[FFmpeg-devel] [PATCH] jp2 image2 muxer

[Baptiste Coudurier]

Hi Michael,

Michael Niedermayer wrote:
> On Wed, Dec 17, 2008 at 12:11:38AM -0800, Baptiste Coudurier wrote:
>> Hi,
>> 
>> $subject,
>> 
>> You can extract jp2 files from .R3D files and also from .mov/.mj2
>> 
>> ffmpeg -i <file.mj2/.r3d> -vcodec copy test%d.jp2
> [...]
>> @@ -358,6 +359,29 @@ url_fclose(pb[1]); url_fclose(pb[2]); }else{ +
>> if(codec->codec_id == CODEC_ID_JPEG2000){ +            AVStream *st
>> = s->streams[0]; +            if(st->codec->extradata_size > 8 && +
>> AV_RL32(st->codec->extradata+4) == MKTAG('j','p','2','h')){ +
>> if(pkt->size < 8 || AV_RL32(pkt->data+4) != MKTAG('j','p','2','c'))
>>  +                    goto error; +                put_be32(pb[0],
>> 12); +                put_tag (pb[0], "jP  "); +
>> put_be32(pb[0], 0x0D0A870A); // signature +
>> put_be32(pb[0], 20); +                put_tag (pb[0], "ftyp"); +
>> put_tag (pb[0], "jp2 "); +                put_be32(pb[0], 0); +
>> put_tag (pb[0], "jp2 "); +                put_buffer(pb[0],
>> st->codec->extradata, st->codec->extradata_size); +
>> }else if(pkt->size < 8 || +
>> (!st->codec->extradata_size && +
>> AV_RL32(pkt->data+4) != MKTAG('j','P',' ',' '))){ // signature +
>> error: +                av_log(s, AV_LOG_INFO, "malformated
>> jpeg2000 codestream\n"); +                return -1; +            }
>>  +        }
> 
> The thing ive used image2 for most often is debuging. this code makes
> image2 unuseable for debuging jpeg2k, because what it writes is not
> what is in the packets besides it even refuses malformated packets,
> which is desireable if one wants actual j2k files but not when one 
> like a developer wants to look at the output of a buggy demuxer.
> 
> maybe a "rawframes" demuxer could be added that did what image2 does
> just without such modifications. Or the code could be moved to a
> bitstream filter ... sadly that brings back the problem of auto
> loading bsfs.

I undestand, I changed the check to use av_str2id which will match
CODEC_ID_JPEG2000 when ".jp2" extension is used, in this case I think
the code makes all its sense, since user want valid .jp2 files.

What do you think ?

-- 
Baptiste COUDURIER                              GnuPG Key Id: 0x5C1ABAAA
Key fingerprint                 8D77134D20CC9220201FC5DB0AC9325C5C1ABAAA
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