2 * RTP JPEG-compressed Video Depacketizer, RFC 2435
3 * Copyright (c) 2012 Samuel Pitoiset
5 * This file is part of FFmpeg.
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.
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.
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
23 #include "rtpdec_formats.h"
24 #include "libavutil/intreadwrite.h"
25 #include "libavcodec/mjpeg.h"
26 #include "libavcodec/bytestream.h"
29 * RTP/JPEG specific private data.
31 struct PayloadContext {
32 AVIOContext *frame; ///< current frame buffer
33 uint32_t timestamp; ///< current frame timestamp
34 int hdr_size; ///< size of the current frame header
35 uint8_t qtables[128][128];
36 uint8_t qtables_len[128];
39 static const uint8_t default_quantizers[128] = {
41 16, 11, 12, 14, 12, 10, 16, 14,
42 13, 14, 18, 17, 16, 19, 24, 40,
43 26, 24, 22, 22, 24, 49, 35, 37,
44 29, 40, 58, 51, 61, 60, 57, 51,
45 56, 55, 64, 72, 92, 78, 64, 68,
46 87, 69, 55, 56, 80, 109, 81, 87,
47 95, 98, 103, 104, 103, 62, 77, 113,
48 121, 112, 100, 120, 92, 101, 103, 99,
51 17, 18, 18, 24, 21, 24, 47, 26,
52 26, 47, 99, 66, 56, 66, 99, 99,
53 99, 99, 99, 99, 99, 99, 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
61 static PayloadContext *jpeg_new_context(void)
63 return av_mallocz(sizeof(PayloadContext));
66 static inline void free_frame_if_needed(PayloadContext *jpeg)
70 avio_close_dyn_buf(jpeg->frame, &p);
76 static void jpeg_free_context(PayloadContext *jpeg)
78 free_frame_if_needed(jpeg);
82 static int jpeg_create_huffman_table(PutByteContext *p, int table_class,
83 int table_id, const uint8_t *bits_table,
84 const uint8_t *value_table)
88 bytestream2_put_byte(p, table_class << 4 | table_id);
90 for (i = 1; i <= 16; i++) {
92 bytestream2_put_byte(p, bits_table[i]);
95 for (i = 0; i < n; i++) {
96 bytestream2_put_byte(p, value_table[i]);
101 static void jpeg_put_marker(PutByteContext *pbc, int code)
103 bytestream2_put_byte(pbc, 0xff);
104 bytestream2_put_byte(pbc, code);
107 static int jpeg_create_header(uint8_t *buf, int size, uint32_t type, uint32_t w,
108 uint32_t h, const uint8_t *qtable, int nb_qtable)
111 uint8_t *dht_size_ptr;
114 bytestream2_init_writer(&pbc, buf, size);
116 /* Convert from blocks to pixels. */
121 jpeg_put_marker(&pbc, SOI);
124 jpeg_put_marker(&pbc, APP0);
125 bytestream2_put_be16(&pbc, 16);
126 bytestream2_put_buffer(&pbc, "JFIF", 5);
127 bytestream2_put_be16(&pbc, 0x0201);
128 bytestream2_put_byte(&pbc, 0);
129 bytestream2_put_be16(&pbc, 1);
130 bytestream2_put_be16(&pbc, 1);
131 bytestream2_put_byte(&pbc, 0);
132 bytestream2_put_byte(&pbc, 0);
135 jpeg_put_marker(&pbc, DQT);
136 bytestream2_put_be16(&pbc, 2 + nb_qtable * (1 + 64));
138 for (i = 0; i < nb_qtable; i++) {
139 bytestream2_put_byte(&pbc, i);
141 /* Each table is an array of 64 values given in zig-zag
142 * order, identical to the format used in a JFIF DQT
144 bytestream2_put_buffer(&pbc, qtable + 64 * i, 64);
148 jpeg_put_marker(&pbc, DHT);
149 dht_size_ptr = pbc.buffer;
150 bytestream2_put_be16(&pbc, 0);
153 dht_size += jpeg_create_huffman_table(&pbc, 0, 0,avpriv_mjpeg_bits_dc_luminance,
154 avpriv_mjpeg_val_dc);
155 dht_size += jpeg_create_huffman_table(&pbc, 0, 1, avpriv_mjpeg_bits_dc_chrominance,
156 avpriv_mjpeg_val_dc);
157 dht_size += jpeg_create_huffman_table(&pbc, 1, 0, avpriv_mjpeg_bits_ac_luminance,
158 avpriv_mjpeg_val_ac_luminance);
159 dht_size += jpeg_create_huffman_table(&pbc, 1, 1, avpriv_mjpeg_bits_ac_chrominance,
160 avpriv_mjpeg_val_ac_chrominance);
161 AV_WB16(dht_size_ptr, dht_size);
164 jpeg_put_marker(&pbc, SOF0);
165 bytestream2_put_be16(&pbc, 17); /* size */
166 bytestream2_put_byte(&pbc, 8); /* bits per component */
167 bytestream2_put_be16(&pbc, h);
168 bytestream2_put_be16(&pbc, w);
169 bytestream2_put_byte(&pbc, 3); /* number of components */
170 bytestream2_put_byte(&pbc, 1); /* component number */
171 bytestream2_put_byte(&pbc, (2 << 4) | (type ? 2 : 1)); /* hsample/vsample */
172 bytestream2_put_byte(&pbc, 0); /* matrix number */
173 bytestream2_put_byte(&pbc, 2); /* component number */
174 bytestream2_put_byte(&pbc, 1 << 4 | 1); /* hsample/vsample */
175 bytestream2_put_byte(&pbc, nb_qtable == 2 ? 1 : 0); /* matrix number */
176 bytestream2_put_byte(&pbc, 3); /* component number */
177 bytestream2_put_byte(&pbc, 1 << 4 | 1); /* hsample/vsample */
178 bytestream2_put_byte(&pbc, nb_qtable == 2 ? 1 : 0); /* matrix number */
181 jpeg_put_marker(&pbc, SOS);
182 bytestream2_put_be16(&pbc, 12);
183 bytestream2_put_byte(&pbc, 3);
184 bytestream2_put_byte(&pbc, 1);
185 bytestream2_put_byte(&pbc, 0);
186 bytestream2_put_byte(&pbc, 2);
187 bytestream2_put_byte(&pbc, 17);
188 bytestream2_put_byte(&pbc, 3);
189 bytestream2_put_byte(&pbc, 17);
190 bytestream2_put_byte(&pbc, 0);
191 bytestream2_put_byte(&pbc, 63);
192 bytestream2_put_byte(&pbc, 0);
194 /* Return the length in bytes of the JPEG header. */
195 return bytestream2_tell_p(&pbc);
198 static void create_default_qtables(uint8_t *qtables, uint8_t q)
203 factor = av_clip(q, 1, 99);
208 q = 200 - factor * 2;
210 for (i = 0; i < 128; i++) {
211 int val = (default_quantizers[i] * q + 50) / 100;
213 /* Limit the quantizers to 1 <= q <= 255. */
214 val = av_clip(val, 1, 255);
219 static int jpeg_parse_packet(AVFormatContext *ctx, PayloadContext *jpeg,
220 AVStream *st, AVPacket *pkt, uint32_t *timestamp,
221 const uint8_t *buf, int len, int flags)
223 uint8_t type, q, width, height;
224 const uint8_t *qtables = NULL;
230 av_log(ctx, AV_LOG_ERROR, "Too short RTP/JPEG packet.\n");
231 return AVERROR_INVALIDDATA;
234 /* Parse the main JPEG header. */
235 off = AV_RB24(buf + 1); /* fragment byte offset */
236 type = AV_RB8(buf + 4); /* id of jpeg decoder params */
237 q = AV_RB8(buf + 5); /* quantization factor (or table id) */
238 width = AV_RB8(buf + 6); /* frame width in 8 pixel blocks */
239 height = AV_RB8(buf + 7); /* frame height in 8 pixel blocks */
243 /* Parse the restart marker header. */
245 av_log(ctx, AV_LOG_ERROR,
246 "Unimplemented RTP/JPEG restart marker header.\n");
247 return AVERROR_PATCHWELCOME;
250 av_log(ctx, AV_LOG_ERROR, "Unimplemented RTP/JPEG type %d\n", type);
251 return AVERROR_PATCHWELCOME;
254 /* Parse the quantization table header. */
256 /* Start of JPEG data packet. */
257 uint8_t new_qtables[128];
263 av_log(ctx, AV_LOG_ERROR, "Too short RTP/JPEG packet.\n");
264 return AVERROR_INVALIDDATA;
267 /* The first byte is reserved for future use. */
268 precision = AV_RB8(buf + 1); /* size of coefficients */
269 qtable_len = AV_RB16(buf + 2); /* length in bytes */
274 av_log(ctx, AV_LOG_WARNING, "Only 8-bit precision is supported.\n");
276 if (qtable_len > 0) {
277 if (len < qtable_len) {
278 av_log(ctx, AV_LOG_ERROR, "Too short RTP/JPEG packet.\n");
279 return AVERROR_INVALIDDATA;
285 if (jpeg->qtables_len[q - 128] &&
286 (jpeg->qtables_len[q - 128] != qtable_len ||
287 memcmp(qtables, &jpeg->qtables[q - 128][0], qtable_len))) {
288 av_log(ctx, AV_LOG_WARNING,
289 "Quantization tables for q=%d changed\n", q);
290 } else if (!jpeg->qtables_len[q - 128] && qtable_len <= 128) {
291 memcpy(&jpeg->qtables[q - 128][0], qtables,
293 jpeg->qtables_len[q - 128] = qtable_len;
298 av_log(ctx, AV_LOG_ERROR,
299 "Invalid RTP/JPEG packet. Quantization tables not found.\n");
300 return AVERROR_INVALIDDATA;
302 if (!jpeg->qtables_len[q - 128]) {
303 av_log(ctx, AV_LOG_ERROR,
304 "No quantization tables known for q=%d yet.\n", q);
305 return AVERROR_INVALIDDATA;
307 qtables = &jpeg->qtables[q - 128][0];
308 qtable_len = jpeg->qtables_len[q - 128];
310 } else { /* q <= 127 */
311 if (q == 0 || q > 99) {
312 av_log(ctx, AV_LOG_ERROR, "Reserved q value %d\n", q);
313 return AVERROR_INVALIDDATA;
315 create_default_qtables(new_qtables, q);
316 qtables = new_qtables;
317 qtable_len = sizeof(new_qtables);
320 /* Skip the current frame in case of the end packet
321 * has been lost somewhere. */
322 free_frame_if_needed(jpeg);
324 if ((ret = avio_open_dyn_buf(&jpeg->frame)) < 0)
326 jpeg->timestamp = *timestamp;
328 /* Generate a frame and scan headers that can be prepended to the
329 * RTP/JPEG data payload to produce a JPEG compressed image in
330 * interchange format. */
331 jpeg->hdr_size = jpeg_create_header(hdr, sizeof(hdr), type, width,
335 /* Copy JPEG header to frame buffer. */
336 avio_write(jpeg->frame, hdr, jpeg->hdr_size);
340 av_log(ctx, AV_LOG_ERROR,
341 "Received packet without a start chunk; dropping frame.\n");
342 return AVERROR(EAGAIN);
345 if (jpeg->timestamp != *timestamp) {
346 /* Skip the current frame if timestamp is incorrect.
347 * A start packet has been lost somewhere. */
348 free_frame_if_needed(jpeg);
349 av_log(ctx, AV_LOG_ERROR, "RTP timestamps don't match.\n");
350 return AVERROR_INVALIDDATA;
353 if (off != avio_tell(jpeg->frame) - jpeg->hdr_size) {
354 av_log(ctx, AV_LOG_ERROR,
355 "Missing packets; dropping frame.\n");
356 return AVERROR(EAGAIN);
359 /* Copy data to frame buffer. */
360 avio_write(jpeg->frame, buf, len);
362 if (flags & RTP_FLAG_MARKER) {
363 /* End of JPEG data packet. */
364 uint8_t buf[2] = { 0xff, EOI };
366 /* Put EOI marker. */
367 avio_write(jpeg->frame, buf, sizeof(buf));
369 /* Prepare the JPEG packet. */
371 pkt->size = avio_close_dyn_buf(jpeg->frame, &pkt->data);
373 av_log(ctx, AV_LOG_ERROR,
374 "Error occured when getting frame buffer.\n");
378 pkt->stream_index = st->index;
379 pkt->destruct = av_destruct_packet;
381 /* Re-init the frame buffer. */
387 return AVERROR(EAGAIN);
390 RTPDynamicProtocolHandler ff_jpeg_dynamic_handler = {
392 .codec_type = AVMEDIA_TYPE_VIDEO,
393 .codec_id = AV_CODEC_ID_MJPEG,
394 .alloc = jpeg_new_context,
395 .free = jpeg_free_context,
396 .parse_packet = jpeg_parse_packet,
397 .static_payload_id = 26,