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rtpdec_jpeg.c
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1 /*
2  * RTP JPEG-compressed Video Depacketizer, RFC 2435
3  * Copyright (c) 2012 Samuel Pitoiset
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 #include "avformat.h"
23 #include "rtpdec.h"
24 #include "rtpdec_formats.h"
25 #include "libavutil/intreadwrite.h"
26 #include "libavcodec/mjpeg.h"
27 #include "libavcodec/bytestream.h"
28 
29 /**
30  * RTP/JPEG specific private data.
31  */
32 struct PayloadContext {
33  AVIOContext *frame; ///< current frame buffer
34  uint32_t timestamp; ///< current frame timestamp
35  int hdr_size; ///< size of the current frame header
36  uint8_t qtables[128][128];
38 };
39 
40 static const uint8_t default_quantizers[128] = {
41  /* luma table */
42  16, 11, 12, 14, 12, 10, 16, 14,
43  13, 14, 18, 17, 16, 19, 24, 40,
44  26, 24, 22, 22, 24, 49, 35, 37,
45  29, 40, 58, 51, 61, 60, 57, 51,
46  56, 55, 64, 72, 92, 78, 64, 68,
47  87, 69, 55, 56, 80, 109, 81, 87,
48  95, 98, 103, 104, 103, 62, 77, 113,
49  121, 112, 100, 120, 92, 101, 103, 99,
50 
51  /* chroma table */
52  17, 18, 18, 24, 21, 24, 47, 26,
53  26, 47, 99, 66, 56, 66, 99, 99,
54  99, 99, 99, 99, 99, 99, 99, 99,
55  99, 99, 99, 99, 99, 99, 99, 99,
56  99, 99, 99, 99, 99, 99, 99, 99,
57  99, 99, 99, 99, 99, 99, 99, 99,
58  99, 99, 99, 99, 99, 99, 99, 99,
59  99, 99, 99, 99, 99, 99, 99, 99
60 };
61 
63 {
64  return av_mallocz(sizeof(PayloadContext));
65 }
66 
67 static inline void free_frame_if_needed(PayloadContext *jpeg)
68 {
69  if (jpeg->frame) {
70  uint8_t *p;
71  avio_close_dyn_buf(jpeg->frame, &p);
72  av_free(p);
73  jpeg->frame = NULL;
74  }
75 }
76 
78 {
80  av_free(jpeg);
81 }
82 
83 static int jpeg_create_huffman_table(PutByteContext *p, int table_class,
84  int table_id, const uint8_t *bits_table,
85  const uint8_t *value_table)
86 {
87  int i, n = 0;
88 
89  bytestream2_put_byte(p, table_class << 4 | table_id);
90 
91  for (i = 1; i <= 16; i++) {
92  n += bits_table[i];
93  bytestream2_put_byte(p, bits_table[i]);
94  }
95 
96  for (i = 0; i < n; i++) {
97  bytestream2_put_byte(p, value_table[i]);
98  }
99  return n + 17;
100 }
101 
102 static void jpeg_put_marker(PutByteContext *pbc, int code)
103 {
104  bytestream2_put_byte(pbc, 0xff);
105  bytestream2_put_byte(pbc, code);
106 }
107 
108 static int jpeg_create_header(uint8_t *buf, int size, uint32_t type, uint32_t w,
109  uint32_t h, const uint8_t *qtable, int nb_qtable)
110 {
111  PutByteContext pbc;
112  uint8_t *dht_size_ptr;
113  int dht_size, i;
114 
115  bytestream2_init_writer(&pbc, buf, size);
116 
117  /* Convert from blocks to pixels. */
118  w <<= 3;
119  h <<= 3;
120 
121  /* SOI */
122  jpeg_put_marker(&pbc, SOI);
123 
124  /* JFIF header */
125  jpeg_put_marker(&pbc, APP0);
126  bytestream2_put_be16(&pbc, 16);
127  bytestream2_put_buffer(&pbc, "JFIF", 5);
128  bytestream2_put_be16(&pbc, 0x0201);
129  bytestream2_put_byte(&pbc, 0);
130  bytestream2_put_be16(&pbc, 1);
131  bytestream2_put_be16(&pbc, 1);
132  bytestream2_put_byte(&pbc, 0);
133  bytestream2_put_byte(&pbc, 0);
134 
135  /* DQT */
136  jpeg_put_marker(&pbc, DQT);
137  bytestream2_put_be16(&pbc, 2 + nb_qtable * (1 + 64));
138 
139  for (i = 0; i < nb_qtable; i++) {
140  bytestream2_put_byte(&pbc, i);
141 
142  /* Each table is an array of 64 values given in zig-zag
143  * order, identical to the format used in a JFIF DQT
144  * marker segment. */
145  bytestream2_put_buffer(&pbc, qtable + 64 * i, 64);
146  }
147 
148  /* DHT */
149  jpeg_put_marker(&pbc, DHT);
150  dht_size_ptr = pbc.buffer;
151  bytestream2_put_be16(&pbc, 0);
152 
153  dht_size = 2;
162  AV_WB16(dht_size_ptr, dht_size);
163 
164  /* SOF0 */
165  jpeg_put_marker(&pbc, SOF0);
166  bytestream2_put_be16(&pbc, 17); /* size */
167  bytestream2_put_byte(&pbc, 8); /* bits per component */
168  bytestream2_put_be16(&pbc, h);
169  bytestream2_put_be16(&pbc, w);
170  bytestream2_put_byte(&pbc, 3); /* number of components */
171  bytestream2_put_byte(&pbc, 1); /* component number */
172  bytestream2_put_byte(&pbc, (2 << 4) | (type ? 2 : 1)); /* hsample/vsample */
173  bytestream2_put_byte(&pbc, 0); /* matrix number */
174  bytestream2_put_byte(&pbc, 2); /* component number */
175  bytestream2_put_byte(&pbc, 1 << 4 | 1); /* hsample/vsample */
176  bytestream2_put_byte(&pbc, nb_qtable == 2 ? 1 : 0); /* matrix number */
177  bytestream2_put_byte(&pbc, 3); /* component number */
178  bytestream2_put_byte(&pbc, 1 << 4 | 1); /* hsample/vsample */
179  bytestream2_put_byte(&pbc, nb_qtable == 2 ? 1 : 0); /* matrix number */
180 
181  /* SOS */
182  jpeg_put_marker(&pbc, SOS);
183  bytestream2_put_be16(&pbc, 12);
184  bytestream2_put_byte(&pbc, 3);
185  bytestream2_put_byte(&pbc, 1);
186  bytestream2_put_byte(&pbc, 0);
187  bytestream2_put_byte(&pbc, 2);
188  bytestream2_put_byte(&pbc, 17);
189  bytestream2_put_byte(&pbc, 3);
190  bytestream2_put_byte(&pbc, 17);
191  bytestream2_put_byte(&pbc, 0);
192  bytestream2_put_byte(&pbc, 63);
193  bytestream2_put_byte(&pbc, 0);
194 
195  /* Return the length in bytes of the JPEG header. */
196  return bytestream2_tell_p(&pbc);
197 }
198 
199 static void create_default_qtables(uint8_t *qtables, uint8_t q)
200 {
201  int factor = q;
202  int i;
203 
204  factor = av_clip(q, 1, 99);
205 
206  if (q < 50)
207  q = 5000 / factor;
208  else
209  q = 200 - factor * 2;
210 
211  for (i = 0; i < 128; i++) {
212  int val = (default_quantizers[i] * q + 50) / 100;
213 
214  /* Limit the quantizers to 1 <= q <= 255. */
215  val = av_clip(val, 1, 255);
216  qtables[i] = val;
217  }
218 }
219 
221  AVStream *st, AVPacket *pkt, uint32_t *timestamp,
222  const uint8_t *buf, int len, uint16_t seq,
223  int flags)
224 {
225  uint8_t type, q, width, height;
226  const uint8_t *qtables = NULL;
227  uint16_t qtable_len;
228  uint32_t off;
229  int ret;
230 
231  if (len < 8) {
232  av_log(ctx, AV_LOG_ERROR, "Too short RTP/JPEG packet.\n");
233  return AVERROR_INVALIDDATA;
234  }
235 
236  /* Parse the main JPEG header. */
237  off = AV_RB24(buf + 1); /* fragment byte offset */
238  type = AV_RB8(buf + 4); /* id of jpeg decoder params */
239  q = AV_RB8(buf + 5); /* quantization factor (or table id) */
240  width = AV_RB8(buf + 6); /* frame width in 8 pixel blocks */
241  height = AV_RB8(buf + 7); /* frame height in 8 pixel blocks */
242  buf += 8;
243  len -= 8;
244 
245  /* Parse the restart marker header. */
246  if (type > 63) {
247  av_log(ctx, AV_LOG_ERROR,
248  "Unimplemented RTP/JPEG restart marker header.\n");
249  return AVERROR_PATCHWELCOME;
250  }
251  if (type > 1) {
252  av_log(ctx, AV_LOG_ERROR, "Unimplemented RTP/JPEG type %d\n", type);
253  return AVERROR_PATCHWELCOME;
254  }
255 
256  /* Parse the quantization table header. */
257  if (off == 0) {
258  /* Start of JPEG data packet. */
259  uint8_t new_qtables[128];
260  uint8_t hdr[1024];
261 
262  if (q > 127) {
263  uint8_t precision;
264  if (len < 4) {
265  av_log(ctx, AV_LOG_ERROR, "Too short RTP/JPEG packet.\n");
266  return AVERROR_INVALIDDATA;
267  }
268 
269  /* The first byte is reserved for future use. */
270  precision = AV_RB8(buf + 1); /* size of coefficients */
271  qtable_len = AV_RB16(buf + 2); /* length in bytes */
272  buf += 4;
273  len -= 4;
274 
275  if (precision)
276  av_log(ctx, AV_LOG_WARNING, "Only 8-bit precision is supported.\n");
277 
278  if (qtable_len > 0) {
279  if (len < qtable_len) {
280  av_log(ctx, AV_LOG_ERROR, "Too short RTP/JPEG packet.\n");
281  return AVERROR_INVALIDDATA;
282  }
283  qtables = buf;
284  buf += qtable_len;
285  len -= qtable_len;
286  if (q < 255) {
287  if (jpeg->qtables_len[q - 128] &&
288  (jpeg->qtables_len[q - 128] != qtable_len ||
289  memcmp(qtables, &jpeg->qtables[q - 128][0], qtable_len))) {
290  av_log(ctx, AV_LOG_WARNING,
291  "Quantization tables for q=%d changed\n", q);
292  } else if (!jpeg->qtables_len[q - 128] && qtable_len <= 128) {
293  memcpy(&jpeg->qtables[q - 128][0], qtables,
294  qtable_len);
295  jpeg->qtables_len[q - 128] = qtable_len;
296  }
297  }
298  } else {
299  if (q == 255) {
300  av_log(ctx, AV_LOG_ERROR,
301  "Invalid RTP/JPEG packet. Quantization tables not found.\n");
302  return AVERROR_INVALIDDATA;
303  }
304  if (!jpeg->qtables_len[q - 128]) {
305  av_log(ctx, AV_LOG_ERROR,
306  "No quantization tables known for q=%d yet.\n", q);
307  return AVERROR_INVALIDDATA;
308  }
309  qtables = &jpeg->qtables[q - 128][0];
310  qtable_len = jpeg->qtables_len[q - 128];
311  }
312  } else { /* q <= 127 */
313  if (q == 0 || q > 99) {
314  av_log(ctx, AV_LOG_ERROR, "Reserved q value %d\n", q);
315  return AVERROR_INVALIDDATA;
316  }
317  create_default_qtables(new_qtables, q);
318  qtables = new_qtables;
319  qtable_len = sizeof(new_qtables);
320  }
321 
322  /* Skip the current frame in case of the end packet
323  * has been lost somewhere. */
324  free_frame_if_needed(jpeg);
325 
326  if ((ret = avio_open_dyn_buf(&jpeg->frame)) < 0)
327  return ret;
328  jpeg->timestamp = *timestamp;
329 
330  /* Generate a frame and scan headers that can be prepended to the
331  * RTP/JPEG data payload to produce a JPEG compressed image in
332  * interchange format. */
333  jpeg->hdr_size = jpeg_create_header(hdr, sizeof(hdr), type, width,
334  height, qtables,
335  qtable_len / 64);
336 
337  /* Copy JPEG header to frame buffer. */
338  avio_write(jpeg->frame, hdr, jpeg->hdr_size);
339  }
340 
341  if (!jpeg->frame) {
342  av_log(ctx, AV_LOG_ERROR,
343  "Received packet without a start chunk; dropping frame.\n");
344  return AVERROR(EAGAIN);
345  }
346 
347  if (jpeg->timestamp != *timestamp) {
348  /* Skip the current frame if timestamp is incorrect.
349  * A start packet has been lost somewhere. */
350  free_frame_if_needed(jpeg);
351  av_log(ctx, AV_LOG_ERROR, "RTP timestamps don't match.\n");
352  return AVERROR_INVALIDDATA;
353  }
354 
355  if (off != avio_tell(jpeg->frame) - jpeg->hdr_size) {
356  av_log(ctx, AV_LOG_ERROR,
357  "Missing packets; dropping frame.\n");
358  return AVERROR(EAGAIN);
359  }
360 
361  /* Copy data to frame buffer. */
362  avio_write(jpeg->frame, buf, len);
363 
364  if (flags & RTP_FLAG_MARKER) {
365  /* End of JPEG data packet. */
366  uint8_t buf[2] = { 0xff, EOI };
367 
368  /* Put EOI marker. */
369  avio_write(jpeg->frame, buf, sizeof(buf));
370 
371  /* Prepare the JPEG packet. */
372  if ((ret = ff_rtp_finalize_packet(pkt, &jpeg->frame, st->index)) < 0) {
373  av_log(ctx, AV_LOG_ERROR,
374  "Error occurred when getting frame buffer.\n");
375  return ret;
376  }
377 
378  return 0;
379  }
380 
381  return AVERROR(EAGAIN);
382 }
383 
385  .enc_name = "JPEG",
386  .codec_type = AVMEDIA_TYPE_VIDEO,
387  .codec_id = AV_CODEC_ID_MJPEG,
388  .alloc = jpeg_new_context,
389  .free = jpeg_free_context,
390  .parse_packet = jpeg_parse_packet,
391  .static_payload_id = 26,
392 };