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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];
37  uint8_t qtables_len[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 
62 static PayloadContext *jpeg_new_context(void)
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 
77 static void jpeg_free_context(PayloadContext *jpeg)
78 {
79  free_frame_if_needed(jpeg);
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  int dri)
111 {
112  PutByteContext pbc;
113  uint8_t *dht_size_ptr;
114  int dht_size, i;
115 
116  bytestream2_init_writer(&pbc, buf, size);
117 
118  /* Convert from blocks to pixels. */
119  w <<= 3;
120  h <<= 3;
121 
122  /* SOI */
123  jpeg_put_marker(&pbc, SOI);
124 
125  /* JFIF header */
126  jpeg_put_marker(&pbc, APP0);
127  bytestream2_put_be16(&pbc, 16);
128  bytestream2_put_buffer(&pbc, "JFIF", 5);
129  bytestream2_put_be16(&pbc, 0x0201);
130  bytestream2_put_byte(&pbc, 0);
131  bytestream2_put_be16(&pbc, 1);
132  bytestream2_put_be16(&pbc, 1);
133  bytestream2_put_byte(&pbc, 0);
134  bytestream2_put_byte(&pbc, 0);
135 
136  if (dri) {
137  jpeg_put_marker(&pbc, DRI);
138  bytestream2_put_be16(&pbc, 4);
139  bytestream2_put_be16(&pbc, dri);
140  }
141 
142  /* DQT */
143  jpeg_put_marker(&pbc, DQT);
144  bytestream2_put_be16(&pbc, 2 + nb_qtable * (1 + 64));
145 
146  for (i = 0; i < nb_qtable; i++) {
147  bytestream2_put_byte(&pbc, i);
148 
149  /* Each table is an array of 64 values given in zig-zag
150  * order, identical to the format used in a JFIF DQT
151  * marker segment. */
152  bytestream2_put_buffer(&pbc, qtable + 64 * i, 64);
153  }
154 
155  /* DHT */
156  jpeg_put_marker(&pbc, DHT);
157  dht_size_ptr = pbc.buffer;
158  bytestream2_put_be16(&pbc, 0);
159 
160  dht_size = 2;
161  dht_size += jpeg_create_huffman_table(&pbc, 0, 0,avpriv_mjpeg_bits_dc_luminance,
162  avpriv_mjpeg_val_dc);
163  dht_size += jpeg_create_huffman_table(&pbc, 0, 1, avpriv_mjpeg_bits_dc_chrominance,
164  avpriv_mjpeg_val_dc);
165  dht_size += jpeg_create_huffman_table(&pbc, 1, 0, avpriv_mjpeg_bits_ac_luminance,
166  avpriv_mjpeg_val_ac_luminance);
167  dht_size += jpeg_create_huffman_table(&pbc, 1, 1, avpriv_mjpeg_bits_ac_chrominance,
168  avpriv_mjpeg_val_ac_chrominance);
169  AV_WB16(dht_size_ptr, dht_size);
170 
171  /* SOF0 */
172  jpeg_put_marker(&pbc, SOF0);
173  bytestream2_put_be16(&pbc, 17); /* size */
174  bytestream2_put_byte(&pbc, 8); /* bits per component */
175  bytestream2_put_be16(&pbc, h);
176  bytestream2_put_be16(&pbc, w);
177  bytestream2_put_byte(&pbc, 3); /* number of components */
178  bytestream2_put_byte(&pbc, 1); /* component number */
179  bytestream2_put_byte(&pbc, (2 << 4) | (type ? 2 : 1)); /* hsample/vsample */
180  bytestream2_put_byte(&pbc, 0); /* matrix number */
181  bytestream2_put_byte(&pbc, 2); /* component number */
182  bytestream2_put_byte(&pbc, 1 << 4 | 1); /* hsample/vsample */
183  bytestream2_put_byte(&pbc, nb_qtable == 2 ? 1 : 0); /* matrix number */
184  bytestream2_put_byte(&pbc, 3); /* component number */
185  bytestream2_put_byte(&pbc, 1 << 4 | 1); /* hsample/vsample */
186  bytestream2_put_byte(&pbc, nb_qtable == 2 ? 1 : 0); /* matrix number */
187 
188  /* SOS */
189  jpeg_put_marker(&pbc, SOS);
190  bytestream2_put_be16(&pbc, 12);
191  bytestream2_put_byte(&pbc, 3);
192  bytestream2_put_byte(&pbc, 1);
193  bytestream2_put_byte(&pbc, 0);
194  bytestream2_put_byte(&pbc, 2);
195  bytestream2_put_byte(&pbc, 17);
196  bytestream2_put_byte(&pbc, 3);
197  bytestream2_put_byte(&pbc, 17);
198  bytestream2_put_byte(&pbc, 0);
199  bytestream2_put_byte(&pbc, 63);
200  bytestream2_put_byte(&pbc, 0);
201 
202  /* Return the length in bytes of the JPEG header. */
203  return bytestream2_tell_p(&pbc);
204 }
205 
206 static void create_default_qtables(uint8_t *qtables, uint8_t q)
207 {
208  int factor = q;
209  int i;
210 
211  factor = av_clip(q, 1, 99);
212 
213  if (q < 50)
214  q = 5000 / factor;
215  else
216  q = 200 - factor * 2;
217 
218  for (i = 0; i < 128; i++) {
219  int val = (default_quantizers[i] * q + 50) / 100;
220 
221  /* Limit the quantizers to 1 <= q <= 255. */
222  val = av_clip(val, 1, 255);
223  qtables[i] = val;
224  }
225 }
226 
227 static int jpeg_parse_packet(AVFormatContext *ctx, PayloadContext *jpeg,
228  AVStream *st, AVPacket *pkt, uint32_t *timestamp,
229  const uint8_t *buf, int len, uint16_t seq,
230  int flags)
231 {
232  uint8_t type, q, width, height;
233  const uint8_t *qtables = NULL;
234  uint16_t qtable_len;
235  uint32_t off;
236  int ret, dri = 0;
237 
238  if (len < 8) {
239  av_log(ctx, AV_LOG_ERROR, "Too short RTP/JPEG packet.\n");
240  return AVERROR_INVALIDDATA;
241  }
242 
243  /* Parse the main JPEG header. */
244  off = AV_RB24(buf + 1); /* fragment byte offset */
245  type = AV_RB8(buf + 4); /* id of jpeg decoder params */
246  q = AV_RB8(buf + 5); /* quantization factor (or table id) */
247  width = AV_RB8(buf + 6); /* frame width in 8 pixel blocks */
248  height = AV_RB8(buf + 7); /* frame height in 8 pixel blocks */
249  buf += 8;
250  len -= 8;
251 
252  if (type & 0x40) {
253  if (len < 4) {
254  av_log(ctx, AV_LOG_ERROR, "Too short RTP/JPEG packet.\n");
255  return AVERROR_INVALIDDATA;
256  }
257  dri = AV_RB16(buf);
258  buf += 4;
259  len -= 4;
260  type &= ~0x40;
261  }
262  /* Parse the restart marker header. */
263  if (type > 63) {
264  av_log(ctx, AV_LOG_ERROR,
265  "Unimplemented RTP/JPEG restart marker header.\n");
266  return AVERROR_PATCHWELCOME;
267  }
268  if (type > 1) {
269  av_log(ctx, AV_LOG_ERROR, "Unimplemented RTP/JPEG type %d\n", type);
270  return AVERROR_PATCHWELCOME;
271  }
272 
273  /* Parse the quantization table header. */
274  if (off == 0) {
275  /* Start of JPEG data packet. */
276  uint8_t new_qtables[128];
277  uint8_t hdr[1024];
278 
279  if (q > 127) {
280  uint8_t precision;
281  if (len < 4) {
282  av_log(ctx, AV_LOG_ERROR, "Too short RTP/JPEG packet.\n");
283  return AVERROR_INVALIDDATA;
284  }
285 
286  /* The first byte is reserved for future use. */
287  precision = AV_RB8(buf + 1); /* size of coefficients */
288  qtable_len = AV_RB16(buf + 2); /* length in bytes */
289  buf += 4;
290  len -= 4;
291 
292  if (precision)
293  av_log(ctx, AV_LOG_WARNING, "Only 8-bit precision is supported.\n");
294 
295  if (qtable_len > 0) {
296  if (len < qtable_len) {
297  av_log(ctx, AV_LOG_ERROR, "Too short RTP/JPEG packet.\n");
298  return AVERROR_INVALIDDATA;
299  }
300  qtables = buf;
301  buf += qtable_len;
302  len -= qtable_len;
303  if (q < 255) {
304  if (jpeg->qtables_len[q - 128] &&
305  (jpeg->qtables_len[q - 128] != qtable_len ||
306  memcmp(qtables, &jpeg->qtables[q - 128][0], qtable_len))) {
307  av_log(ctx, AV_LOG_WARNING,
308  "Quantization tables for q=%d changed\n", q);
309  } else if (!jpeg->qtables_len[q - 128] && qtable_len <= 128) {
310  memcpy(&jpeg->qtables[q - 128][0], qtables,
311  qtable_len);
312  jpeg->qtables_len[q - 128] = qtable_len;
313  }
314  }
315  } else {
316  if (q == 255) {
317  av_log(ctx, AV_LOG_ERROR,
318  "Invalid RTP/JPEG packet. Quantization tables not found.\n");
319  return AVERROR_INVALIDDATA;
320  }
321  if (!jpeg->qtables_len[q - 128]) {
322  av_log(ctx, AV_LOG_ERROR,
323  "No quantization tables known for q=%d yet.\n", q);
324  return AVERROR_INVALIDDATA;
325  }
326  qtables = &jpeg->qtables[q - 128][0];
327  qtable_len = jpeg->qtables_len[q - 128];
328  }
329  } else { /* q <= 127 */
330  if (q == 0 || q > 99) {
331  av_log(ctx, AV_LOG_ERROR, "Reserved q value %d\n", q);
332  return AVERROR_INVALIDDATA;
333  }
334  create_default_qtables(new_qtables, q);
335  qtables = new_qtables;
336  qtable_len = sizeof(new_qtables);
337  }
338 
339  /* Skip the current frame in case of the end packet
340  * has been lost somewhere. */
341  free_frame_if_needed(jpeg);
342 
343  if ((ret = avio_open_dyn_buf(&jpeg->frame)) < 0)
344  return ret;
345  jpeg->timestamp = *timestamp;
346 
347  /* Generate a frame and scan headers that can be prepended to the
348  * RTP/JPEG data payload to produce a JPEG compressed image in
349  * interchange format. */
350  jpeg->hdr_size = jpeg_create_header(hdr, sizeof(hdr), type, width,
351  height, qtables,
352  qtable_len / 64, dri);
353 
354  /* Copy JPEG header to frame buffer. */
355  avio_write(jpeg->frame, hdr, jpeg->hdr_size);
356  }
357 
358  if (!jpeg->frame) {
359  av_log(ctx, AV_LOG_ERROR,
360  "Received packet without a start chunk; dropping frame.\n");
361  return AVERROR(EAGAIN);
362  }
363 
364  if (jpeg->timestamp != *timestamp) {
365  /* Skip the current frame if timestamp is incorrect.
366  * A start packet has been lost somewhere. */
367  free_frame_if_needed(jpeg);
368  av_log(ctx, AV_LOG_ERROR, "RTP timestamps don't match.\n");
369  return AVERROR_INVALIDDATA;
370  }
371 
372  if (off != avio_tell(jpeg->frame) - jpeg->hdr_size) {
373  av_log(ctx, AV_LOG_ERROR,
374  "Missing packets; dropping frame.\n");
375  return AVERROR(EAGAIN);
376  }
377 
378  /* Copy data to frame buffer. */
379  avio_write(jpeg->frame, buf, len);
380 
381  if (flags & RTP_FLAG_MARKER) {
382  /* End of JPEG data packet. */
383  uint8_t buf[2] = { 0xff, EOI };
384 
385  /* Put EOI marker. */
386  avio_write(jpeg->frame, buf, sizeof(buf));
387 
388  /* Prepare the JPEG packet. */
389  if ((ret = ff_rtp_finalize_packet(pkt, &jpeg->frame, st->index)) < 0) {
390  av_log(ctx, AV_LOG_ERROR,
391  "Error occurred when getting frame buffer.\n");
392  return ret;
393  }
394 
395  return 0;
396  }
397 
398  return AVERROR(EAGAIN);
399 }
400 
401 RTPDynamicProtocolHandler ff_jpeg_dynamic_handler = {
402  .enc_name = "JPEG",
403  .codec_type = AVMEDIA_TYPE_VIDEO,
404  .codec_id = AV_CODEC_ID_MJPEG,
405  .alloc = jpeg_new_context,
406  .free = jpeg_free_context,
407  .parse_packet = jpeg_parse_packet,
408  .static_payload_id = 26,
409 };
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