swfdec.c
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1 /*
2  * Flash Compatible Streaming Format demuxer
3  * Copyright (c) 2000 Fabrice Bellard
4  * Copyright (c) 2003 Tinic Uro
5  *
6  * This file is part of Libav.
7  *
8  * Libav is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * Libav is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with Libav; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
23 #include "libavutil/intreadwrite.h"
24 #include "swf.h"
25 
26 static int get_swf_tag(AVIOContext *pb, int *len_ptr)
27 {
28  int tag, len;
29 
30  if (pb->eof_reached)
31  return -1;
32 
33  tag = avio_rl16(pb);
34  len = tag & 0x3f;
35  tag = tag >> 6;
36  if (len == 0x3f) {
37  len = avio_rl32(pb);
38  }
39 // av_log(NULL, AV_LOG_DEBUG, "Tag: %d - Len: %d\n", tag, len);
40  *len_ptr = len;
41  return tag;
42 }
43 
44 
45 static int swf_probe(AVProbeData *p)
46 {
47  /* check file header */
48  if ((p->buf[0] == 'F' || p->buf[0] == 'C') && p->buf[1] == 'W' &&
49  p->buf[2] == 'S')
50  return AVPROBE_SCORE_MAX;
51  else
52  return 0;
53 }
54 
56 {
57  SWFContext *swf = s->priv_data;
58  AVIOContext *pb = s->pb;
59  int nbits, len, tag;
60 
61  tag = avio_rb32(pb) & 0xffffff00;
62 
63  if (tag == MKBETAG('C', 'W', 'S', 0)) {
64  av_log(s, AV_LOG_ERROR, "Compressed SWF format not supported\n");
65  return AVERROR(EIO);
66  }
67  if (tag != MKBETAG('F', 'W', 'S', 0))
68  return AVERROR(EIO);
69  avio_rl32(pb);
70  /* skip rectangle size */
71  nbits = avio_r8(pb) >> 3;
72  len = (4 * nbits - 3 + 7) / 8;
73  avio_skip(pb, len);
74  swf->frame_rate = avio_rl16(pb); /* 8.8 fixed */
75  avio_rl16(pb); /* frame count */
76 
77  swf->samples_per_frame = 0;
79  return 0;
80 }
81 
83 {
84  SWFContext *swf = s->priv_data;
85  AVIOContext *pb = s->pb;
86  AVStream *vst = NULL, *ast = NULL, *st = 0;
87  int tag, len, i, frame, v, res;
88 
89  for(;;) {
90  uint64_t pos = avio_tell(pb);
91  tag = get_swf_tag(pb, &len);
92  if (tag < 0)
93  return AVERROR(EIO);
94  if (tag == TAG_VIDEOSTREAM) {
95  int ch_id = avio_rl16(pb);
96  len -= 2;
97 
98  for (i=0; i<s->nb_streams; i++) {
99  st = s->streams[i];
100  if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO && st->id == ch_id)
101  goto skip;
102  }
103 
104  avio_rl16(pb);
105  avio_rl16(pb);
106  avio_rl16(pb);
107  avio_r8(pb);
108  /* Check for FLV1 */
109  vst = avformat_new_stream(s, NULL);
110  if (!vst)
111  return -1;
112  vst->id = ch_id;
115  avpriv_set_pts_info(vst, 16, 256, swf->frame_rate);
116  vst->codec->time_base = (AVRational){ 256, swf->frame_rate };
117  len -= 8;
118  } else if (tag == TAG_STREAMHEAD || tag == TAG_STREAMHEAD2) {
119  /* streaming found */
120  int sample_rate_code;
121 
122  for (i=0; i<s->nb_streams; i++) {
123  st = s->streams[i];
124  if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO && st->id == -1)
125  goto skip;
126  }
127 
128  avio_r8(pb);
129  v = avio_r8(pb);
130  swf->samples_per_frame = avio_rl16(pb);
131  ast = avformat_new_stream(s, NULL);
132  if (!ast)
133  return -1;
134  ast->id = -1; /* -1 to avoid clash with video stream ch_id */
135  ast->codec->channels = 1 + (v&1);
136  ast->codec->codec_type = AVMEDIA_TYPE_AUDIO;
137  ast->codec->codec_id = ff_codec_get_id(swf_audio_codec_tags, (v>>4) & 15);
138  ast->need_parsing = AVSTREAM_PARSE_FULL;
139  sample_rate_code= (v>>2) & 3;
140  if (!sample_rate_code)
141  ast->codec->sample_rate = 5512;
142  else
143  ast->codec->sample_rate = 11025 << (sample_rate_code-1);
144  avpriv_set_pts_info(ast, 64, 1, ast->codec->sample_rate);
145  len -= 4;
146  } else if (tag == TAG_VIDEOFRAME) {
147  int ch_id = avio_rl16(pb);
148  len -= 2;
149  for(i=0; i<s->nb_streams; i++) {
150  st = s->streams[i];
151  if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO && st->id == ch_id) {
152  frame = avio_rl16(pb);
153  if ((res = av_get_packet(pb, pkt, len-2)) < 0)
154  return res;
155  pkt->pos = pos;
156  pkt->pts = frame;
157  pkt->stream_index = st->index;
158  return pkt->size;
159  }
160  }
161  } else if (tag == TAG_STREAMBLOCK) {
162  for (i = 0; i < s->nb_streams; i++) {
163  st = s->streams[i];
164  if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO && st->id == -1) {
165  if (st->codec->codec_id == CODEC_ID_MP3) {
166  avio_skip(pb, 4);
167  if ((res = av_get_packet(pb, pkt, len-4)) < 0)
168  return res;
169  } else { // ADPCM, PCM
170  if ((res = av_get_packet(pb, pkt, len)) < 0)
171  return res;
172  }
173  pkt->pos = pos;
174  pkt->stream_index = st->index;
175  return pkt->size;
176  }
177  }
178  } else if (tag == TAG_JPEG2) {
179  for (i=0; i<s->nb_streams; i++) {
180  st = s->streams[i];
181  if (st->codec->codec_id == CODEC_ID_MJPEG && st->id == -2)
182  break;
183  }
184  if (i == s->nb_streams) {
185  vst = avformat_new_stream(s, NULL);
186  if (!vst)
187  return -1;
188  vst->id = -2; /* -2 to avoid clash with video stream and audio stream */
190  vst->codec->codec_id = CODEC_ID_MJPEG;
191  avpriv_set_pts_info(vst, 64, 256, swf->frame_rate);
192  vst->codec->time_base = (AVRational){ 256, swf->frame_rate };
193  st = vst;
194  }
195  avio_rl16(pb); /* BITMAP_ID */
196  if ((res = av_new_packet(pkt, len-2)) < 0)
197  return res;
198  avio_read(pb, pkt->data, 4);
199  if (AV_RB32(pkt->data) == 0xffd8ffd9 ||
200  AV_RB32(pkt->data) == 0xffd9ffd8) {
201  /* old SWF files containing SOI/EOI as data start */
202  /* files created by swink have reversed tag */
203  pkt->size -= 4;
204  avio_read(pb, pkt->data, pkt->size);
205  } else {
206  avio_read(pb, pkt->data + 4, pkt->size - 4);
207  }
208  pkt->pos = pos;
209  pkt->stream_index = st->index;
210  return pkt->size;
211  }
212  skip:
213  avio_skip(pb, len);
214  }
215 }
216 
218  .name = "swf",
219  .long_name = NULL_IF_CONFIG_SMALL("Flash format"),
220  .priv_data_size = sizeof(SWFContext),
224 };