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libavformat
filmstripdec.c
Go to the documentation of this file.
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/*
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* Adobe Filmstrip demuxer
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* Copyright (c) 2010 Peter Ross
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "
libavutil/intreadwrite.h
"
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#include "
avformat.h
"
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#include "
internal.h
"
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#define RAND_TAG MKBETAG('R','a','n','d')
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typedef
struct
{
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int
leading
;
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}
FilmstripDemuxContext
;
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static
int
read_header
(
AVFormatContext
*s,
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AVFormatParameters
*ap)
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{
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FilmstripDemuxContext
*film = s->
priv_data
;
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AVIOContext
*pb = s->
pb
;
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AVStream
*st;
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if
(!s->
pb
->
seekable
)
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return
AVERROR
(EIO);
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avio_seek
(pb,
avio_size
(pb) - 36, SEEK_SET);
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if
(
avio_rb32
(pb) !=
RAND_TAG
) {
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av_log
(s,
AV_LOG_ERROR
,
"magic number not found"
);
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return
AVERROR_INVALIDDATA
;
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}
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st =
avformat_new_stream
(s,
NULL
);
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if
(!st)
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return
AVERROR
(ENOMEM);
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st->
nb_frames
=
avio_rb32
(pb);
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if
(
avio_rb16
(pb) != 0) {
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av_log_ask_for_sample
(s,
"unsupported packing method\n"
);
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return
AVERROR_INVALIDDATA
;
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}
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avio_skip
(pb, 2);
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st->
codec
->
codec_type
=
AVMEDIA_TYPE_VIDEO
;
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st->
codec
->
codec_id
=
CODEC_ID_RAWVIDEO
;
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st->
codec
->
pix_fmt
=
PIX_FMT_RGBA
;
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st->
codec
->
codec_tag
= 0;
/* no fourcc */
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st->
codec
->
width
=
avio_rb16
(pb);
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st->
codec
->
height
=
avio_rb16
(pb);
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film->
leading
=
avio_rb16
(pb);
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avpriv_set_pts_info
(st, 64, 1,
avio_rb16
(pb));
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avio_seek
(pb, 0, SEEK_SET);
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return
0;
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}
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static
int
read_packet
(
AVFormatContext
*s,
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AVPacket
*pkt)
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{
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FilmstripDemuxContext
*film = s->
priv_data
;
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AVStream
*st = s->
streams
[0];
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if
(s->
pb
->
eof_reached
)
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return
AVERROR
(EIO);
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pkt->
dts
=
avio_tell
(s->
pb
) / (st->
codec
->
width
* (st->
codec
->
height
+ film->
leading
) * 4);
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pkt->
size
=
av_get_packet
(s->
pb
, pkt, st->
codec
->
width
* st->
codec
->
height
* 4);
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avio_skip
(s->
pb
, st->
codec
->
width
* film->
leading
* 4);
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if
(pkt->
size
< 0)
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return
pkt->
size
;
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pkt->
flags
|=
AV_PKT_FLAG_KEY
;
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return
0;
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}
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static
int
read_seek
(
AVFormatContext
*s,
int
stream_index, int64_t timestamp,
int
flags
)
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{
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AVStream
*st = s->
streams
[stream_index];
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avio_seek
(s->
pb
,
FFMAX
(timestamp, 0) * st->
codec
->
width
* st->
codec
->
height
* 4, SEEK_SET);
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return
0;
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}
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AVInputFormat
ff_filmstrip_demuxer
= {
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.
name
=
"filmstrip"
,
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.long_name =
NULL_IF_CONFIG_SMALL
(
"Adobe Filmstrip"
),
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.priv_data_size =
sizeof
(
FilmstripDemuxContext
),
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.
read_header
=
read_header
,
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.
read_packet
=
read_packet
,
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.
read_seek
=
read_seek
,
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.extensions =
"flm"
,
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};