rmenc.c
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1 /*
2  * "Real" compatible muxer.
3  * Copyright (c) 2000, 2001 Fabrice Bellard
4  *
5  * This file is part of Libav.
6  *
7  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 #include "avformat.h"
22 #include "avio_internal.h"
23 #include "rm.h"
24 #include "libavutil/dict.h"
25 
26 typedef struct {
30  /* codec related output */
31  int bit_rate;
32  float frame_rate;
33  int nb_frames; /* current frame number */
34  int total_frames; /* total number of frames */
35  int num;
37 } StreamInfo;
38 
39 typedef struct {
40  StreamInfo streams[2];
41  StreamInfo *audio_stream, *video_stream;
42  int data_pos; /* position of the data after the header */
43 } RMMuxContext;
44 
45 /* in ms */
46 #define BUFFER_DURATION 0
47 /* the header needs at most 7 + 4 + 12 B */
48 #define MAX_HEADER_SIZE (7 + 4 + 12)
49 /* UINT16_MAX is the maximal chunk size */
50 #define MAX_PACKET_SIZE (UINT16_MAX - MAX_HEADER_SIZE)
51 
52 
53 static void put_str(AVIOContext *s, const char *tag)
54 {
55  avio_wb16(s,strlen(tag));
56  while (*tag) {
57  avio_w8(s, *tag++);
58  }
59 }
60 
61 static void put_str8(AVIOContext *s, const char *tag)
62 {
63  avio_w8(s, strlen(tag));
64  while (*tag) {
65  avio_w8(s, *tag++);
66  }
67 }
68 
70  int data_size, int index_pos)
71 {
72  RMMuxContext *rm = ctx->priv_data;
73  AVIOContext *s = ctx->pb;
74  StreamInfo *stream;
75  unsigned char *data_offset_ptr, *start_ptr;
76  const char *desc, *mimetype;
77  int nb_packets, packet_total_size, packet_max_size, size, packet_avg_size, i;
78  int bit_rate, v, duration, flags, data_pos;
80 
81  start_ptr = s->buf_ptr;
82 
83  ffio_wfourcc(s, ".RMF");
84  avio_wb32(s,18); /* header size */
85  avio_wb16(s,0);
86  avio_wb32(s,0);
87  avio_wb32(s,4 + ctx->nb_streams); /* num headers */
88 
89  ffio_wfourcc(s,"PROP");
90  avio_wb32(s, 50);
91  avio_wb16(s, 0);
92  packet_max_size = 0;
93  packet_total_size = 0;
94  nb_packets = 0;
95  bit_rate = 0;
96  duration = 0;
97  for(i=0;i<ctx->nb_streams;i++) {
98  StreamInfo *stream = &rm->streams[i];
99  bit_rate += stream->bit_rate;
100  if (stream->packet_max_size > packet_max_size)
101  packet_max_size = stream->packet_max_size;
102  nb_packets += stream->nb_packets;
103  packet_total_size += stream->packet_total_size;
104  /* select maximum duration */
105  v = (int) (1000.0 * (float)stream->total_frames / stream->frame_rate);
106  if (v > duration)
107  duration = v;
108  }
109  avio_wb32(s, bit_rate); /* max bit rate */
110  avio_wb32(s, bit_rate); /* avg bit rate */
111  avio_wb32(s, packet_max_size); /* max packet size */
112  if (nb_packets > 0)
113  packet_avg_size = packet_total_size / nb_packets;
114  else
115  packet_avg_size = 0;
116  avio_wb32(s, packet_avg_size); /* avg packet size */
117  avio_wb32(s, nb_packets); /* num packets */
118  avio_wb32(s, duration); /* duration */
119  avio_wb32(s, BUFFER_DURATION); /* preroll */
120  avio_wb32(s, index_pos); /* index offset */
121  /* computation of data the data offset */
122  data_offset_ptr = s->buf_ptr;
123  avio_wb32(s, 0); /* data offset : will be patched after */
124  avio_wb16(s, ctx->nb_streams); /* num streams */
125  flags = 1 | 2; /* save allowed & perfect play */
126  if (!s->seekable)
127  flags |= 4; /* live broadcast */
128  avio_wb16(s, flags);
129 
130  /* comments */
131 
132  ffio_wfourcc(s,"CONT");
133  size = 4 * 2 + 10;
134  for(i=0; i<FF_ARRAY_ELEMS(ff_rm_metadata); i++) {
135  tag = av_dict_get(ctx->metadata, ff_rm_metadata[i], NULL, 0);
136  if(tag) size += strlen(tag->value);
137  }
138  avio_wb32(s,size);
139  avio_wb16(s,0);
140  for(i=0; i<FF_ARRAY_ELEMS(ff_rm_metadata); i++) {
141  tag = av_dict_get(ctx->metadata, ff_rm_metadata[i], NULL, 0);
142  put_str(s, tag ? tag->value : "");
143  }
144 
145  for(i=0;i<ctx->nb_streams;i++) {
146  int codec_data_size;
147 
148  stream = &rm->streams[i];
149 
150  if (stream->enc->codec_type == AVMEDIA_TYPE_AUDIO) {
151  desc = "The Audio Stream";
152  mimetype = "audio/x-pn-realaudio";
153  codec_data_size = 73;
154  } else {
155  desc = "The Video Stream";
156  mimetype = "video/x-pn-realvideo";
157  codec_data_size = 34;
158  }
159 
160  ffio_wfourcc(s,"MDPR");
161  size = 10 + 9 * 4 + strlen(desc) + strlen(mimetype) + codec_data_size;
162  avio_wb32(s, size);
163  avio_wb16(s, 0);
164 
165  avio_wb16(s, i); /* stream number */
166  avio_wb32(s, stream->bit_rate); /* max bit rate */
167  avio_wb32(s, stream->bit_rate); /* avg bit rate */
168  avio_wb32(s, stream->packet_max_size); /* max packet size */
169  if (stream->nb_packets > 0)
170  packet_avg_size = stream->packet_total_size /
171  stream->nb_packets;
172  else
173  packet_avg_size = 0;
174  avio_wb32(s, packet_avg_size); /* avg packet size */
175  avio_wb32(s, 0); /* start time */
176  avio_wb32(s, BUFFER_DURATION); /* preroll */
177  /* duration */
178  if (!s->seekable || !stream->total_frames)
179  avio_wb32(s, (int)(3600 * 1000));
180  else
181  avio_wb32(s, (int)(stream->total_frames * 1000 / stream->frame_rate));
182  put_str8(s, desc);
183  put_str8(s, mimetype);
184  avio_wb32(s, codec_data_size);
185 
186  if (stream->enc->codec_type == AVMEDIA_TYPE_AUDIO) {
187  int coded_frame_size, fscode, sample_rate;
188  sample_rate = stream->enc->sample_rate;
189  coded_frame_size = (stream->enc->bit_rate *
190  stream->enc->frame_size) / (8 * sample_rate);
191  /* audio codec info */
192  avio_write(s, ".ra", 3);
193  avio_w8(s, 0xfd);
194  avio_wb32(s, 0x00040000); /* version */
195  ffio_wfourcc(s, ".ra4");
196  avio_wb32(s, 0x01b53530); /* stream length */
197  avio_wb16(s, 4); /* unknown */
198  avio_wb32(s, 0x39); /* header size */
199 
200  switch(sample_rate) {
201  case 48000:
202  case 24000:
203  case 12000:
204  fscode = 1;
205  break;
206  default:
207  case 44100:
208  case 22050:
209  case 11025:
210  fscode = 2;
211  break;
212  case 32000:
213  case 16000:
214  case 8000:
215  fscode = 3;
216  }
217  avio_wb16(s, fscode); /* codec additional info, for AC-3, seems
218  to be a frequency code */
219  /* special hack to compensate rounding errors... */
220  if (coded_frame_size == 557)
221  coded_frame_size--;
222  avio_wb32(s, coded_frame_size); /* frame length */
223  avio_wb32(s, 0x51540); /* unknown */
224  avio_wb32(s, 0x249f0); /* unknown */
225  avio_wb32(s, 0x249f0); /* unknown */
226  avio_wb16(s, 0x01);
227  /* frame length : seems to be very important */
228  avio_wb16(s, coded_frame_size);
229  avio_wb32(s, 0); /* unknown */
230  avio_wb16(s, stream->enc->sample_rate); /* sample rate */
231  avio_wb32(s, 0x10); /* unknown */
232  avio_wb16(s, stream->enc->channels);
233  put_str8(s, "Int0"); /* codec name */
234  if (stream->enc->codec_tag) {
235  avio_w8(s, 4); /* tag length */
236  avio_wl32(s, stream->enc->codec_tag);
237  } else {
238  av_log(ctx, AV_LOG_ERROR, "Invalid codec tag\n");
239  return -1;
240  }
241  avio_wb16(s, 0); /* title length */
242  avio_wb16(s, 0); /* author length */
243  avio_wb16(s, 0); /* copyright length */
244  avio_w8(s, 0); /* end of header */
245  } else {
246  /* video codec info */
247  avio_wb32(s,34); /* size */
248  ffio_wfourcc(s, "VIDO");
249  if(stream->enc->codec_id == CODEC_ID_RV10)
250  ffio_wfourcc(s,"RV10");
251  else
252  ffio_wfourcc(s,"RV20");
253  avio_wb16(s, stream->enc->width);
254  avio_wb16(s, stream->enc->height);
255  avio_wb16(s, (int) stream->frame_rate); /* frames per seconds ? */
256  avio_wb32(s,0); /* unknown meaning */
257  avio_wb16(s, (int) stream->frame_rate); /* unknown meaning */
258  avio_wb32(s,0); /* unknown meaning */
259  avio_wb16(s, 8); /* unknown meaning */
260  /* Seems to be the codec version: only use basic H263. The next
261  versions seems to add a diffential DC coding as in
262  MPEG... nothing new under the sun */
263  if(stream->enc->codec_id == CODEC_ID_RV10)
264  avio_wb32(s,0x10000000);
265  else
266  avio_wb32(s,0x20103001);
267  //avio_wb32(s,0x10003000);
268  }
269  }
270 
271  /* patch data offset field */
272  data_pos = s->buf_ptr - start_ptr;
273  rm->data_pos = data_pos;
274  data_offset_ptr[0] = data_pos >> 24;
275  data_offset_ptr[1] = data_pos >> 16;
276  data_offset_ptr[2] = data_pos >> 8;
277  data_offset_ptr[3] = data_pos;
278 
279  /* data stream */
280  ffio_wfourcc(s, "DATA");
281  avio_wb32(s,data_size + 10 + 8);
282  avio_wb16(s,0);
283 
284  avio_wb32(s, nb_packets); /* number of packets */
285  avio_wb32(s,0); /* next data header */
286  return 0;
287 }
288 
290  int length, int key_frame)
291 {
292  int timestamp;
293  AVIOContext *s = ctx->pb;
294 
295  stream->nb_packets++;
296  stream->packet_total_size += length;
297  if (length > stream->packet_max_size)
298  stream->packet_max_size = length;
299 
300  avio_wb16(s,0); /* version */
301  avio_wb16(s,length + 12);
302  avio_wb16(s, stream->num); /* stream number */
303  timestamp = (1000 * (float)stream->nb_frames) / stream->frame_rate;
304  avio_wb32(s, timestamp); /* timestamp */
305  avio_w8(s, 0); /* reserved */
306  avio_w8(s, key_frame ? 2 : 0); /* flags */
307 }
308 
310 {
311  RMMuxContext *rm = s->priv_data;
312  StreamInfo *stream;
313  int n;
314  AVCodecContext *codec;
315 
316  for(n=0;n<s->nb_streams;n++) {
317  s->streams[n]->id = n;
318  codec = s->streams[n]->codec;
319  stream = &rm->streams[n];
320  memset(stream, 0, sizeof(StreamInfo));
321  stream->num = n;
322  stream->bit_rate = codec->bit_rate;
323  stream->enc = codec;
324 
325  switch(codec->codec_type) {
326  case AVMEDIA_TYPE_AUDIO:
327  rm->audio_stream = stream;
328  stream->frame_rate = (float)codec->sample_rate / (float)codec->frame_size;
329  /* XXX: dummy values */
330  stream->packet_max_size = 1024;
331  stream->nb_packets = 0;
332  stream->total_frames = stream->nb_packets;
333  break;
334  case AVMEDIA_TYPE_VIDEO:
335  rm->video_stream = stream;
336  stream->frame_rate = (float)codec->time_base.den / (float)codec->time_base.num;
337  /* XXX: dummy values */
338  stream->packet_max_size = 4096;
339  stream->nb_packets = 0;
340  stream->total_frames = stream->nb_packets;
341  break;
342  default:
343  return -1;
344  }
345  }
346 
347  if (rv10_write_header(s, 0, 0))
348  return AVERROR_INVALIDDATA;
349  avio_flush(s->pb);
350  return 0;
351 }
352 
353 static int rm_write_audio(AVFormatContext *s, const uint8_t *buf, int size, int flags)
354 {
355  uint8_t *buf1;
356  RMMuxContext *rm = s->priv_data;
357  AVIOContext *pb = s->pb;
358  StreamInfo *stream = rm->audio_stream;
359  int i;
360 
361  /* XXX: suppress this malloc */
362  buf1 = av_malloc(size * sizeof(uint8_t));
363 
364  write_packet_header(s, stream, size, !!(flags & AV_PKT_FLAG_KEY));
365 
366  if (stream->enc->codec_id == CODEC_ID_AC3) {
367  /* for AC-3, the words seem to be reversed */
368  for(i=0;i<size;i+=2) {
369  buf1[i] = buf[i+1];
370  buf1[i+1] = buf[i];
371  }
372  avio_write(pb, buf1, size);
373  } else {
374  avio_write(pb, buf, size);
375  }
376  avio_flush(pb);
377  stream->nb_frames++;
378  av_free(buf1);
379  return 0;
380 }
381 
382 static int rm_write_video(AVFormatContext *s, const uint8_t *buf, int size, int flags)
383 {
384  RMMuxContext *rm = s->priv_data;
385  AVIOContext *pb = s->pb;
386  StreamInfo *stream = rm->video_stream;
387  int key_frame = !!(flags & AV_PKT_FLAG_KEY);
388 
389  /* XXX: this is incorrect: should be a parameter */
390 
391  /* Well, I spent some time finding the meaning of these bits. I am
392  not sure I understood everything, but it works !! */
393 #if 1
394  if (size > MAX_PACKET_SIZE) {
395  av_log_missing_feature(s, "Muxing packets larger than 64 kB", 0);
396  return AVERROR(ENOSYS);
397  }
398  write_packet_header(s, stream, size + 7 + (size >= 0x4000)*4, key_frame);
399  /* bit 7: '1' if final packet of a frame converted in several packets */
400  avio_w8(pb, 0x81);
401  /* bit 7: '1' if I frame. bits 6..0 : sequence number in current
402  frame starting from 1 */
403  if (key_frame) {
404  avio_w8(pb, 0x81);
405  } else {
406  avio_w8(pb, 0x01);
407  }
408  if(size >= 0x4000){
409  avio_wb32(pb, size); /* total frame size */
410  avio_wb32(pb, size); /* offset from the start or the end */
411  }else{
412  avio_wb16(pb, 0x4000 | size); /* total frame size */
413  avio_wb16(pb, 0x4000 | size); /* offset from the start or the end */
414  }
415 #else
416  /* full frame */
417  write_packet_header(s, size + 6);
418  avio_w8(pb, 0xc0);
419  avio_wb16(pb, 0x4000 + size); /* total frame size */
420  avio_wb16(pb, 0x4000 + packet_number * 126); /* position in stream */
421 #endif
422  avio_w8(pb, stream->nb_frames & 0xff);
423 
424  avio_write(pb, buf, size);
425  avio_flush(pb);
426 
427  stream->nb_frames++;
428  return 0;
429 }
430 
432 {
433  if (s->streams[pkt->stream_index]->codec->codec_type ==
435  return rm_write_audio(s, pkt->data, pkt->size, pkt->flags);
436  else
437  return rm_write_video(s, pkt->data, pkt->size, pkt->flags);
438 }
439 
441 {
442  RMMuxContext *rm = s->priv_data;
443  int data_size, index_pos, i;
444  AVIOContext *pb = s->pb;
445 
446  if (s->pb->seekable) {
447  /* end of file: finish to write header */
448  index_pos = avio_tell(pb);
449  data_size = index_pos - rm->data_pos;
450 
451  /* FIXME: write index */
452 
453  /* undocumented end header */
454  avio_wb32(pb, 0);
455  avio_wb32(pb, 0);
456 
457  avio_seek(pb, 0, SEEK_SET);
458  for(i=0;i<s->nb_streams;i++)
459  rm->streams[i].total_frames = rm->streams[i].nb_frames;
460  rv10_write_header(s, data_size, 0);
461  } else {
462  /* undocumented end header */
463  avio_wb32(pb, 0);
464  avio_wb32(pb, 0);
465  }
466  avio_flush(pb);
467  return 0;
468 }
469 
470 
472  .name = "rm",
473  .long_name = NULL_IF_CONFIG_SMALL("RealMedia format"),
474  .mime_type = "application/vnd.rn-realmedia",
475  .extensions = "rm,ra",
476  .priv_data_size = sizeof(RMMuxContext),
477  .audio_codec = CODEC_ID_AC3,
478  .video_codec = CODEC_ID_RV10,
482  .codec_tag= (const AVCodecTag* const []){ff_rm_codec_tags, 0},
483 };