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

James Almer jamrial at gmail.com
Sun May 6 02:09:07 EEST 2018


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.

A micro bump should be enough.

> 
> Thanks
> 
> [...]
> 
> 
> 
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