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rl2.c
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1 /*
2  * RL2 Format Demuxer
3  * Copyright (c) 2008 Sascha Sommer (saschasommer@freenet.de)
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 /**
23  * RL2 file demuxer
24  * @file
25  * @author Sascha Sommer (saschasommer@freenet.de)
26  * @see http://wiki.multimedia.cx/index.php?title=RL2
27  *
28  * extradata:
29  * 2 byte le initial drawing offset within 320x200 viewport
30  * 4 byte le number of used colors
31  * 256 * 3 bytes rgb palette
32  * optional background_frame
33  */
34 
35 #include "libavutil/intreadwrite.h"
36 #include "libavutil/mathematics.h"
37 #include "avformat.h"
38 #include "internal.h"
39 
40 #define EXTRADATA1_SIZE (6 + 256 * 3) ///< video base, clr, palette
41 
42 #define FORM_TAG MKBETAG('F', 'O', 'R', 'M')
43 #define RLV2_TAG MKBETAG('R', 'L', 'V', '2')
44 #define RLV3_TAG MKBETAG('R', 'L', 'V', '3')
45 
46 typedef struct Rl2DemuxContext {
47  unsigned int index_pos[2]; ///< indexes in the sample tables
49 
50 
51 /**
52  * check if the file is in rl2 format
53  * @param p probe buffer
54  * @return 0 when the probe buffer does not contain rl2 data, > 0 otherwise
55  */
56 static int rl2_probe(AVProbeData *p)
57 {
58 
59  if(AV_RB32(&p->buf[0]) != FORM_TAG)
60  return 0;
61 
62  if(AV_RB32(&p->buf[8]) != RLV2_TAG &&
63  AV_RB32(&p->buf[8]) != RLV3_TAG)
64  return 0;
65 
66  return AVPROBE_SCORE_MAX;
67 }
68 
69 /**
70  * read rl2 header data and setup the avstreams
71  * @param s demuxer context
72  * @return 0 on success, AVERROR otherwise
73  */
75 {
76  AVIOContext *pb = s->pb;
77  AVStream *st;
78  unsigned int frame_count;
79  unsigned int audio_frame_counter = 0;
80  unsigned int video_frame_counter = 0;
81  unsigned int back_size;
82  unsigned short sound_rate;
83  unsigned short rate;
84  unsigned short channels;
85  unsigned short def_sound_size;
86  unsigned int signature;
87  unsigned int pts_den = 11025; /* video only case */
88  unsigned int pts_num = 1103;
89  unsigned int* chunk_offset = NULL;
90  int* chunk_size = NULL;
91  int* audio_size = NULL;
92  int i;
93  int ret = 0;
94 
95  avio_skip(pb,4); /* skip FORM tag */
96  back_size = avio_rl32(pb); /**< get size of the background frame */
97  signature = avio_rb32(pb);
98  avio_skip(pb, 4); /* data size */
99  frame_count = avio_rl32(pb);
100 
101  /* disallow back_sizes and frame_counts that may lead to overflows later */
102  if(back_size > INT_MAX/2 || frame_count > INT_MAX / sizeof(uint32_t))
103  return AVERROR_INVALIDDATA;
104 
105  avio_skip(pb, 2); /* encoding mentod */
106  sound_rate = avio_rl16(pb);
107  rate = avio_rl16(pb);
108  channels = avio_rl16(pb);
109  def_sound_size = avio_rl16(pb);
110 
111  /** setup video stream */
112  st = avformat_new_stream(s, NULL);
113  if(!st)
114  return AVERROR(ENOMEM);
115 
118  st->codec->codec_tag = 0; /* no fourcc */
119  st->codec->width = 320;
120  st->codec->height = 200;
121 
122  /** allocate and fill extradata */
124 
125  if(signature == RLV3_TAG && back_size > 0)
126  st->codec->extradata_size += back_size;
127 
130  if(!st->codec->extradata)
131  return AVERROR(ENOMEM);
132 
133  if(avio_read(pb,st->codec->extradata,st->codec->extradata_size) !=
134  st->codec->extradata_size)
135  return AVERROR(EIO);
136 
137  /** setup audio stream if present */
138  if(sound_rate){
139  if(channels <= 0)
140  return AVERROR_INVALIDDATA;
141 
142  pts_num = def_sound_size;
143  pts_den = rate;
144 
145  st = avformat_new_stream(s, NULL);
146  if (!st)
147  return AVERROR(ENOMEM);
150  st->codec->codec_tag = 1;
151  st->codec->channels = channels;
152  st->codec->bits_per_coded_sample = 8;
153  st->codec->sample_rate = rate;
154  st->codec->bit_rate = st->codec->channels * st->codec->sample_rate *
156  st->codec->block_align = st->codec->channels *
157  st->codec->bits_per_coded_sample / 8;
158  avpriv_set_pts_info(st,32,1,rate);
159  }
160 
161  avpriv_set_pts_info(s->streams[0], 32, pts_num, pts_den);
162 
163  chunk_size = av_malloc(frame_count * sizeof(uint32_t));
164  audio_size = av_malloc(frame_count * sizeof(uint32_t));
165  chunk_offset = av_malloc(frame_count * sizeof(uint32_t));
166 
167  if(!chunk_size || !audio_size || !chunk_offset){
168  av_free(chunk_size);
169  av_free(audio_size);
170  av_free(chunk_offset);
171  return AVERROR(ENOMEM);
172  }
173 
174  /** read offset and size tables */
175  for(i=0; i < frame_count;i++)
176  chunk_size[i] = avio_rl32(pb);
177  for(i=0; i < frame_count;i++)
178  chunk_offset[i] = avio_rl32(pb);
179  for(i=0; i < frame_count;i++)
180  audio_size[i] = avio_rl32(pb) & 0xFFFF;
181 
182  /** build the sample index */
183  for(i=0;i<frame_count;i++){
184  if(chunk_size[i] < 0 || audio_size[i] > chunk_size[i]){
185  ret = AVERROR_INVALIDDATA;
186  break;
187  }
188 
189  if(sound_rate && audio_size[i]){
190  av_add_index_entry(s->streams[1], chunk_offset[i],
191  audio_frame_counter,audio_size[i], 0, AVINDEX_KEYFRAME);
192  audio_frame_counter += audio_size[i] / channels;
193  }
194  av_add_index_entry(s->streams[0], chunk_offset[i] + audio_size[i],
195  video_frame_counter,chunk_size[i]-audio_size[i],0,AVINDEX_KEYFRAME);
196  ++video_frame_counter;
197  }
198 
199 
200  av_free(chunk_size);
201  av_free(audio_size);
202  av_free(chunk_offset);
203 
204  return ret;
205 }
206 
207 /**
208  * read a single audio or video packet
209  * @param s demuxer context
210  * @param pkt the packet to be filled
211  * @return 0 on success, AVERROR otherwise
212  */
214  AVPacket *pkt)
215 {
216  Rl2DemuxContext *rl2 = s->priv_data;
217  AVIOContext *pb = s->pb;
219  int i;
220  int ret = 0;
221  int stream_id = -1;
222  int64_t pos = INT64_MAX;
223 
224  /** check if there is a valid video or audio entry that can be used */
225  for(i=0; i<s->nb_streams; i++){
226  if(rl2->index_pos[i] < s->streams[i]->nb_index_entries
227  && s->streams[i]->index_entries[ rl2->index_pos[i] ].pos < pos){
228  sample = &s->streams[i]->index_entries[ rl2->index_pos[i] ];
229  pos= sample->pos;
230  stream_id= i;
231  }
232  }
233 
234  if(stream_id == -1)
235  return AVERROR_EOF;
236 
237  ++rl2->index_pos[stream_id];
238 
239  /** position the stream (will probably be there anyway) */
240  avio_seek(pb, sample->pos, SEEK_SET);
241 
242  /** fill the packet */
243  ret = av_get_packet(pb, pkt, sample->size);
244  if(ret != sample->size){
245  av_free_packet(pkt);
246  return AVERROR(EIO);
247  }
248 
249  pkt->stream_index = stream_id;
250  pkt->pts = sample->timestamp;
251 
252  return ret;
253 }
254 
255 /**
256  * seek to a new timestamp
257  * @param s demuxer context
258  * @param stream_index index of the stream that should be seeked
259  * @param timestamp wanted timestamp
260  * @param flags direction and seeking mode
261  * @return 0 on success, -1 otherwise
262  */
263 static int rl2_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
264 {
265  AVStream *st = s->streams[stream_index];
266  Rl2DemuxContext *rl2 = s->priv_data;
267  int i;
268  int index = av_index_search_timestamp(st, timestamp, flags);
269  if(index < 0)
270  return -1;
271 
272  rl2->index_pos[stream_index] = index;
273  timestamp = st->index_entries[index].timestamp;
274 
275  for(i=0; i < s->nb_streams; i++){
276  AVStream *st2 = s->streams[i];
277  index = av_index_search_timestamp(st2,
278  av_rescale_q(timestamp, st->time_base, st2->time_base),
279  flags | AVSEEK_FLAG_BACKWARD);
280 
281  if(index < 0)
282  index = 0;
283 
284  rl2->index_pos[i] = index;
285  }
286 
287  return 0;
288 }
289 
291  .name = "rl2",
292  .long_name = NULL_IF_CONFIG_SMALL("RL2"),
293  .priv_data_size = sizeof(Rl2DemuxContext),
298 };