012 at 3:53 PM, Michael Niedermayer <michaelni at gmx.at> wrote:
> > On Fri, Apr 13, 2012 at 06:57:07PM +0200, Michael Niedermayer wrote:
> >> On Fri, Apr 13, 2012 at 10:49:44AM -0600, Michael Bradshaw wrote:
> >> > On Thu, Apr 12, 2012 at 9:48 AM, Michael Niedermayer <michaelni at gmx.at>wrote:
> >> >
> >> > > On Thu, Apr 12, 2012 at 07:42:42AM -0600, Michael Bradshaw wrote:
> >> > > > On Thu, Apr 12, 2012 at 6:40 AM, Michael Niedermayer <michaelni at gmx.at
> >> > > >wrote:
> >> > > >
> >> > > > > On Wed, Apr 11, 2012 at 10:22:59PM -0600, Michael Bradshaw wrote:
> >> > > > > > Signed-off-by: Michael Bradshaw <mbradshaw at sorensonmedia.com>
> >> > > > > > ---
> >> > > > > >  libavformat/avformat.h |    5 +++++
> >> > > > > >  1 files changed, 5 insertions(+), 0 deletions(-)
> >> > > > > >
> >> > > > > > diff --git a/libavformat/avformat.h b/libavformat/avformat.h
> >> > > > > > index 5a11fdc..e4ec415 100644
> >> > > > > > --- a/libavformat/avformat.h
> >> > > > > > +++ b/libavformat/avformat.h
> >> > > > > > @@ -1456,6 +1456,9 @@ int av_read_frame(AVFormatContext *s, AVPacket
> >> > > > > *pkt);
> >> > > > > >  /**
> >> > > > > >   * Seek to the keyframe at timestamp.
> >> > > > > >   * 'timestamp' in 'stream_index'.
> >> > > > > > + *
> >> > > > > > + * Note that seeking is done by DTS and not by PTS.
> >> > > > >
> >> > > > > this is not true for all demuxers, nut should be seeking to pts for
> >> > > > > example.
> >> > > > >
> >> > > >
> >> > > > Oh great, so this is even more confusing than I thought ;). Is there any
> >> > > > way of knowing if a demuxer seeks by DTS or by PTS? Should I change the
> >> > > > patch to say something along the lines of:
> >> > > >
> >> > > > "Note that some demuxers seek by DTS and some seek by PTS."?
> >> > >
> >> > > we could add a flag that specifies if a demuxer is able to seek by pts.
> >> >
> >> >
> >> > Would this be part AVInputFormat.flags? I would be in favor of having a
> >> > flag that allows the user to know if seeking is done by PTS or DTS.
> >>
> >> yes, that was the idea
> >
> > flag added locally, will be in my next git push
> > feel free to add the flag to demuxers to which it applied
> >
> > Thanks
> 
> great! just out of curiosity and because it's related to my question
> regarding index entry timestamp semantics a few months ago: is there
> any use case where it makes sense from an API user perspective to seek
> by DTS or is this something that just happened because it is easier
> from the implementation point of view for some containers? I'm not
> trying to criticize anything. I'm merely trying to understand because
> I have not come across a reason to seek by DTS.

I dont see an immedeate reason either, maybe reimar knows one ..

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I am the wisest man alive, for I know one thing, and that is that I know
nothing. -- Socrates
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 198 bytes
Desc: Digital signature
URL: <http://ffmpeg.org/pipermail/ffmpeg-devel/attachments/20120502/2ad57e60/attachment.asc>