[FFmpeg-devel] [PATCH] avformat/segafilmenc - set keyframe bit correctly

[Michael Niedermayer]

On Sat, May 05, 2018 at 08:09:07PM -0300, James Almer wrote:
> On 5/5/2018 8:06 PM, Michael Niedermayer wrote:
> > On Sat, May 05, 2018 at 05:16:09PM +0530, Gyan Doshi wrote:
> >> Since the muxer author hasn't made the change, the patch is submitted.
> >>
> >> Reference:
> >>
> >> http://www.ffmpeg.org/pipermail/ffmpeg-devel/2018-April/228602.html
> > 
> >>  segafilmenc.c |    2 +-
> >>  1 file changed, 1 insertion(+), 1 deletion(-)
> >> 710a71f12fae34d125a755bc0f5b290c6a6018e9  0001-avformat-segafilmenc-set-keyframe-bit-correctly.patch
> >> From 79f87ff264c2989193d5e59da8c5cf285940aa50 Mon Sep 17 00:00:00 2001
> >> From: Gyan Doshi <ffmpeg at gyani.pro>
> >> Date: Sat, 5 May 2018 17:04:53 +0530
> >> Subject: [PATCH] avformat/segafilmenc - set keyframe bit correctly
> >>
> >> As per
> >> https://web.archive.org/web/20020803104640/http://www.pcisys.net:80/~melanson/codecs/film-format.txt,
> >>
> >> the top bit of the info1 chunk is set as 1 for inter-coded frames and 0
> >> otherwise.
> >> ---
> >>  libavformat/segafilmenc.c | 2 +-
> >>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/libavformat/segafilmenc.c b/libavformat/segafilmenc.c
> >> index 5b0d7e69e8..524230e461 100644
> >> --- a/libavformat/segafilmenc.c
> >> +++ b/libavformat/segafilmenc.c
> >> @@ -69,7 +69,7 @@ static int film_write_packet_to_header(AVFormatContext *format_context, FILMPack
> >>          info1 = pkt->pts;
> >>          info2 = pkt->duration;
> >>          /* The top bit being set indicates a key frame */
> >> -        if (pkt->keyframe)
> >> +        if (!pkt->keyframe)
> >>              info1 |= (1 << 31);
> >>      }
> > 
> > Fixes to muxers and encoders should always bump the minor or micro version of
> > the lib.
> > 
> > It would also be ideal if this version is stored in the file, that way
> > demuxers/decoders can compensate for bugs in the muxer/encoder.
> > Not sure the format has a place for this?
> 
> It's a decades old format used on a few games, it's very likely it doesn't.

yes

its probably possible to detect the muxer bug without it, if someone wants to
implement it


> 
> A micro bump should be enough.

sure

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

No great genius has ever existed without some touch of madness. -- Aristotle
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