[FFmpeg-devel] [PATCH] VC-1 SP/MP test bitstreams demuxer

[Michael Niedermayer]

On Sat, Jan 26, 2008 at 07:48:08PM +0200, Kostya wrote:
> On Sat, Jan 26, 2008 at 05:49:04PM +0100, Michael Niedermayer wrote:
> > On Sat, Jan 26, 2008 at 05:46:01PM +0200, Kostya wrote:
> > > $subj, taken from 2006 SoC project and updated for current API.
> > 
> [review skipped]
> 
> Here is simplified version, now without context and redundant copies.
> Other stuff is simplified a bit too.
>  
> > [...]
> > -- 
> > Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

> Index: libavformat/vc1test.c
> ===================================================================
> --- libavformat/vc1test.c	(revision 0)
> +++ libavformat/vc1test.c	(revision 0)
> @@ -0,0 +1,95 @@
[...]
> +/**
> + * @file vc1test.c
> + * VC1 test bitstreams file demuxer
> + * by Konstantin Shishkov
> + * Format specified in SMPTE standard 421 Annex L
> + */
> +
> +#include "avformat.h"
> +
> +#define VC1_EXTRADATA_SIZE 4
> +
> +static int vc1t_probe(AVProbeData *p)
> +{
> +    if (p->buf[3] != 0xC5 && AV_RL32(&p->buf[4]) != 4)
> +        return 0;
> +
> +    return AVPROBE_SCORE_MAX;
> +}
> +
> +static int vc1t_read_header(AVFormatContext *s,
> +                           AVFormatParameters *ap)
> +{
> +    ByteIOContext *pb = s->pb;
> +    AVStream *st;
> +
> +    url_fskip(pb, 3); //frame count, little-endian
> +    if(get_byte(pb) != 0xC5 || get_le32(pb) != 4)
> +        return -1;
> +
> +    /* init video codec */
> +    st = av_new_stream(s, 0);
> +    if (!st)
> +        return -1;
> +
> +    st->codec->codec_type = CODEC_TYPE_VIDEO;
> +    st->codec->codec_id = CODEC_ID_WMV3;
> +
> +    st->codec->extradata = av_malloc(VC1_EXTRADATA_SIZE);
> +    st->codec->extradata_size = VC1_EXTRADATA_SIZE;
> +    get_buffer(pb, st->codec->extradata, VC1_EXTRADATA_SIZE);
> +    st->codec->height = get_le32(pb);
> +    st->codec->width = get_le32(pb);
> +    if(get_le32(pb) != 0xC)
> +        return -1;
> +    url_fskip(pb, 8);

> +    av_set_pts_info(st, 33, 1, get_le32(pb));
                           ^^
wrong


> +
> +    return 0;
> +}
> +

> +static int vc1t_read_packet(AVFormatContext *s,
> +                           AVPacket *pkt)
> +{
> +    ByteIOContext *pb = s->pb;
> +    int frame_size;
> +    int keyframe = 0;
> +
> +    frame_size = get_le24(pb);
> +    if(get_byte(pb) & 0x80)
> +        keyframe = 1;

> +    url_fskip(pb, 4); // timestamp in ms

yes thanks you, i just wanted to ask if this is a timestamp but forgot
in the last review ...
please set pkt->dts or pts accordingly


> +    if(av_get_packet(pb, pkt, frame_size) < 0)
> +        return AVERROR(EIO);
> +    pkt->flags |= keyframe ? PKT_FLAG_KEY : 0;
> +
> +    return pkt->size;
> +}
> +
> +AVInputFormat vc1t_demuxer = {
> +    "vc1test",
> +    "VC1 test bitstream format",
> +    0,
> +    vc1t_probe,
> +    vc1t_read_header,
> +    vc1t_read_packet,
> +};

does seeking work?
if no try setting AVFMT_GENERIC_INDEX and try again
if still not, check if the generic code builds the index properly
and fix it, this should be just a 1 or 2 line fix in utils.c

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

I am the wisest man alive, for I know one thing, and that is that I know
nothing. -- Socrates
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