[FFmpeg-devel] [PATCH] matroskadec, matroskadec, srtenc: Read/Write duration for subtitles.

Michael Niedermayer michaelni at gmx.at
Sun Aug 5 00:38:23 CEST 2012


On Sat, Aug 04, 2012 at 03:08:23PM -0700, Philip Langdale wrote:
> Ok, let's get this sorted out once and for all.
> 
> I can't see any reason to manipulate the convergence duration instead.
> These subtitle packets are the moral equivalent of keyframes, and
> while the documentation says it should be used for 'some types of
> subtitles', I don't see how Matroska or srt text subtitles fall into
> that category.
> 
> The original claim was that convergence_duration was needed to avoid
> overflow on long duration subtitles. This claim seems questionable.
> If we consider the typical timebase of 1/1000, that still allows
> for a duration of 8 years. For a 1/1000000 timebase, you still get
> a 71 minute maximum duration, so I'm not sure where this claim
> originated from. Only if you go down to a 1ns timebase do you end
> up with a short max duration of ~4 seconds. Am I missing something?
> 
> This change is backward compatible by reading and writing
> convergence_duration. I don't know if that's really necessary.
> 
> Signed-off-by: Philip Langdale <philipl at overt.org>
> ---
>  libavformat/matroskadec.c |    5 +++--
>  libavformat/matroskaenc.c |    6 ++++--
>  libavformat/srtenc.c      |    4 +++-
>  3 files changed, 10 insertions(+), 5 deletions(-)

the patch should be ok

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

The educated differ from the uneducated as much as the living from the
dead. -- Aristotle 
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