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ffmpeg/libavformat/swfdec.c

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/*
* Flash Compatible Streaming Format demuxer
* Copyright (c) 2000 Fabrice Bellard
* Copyright (c) 2003 Tinic Uro
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/intreadwrite.h"
#include "swf.h"
static int get_swf_tag(AVIOContext *pb, int *len_ptr)
{
int tag, len;
if (url_feof(pb))
return -1;
tag = avio_rl16(pb);
len = tag & 0x3f;
tag = tag >> 6;
if (len == 0x3f) {
len = avio_rl32(pb);
}
// av_log(NULL, AV_LOG_DEBUG, "Tag: %d - Len: %d\n", tag, len);
*len_ptr = len;
return tag;
}
static int swf_probe(AVProbeData *p)
{
/* check file header */
if ((p->buf[0] == 'F' || p->buf[0] == 'C') && p->buf[1] == 'W' &&
p->buf[2] == 'S')
return AVPROBE_SCORE_MAX;
else
return 0;
}
static int swf_read_header(AVFormatContext *s, AVFormatParameters *ap)
{
SWFContext *swf = s->priv_data;
AVIOContext *pb = s->pb;
int nbits, len, tag;
tag = avio_rb32(pb) & 0xffffff00;
if (tag == MKBETAG('C', 'W', 'S', 0)) {
av_log(s, AV_LOG_ERROR, "Compressed SWF format not supported\n");
return AVERROR(EIO);
}
if (tag != MKBETAG('F', 'W', 'S', 0))
return AVERROR(EIO);
avio_rl32(pb);
/* skip rectangle size */
nbits = avio_r8(pb) >> 3;
len = (4 * nbits - 3 + 7) / 8;
avio_skip(pb, len);
swf->frame_rate = avio_rl16(pb); /* 8.8 fixed */
avio_rl16(pb); /* frame count */
swf->samples_per_frame = 0;
s->ctx_flags |= AVFMTCTX_NOHEADER;
return 0;
}
static int swf_read_packet(AVFormatContext *s, AVPacket *pkt)
{
SWFContext *swf = s->priv_data;
AVIOContext *pb = s->pb;
AVStream *vst = NULL, *ast = NULL, *st = 0;
int tag, len, i, frame, v;
for(;;) {
uint64_t pos = avio_tell(pb);
tag = get_swf_tag(pb, &len);
if (tag < 0)
return AVERROR(EIO);
if (tag == TAG_VIDEOSTREAM) {
int ch_id = avio_rl16(pb);
len -= 2;
for (i=0; i<s->nb_streams; i++) {
st = s->streams[i];
if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO && st->id == ch_id)
goto skip;
}
avio_rl16(pb);
avio_rl16(pb);
avio_rl16(pb);
avio_r8(pb);
/* Check for FLV1 */
vst = av_new_stream(s, ch_id);
if (!vst)
return -1;
vst->codec->codec_type = AVMEDIA_TYPE_VIDEO;
vst->codec->codec_id = ff_codec_get_id(swf_codec_tags, avio_r8(pb));
av_set_pts_info(vst, 16, 256, swf->frame_rate);
vst->codec->time_base = (AVRational){ 256, swf->frame_rate };
len -= 8;
} else if (tag == TAG_STREAMHEAD || tag == TAG_STREAMHEAD2) {
/* streaming found */
int sample_rate_code;
for (i=0; i<s->nb_streams; i++) {
st = s->streams[i];
if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO && st->id == -1)
goto skip;
}
avio_r8(pb);
v = avio_r8(pb);
swf->samples_per_frame = avio_rl16(pb);
ast = av_new_stream(s, -1); /* -1 to avoid clash with video stream ch_id */
if (!ast)
return -1;
ast->codec->channels = 1 + (v&1);
ast->codec->codec_type = AVMEDIA_TYPE_AUDIO;
ast->codec->codec_id = ff_codec_get_id(swf_audio_codec_tags, (v>>4) & 15);
ast->need_parsing = AVSTREAM_PARSE_FULL;
sample_rate_code= (v>>2) & 3;
if (!sample_rate_code)
ast->codec->sample_rate = 5512;
else
ast->codec->sample_rate = 11025 << (sample_rate_code-1);
av_set_pts_info(ast, 64, 1, ast->codec->sample_rate);
len -= 4;
} else if (tag == TAG_VIDEOFRAME) {
int ch_id = avio_rl16(pb);
len -= 2;
for(i=0; i<s->nb_streams; i++) {
st = s->streams[i];
if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO && st->id == ch_id) {
frame = avio_rl16(pb);
av_get_packet(pb, pkt, len-2);
pkt->pos = pos;
pkt->pts = frame;
pkt->stream_index = st->index;
return pkt->size;
}
}
} else if (tag == TAG_STREAMBLOCK) {
for (i = 0; i < s->nb_streams; i++) {
st = s->streams[i];
if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO && st->id == -1) {
if (st->codec->codec_id == CODEC_ID_MP3) {
avio_skip(pb, 4);
av_get_packet(pb, pkt, len-4);
} else { // ADPCM, PCM
av_get_packet(pb, pkt, len);
}
pkt->pos = pos;
pkt->stream_index = st->index;
return pkt->size;
}
}
} else if (tag == TAG_JPEG2) {
for (i=0; i<s->nb_streams; i++) {
st = s->streams[i];
if (st->codec->codec_id == CODEC_ID_MJPEG && st->id == -2)
break;
}
if (i == s->nb_streams) {
vst = av_new_stream(s, -2); /* -2 to avoid clash with video stream and audio stream */
if (!vst)
return -1;
vst->codec->codec_type = AVMEDIA_TYPE_VIDEO;
vst->codec->codec_id = CODEC_ID_MJPEG;
av_set_pts_info(vst, 64, 256, swf->frame_rate);
vst->codec->time_base = (AVRational){ 256, swf->frame_rate };
st = vst;
}
avio_rl16(pb); /* BITMAP_ID */
av_new_packet(pkt, len-2);
avio_read(pb, pkt->data, 4);
if (AV_RB32(pkt->data) == 0xffd8ffd9 ||
AV_RB32(pkt->data) == 0xffd9ffd8) {
/* old SWF files containing SOI/EOI as data start */
/* files created by swink have reversed tag */
pkt->size -= 4;
avio_read(pb, pkt->data, pkt->size);
} else {
avio_read(pb, pkt->data + 4, pkt->size - 4);
}
pkt->pos = pos;
pkt->stream_index = st->index;
return pkt->size;
}
skip:
avio_skip(pb, len);
}
}
AVInputFormat ff_swf_demuxer = {
.name = "swf",
.long_name = NULL_IF_CONFIG_SMALL("Flash format"),
.priv_data_size = sizeof(SWFContext),
.read_probe = swf_probe,
.read_header = swf_read_header,
.read_packet = swf_read_packet,
};
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