[FFmpeg-devel] [PATCH] lavf: accept time base from untrusted codecs if it matches timings

[Michael Niedermayer]

On Tue, Feb 01, 2011 at 12:15:34PM -0500, Ronald S. Bultje wrote:
> Hi,
> 
> On Tue, Feb 1, 2011 at 11:49 AM, Anssi Hannula <anssi.hannula at iki.fi> wrote:
> > On 01.02.2011 18:10, Ronald S. Bultje wrote:
> >> On Sun, Jan 30, 2011 at 2:33 PM, Anssi Hannula <anssi.hannula at iki.fi> wrote:
> >>> @@ -627,6 +627,8 @@ typedef struct AVStream {
> >>> ? ? ? ? int64_t last_dts;
> >>> ? ? ? ? int64_t duration_gcd;
> >>> ? ? ? ? int duration_count;
> >>> + ? ? ? ?int codec_tb_matches_dts;
> >>> + ? ? ? ?double codec_tb_dur_error;
> >>> ? ? ? ? double duration_error[MAX_STD_TIMEBASES];
> >>> ? ? ? ? int64_t codec_info_duration;
> >>> ? ? } *info;
> >>
> >> These are only used in av_find_stream_info(), adding them to AVStream
> >> in the middle breaks ABI and increases size for something that I don't
> >> think should be in there. Can you locally allocate and free an array
> >> instead, or create a AVFindStreamInfo array for these kind of temp
> >> values to be shared between functions?
> >
> > They are not directly in AVStream and do not increase the size of
> > AVStream nor change the API.
> >
> > Here's a longer excerpt from the above section (before the patch):
> >
> > ? ?/**
> > ? ? * Stream informations used internally by av_find_stream_info()
> > ? ? */
> > #define MAX_STD_TIMEBASES (60*12+5)
> > ? ?struct {
> > ? ? ? ?int64_t last_dts;
> > ? ? ? ?int64_t duration_gcd;
> > ? ? ? ?int duration_count;
> > ? ? ? ?double duration_error[MAX_STD_TIMEBASES];
> > ? ? ? ?int64_t codec_info_duration;
> > ? ?} *info;
> 
> Oh right it's a pointer. I still consider it ugly, ohwell if that's
> how it works now then I guess it's OK.

so how would you do it non ugly?

This kind of comments remind me of mplayer, people also said "ugg ugly"
then fixed it to be pretty but it stoped working bcause the ugly was
actually the cleanest way that worked people just didnt understand it

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

it is not once nor twice but times without number that the same ideas make
their appearance in the world. -- Aristotle
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