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 (len < 0) {
95  av_log(s, AV_LOG_ERROR, "invalid tag length: %d\n", len);
96  return AVERROR_INVALIDDATA;
97  }
98  if (tag == TAG_VIDEOSTREAM) {
99  int ch_id = avio_rl16(pb);
100  len -= 2;
101 
102  for (i=0; i<s->nb_streams; i++) {
103  st = s->streams[i];
104  if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO && st->id == ch_id)
105  goto skip;
106  }
107 
108  avio_rl16(pb);
109  avio_rl16(pb);
110  avio_rl16(pb);
111  avio_r8(pb);
112  /* Check for FLV1 */
113  vst = avformat_new_stream(s, NULL);
114  if (!vst)
115  return -1;
116  vst->id = ch_id;
119  avpriv_set_pts_info(vst, 16, 256, swf->frame_rate);
120  vst->codec->time_base = (AVRational){ 256, swf->frame_rate };
121  len -= 8;
122  } else if (tag == TAG_STREAMHEAD || tag == TAG_STREAMHEAD2) {
123  /* streaming found */
124  int sample_rate_code;
125 
126  for (i=0; i<s->nb_streams; i++) {
127  st = s->streams[i];
128  if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO && st->id == -1)
129  goto skip;
130  }
131 
132  avio_r8(pb);
133  v = avio_r8(pb);
134  swf->samples_per_frame = avio_rl16(pb);
135  ast = avformat_new_stream(s, NULL);
136  if (!ast)
137  return -1;
138  ast->id = -1; /* -1 to avoid clash with video stream ch_id */
139  ast->codec->channels = 1 + (v&1);
140  ast->codec->codec_type = AVMEDIA_TYPE_AUDIO;
141  ast->codec->codec_id = ff_codec_get_id(swf_audio_codec_tags, (v>>4) & 15);
142  ast->need_parsing = AVSTREAM_PARSE_FULL;
143  sample_rate_code= (v>>2) & 3;
144  if (!sample_rate_code)
145  ast->codec->sample_rate = 5512;
146  else
147  ast->codec->sample_rate = 11025 << (sample_rate_code-1);
148  avpriv_set_pts_info(ast, 64, 1, ast->codec->sample_rate);
149  len -= 4;
150  } else if (tag == TAG_VIDEOFRAME) {
151  int ch_id = avio_rl16(pb);
152  len -= 2;
153  for(i=0; i<s->nb_streams; i++) {
154  st = s->streams[i];
155  if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO && st->id == ch_id) {
156  frame = avio_rl16(pb);
157  len -= 2;
158  if (len <= 0)
159  goto skip;
160  if ((res = av_get_packet(pb, pkt, len)) < 0)
161  return res;
162  pkt->pos = pos;
163  pkt->pts = frame;
164  pkt->stream_index = st->index;
165  return pkt->size;
166  }
167  }
168  } else if (tag == TAG_STREAMBLOCK) {
169  for (i = 0; i < s->nb_streams; i++) {
170  st = s->streams[i];
171  if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO && st->id == -1) {
172  if (st->codec->codec_id == CODEC_ID_MP3) {
173  avio_skip(pb, 4);
174  len -= 4;
175  if (len <= 0)
176  goto skip;
177  if ((res = av_get_packet(pb, pkt, len)) < 0)
178  return res;
179  } else { // ADPCM, PCM
180  if (len <= 0)
181  goto skip;
182  if ((res = av_get_packet(pb, pkt, len)) < 0)
183  return res;
184  }
185  pkt->pos = pos;
186  pkt->stream_index = st->index;
187  return pkt->size;
188  }
189  }
190  } else if (tag == TAG_JPEG2) {
191  for (i=0; i<s->nb_streams; i++) {
192  st = s->streams[i];
193  if (st->codec->codec_id == CODEC_ID_MJPEG && st->id == -2)
194  break;
195  }
196  if (i == s->nb_streams) {
197  vst = avformat_new_stream(s, NULL);
198  if (!vst)
199  return -1;
200  vst->id = -2; /* -2 to avoid clash with video stream and audio stream */
202  vst->codec->codec_id = CODEC_ID_MJPEG;
203  avpriv_set_pts_info(vst, 64, 256, swf->frame_rate);
204  vst->codec->time_base = (AVRational){ 256, swf->frame_rate };
205  st = vst;
206  }
207  avio_rl16(pb); /* BITMAP_ID */
208  len -= 2;
209  if (len < 4)
210  goto skip;
211  if ((res = av_new_packet(pkt, len)) < 0)
212  return res;
213  avio_read(pb, pkt->data, 4);
214  if (AV_RB32(pkt->data) == 0xffd8ffd9 ||
215  AV_RB32(pkt->data) == 0xffd9ffd8) {
216  /* old SWF files containing SOI/EOI as data start */
217  /* files created by swink have reversed tag */
218  pkt->size -= 4;
219  avio_read(pb, pkt->data, pkt->size);
220  } else {
221  avio_read(pb, pkt->data + 4, pkt->size - 4);
222  }
223  pkt->pos = pos;
224  pkt->stream_index = st->index;
225  return pkt->size;
226  }
227  skip:
228  len = FFMAX(0, len);
229  avio_skip(pb, len);
230  }
231 }
232 
234  .name = "swf",
235  .long_name = NULL_IF_CONFIG_SMALL("Flash format"),
236  .priv_data_size = sizeof(SWFContext),
240 };