FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavformat/rtpdec_h264.c
Date: 2026-09-25 17:25:24
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Lines: 0 177 0.0%
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Branches: 0 91 0.0%

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1 /*
2 * RTP H.264 Protocol (RFC3984)
3 * Copyright (c) 2006 Ryan Martell
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 * @file
24 * @brief H.264 / RTP Code (RFC3984)
25 * @author Ryan Martell <rdm4@martellventures.com>
26 *
27 * @note Notes:
28 * Notes:
29 * This currently supports packetization mode:
30 * Single Nal Unit Mode (0), or
31 * Non-Interleaved Mode (1). It currently does not support
32 * Interleaved Mode (2). (This requires implementing STAP-B, MTAP16, MTAP24,
33 * FU-B packet types)
34 */
35
36 #include "libavutil/attributes.h"
37 #include "libavutil/base64.h"
38 #include "libavutil/intreadwrite.h"
39 #include "libavutil/avstring.h"
40 #include "libavutil/mem.h"
41 #include "avformat.h"
42
43 #include "rtpdec.h"
44 #include "rtpdec_formats.h"
45
46 struct PayloadContext {
47 // sdp setup parameters
48 uint8_t profile_idc;
49 uint8_t profile_iop;
50 uint8_t level_idc;
51 int packetization_mode;
52 #ifdef DEBUG
53 int packet_types_received[32];
54 #endif
55 };
56
57 #ifdef DEBUG
58 #define COUNT_NAL_TYPE(data, nal) data->packet_types_received[(nal) & 0x1f]++
59 #define NAL_COUNTERS data->packet_types_received
60 #else
61 #define COUNT_NAL_TYPE(data, nal) do { } while (0)
62 #define NAL_COUNTERS NULL
63 #endif
64 #define NAL_MASK 0x1f
65
66 static const uint8_t start_sequence[] = { 0, 0, 0, 1 };
67
68 ✗ static void parse_profile_level_id(AVFormatContext *s,
69 PayloadContext *h264_data,
70 const char *value)
71 {
72 char buffer[3];
73 // 6 characters=3 bytes, in hex.
74 uint8_t profile_idc;
75 uint8_t profile_iop;
76 uint8_t level_idc;
77
78 ✗ buffer[0] = value[0];
79 ✗ buffer[1] = value[1];
80 ✗ buffer[2] = '\0';
81 ✗ profile_idc = strtol(buffer, NULL, 16);
82 ✗ buffer[0] = value[2];
83 ✗ buffer[1] = value[3];
84 ✗ profile_iop = strtol(buffer, NULL, 16);
85 ✗ buffer[0] = value[4];
86 ✗ buffer[1] = value[5];
87 ✗ level_idc = strtol(buffer, NULL, 16);
88
89 ✗ av_log(s, AV_LOG_DEBUG,
90 "RTP Profile IDC: %x Profile IOP: %x Level: %x\n",
91 profile_idc, profile_iop, level_idc);
92 ✗ h264_data->profile_idc = profile_idc;
93 ✗ h264_data->profile_iop = profile_iop;
94 ✗ h264_data->level_idc = level_idc;
95 ✗ }
96
97 ✗ int ff_h264_parse_sprop_parameter_sets(AVFormatContext *s,
98 uint8_t **data_ptr, int *size_ptr,
99 const char *value)
100 {
101 char base64packet[1024];
102 uint8_t decoded_packet[1024];
103 int packet_size;
104
105 ✗ while (*value) {
106 ✗ char *dst = base64packet;
107
108 ✗ while (*value && *value != ','
109 ✗ && (dst - base64packet) < sizeof(base64packet) - 1) {
110 ✗ *dst++ = *value++;
111 }
112 ✗ *dst++ = '\0';
113
114 ✗ if (*value == ',')
115 ✗ value++;
116
117 ✗ packet_size = av_base64_decode(decoded_packet, base64packet,
118 sizeof(decoded_packet));
119 ✗ if (packet_size > 0) {
120 ✗ uint8_t *dest = av_realloc(*data_ptr,
121 ✗ packet_size + sizeof(start_sequence) +
122 ✗ *size_ptr +
123 AV_INPUT_BUFFER_PADDING_SIZE);
124 ✗ if (!dest) {
125 ✗ av_log(s, AV_LOG_ERROR,
126 "Unable to allocate memory for extradata!\n");
127 ✗ return AVERROR(ENOMEM);
128 }
129 ✗ *data_ptr = dest;
130
131 ✗ memcpy(dest + *size_ptr, start_sequence,
132 sizeof(start_sequence));
133 ✗ memcpy(dest + *size_ptr + sizeof(start_sequence),
134 decoded_packet, packet_size);
135 ✗ memset(dest + *size_ptr + sizeof(start_sequence) +
136 packet_size, 0, AV_INPUT_BUFFER_PADDING_SIZE);
137
138 ✗ *size_ptr += sizeof(start_sequence) + packet_size;
139 }
140 }
141
142 ✗ return 0;
143 }
144
145 ✗ static int sdp_parse_fmtp_config_h264(AVFormatContext *s,
146 AVStream *stream,
147 PayloadContext *h264_data,
148 const char *attr, const char *value)
149 {
150 ✗ AVCodecParameters *par = stream->codecpar;
151
152 ✗ if (!strcmp(attr, "packetization-mode")) {
153 ✗ av_log(s, AV_LOG_DEBUG, "RTP Packetization Mode: %d\n", atoi(value));
154 ✗ h264_data->packetization_mode = atoi(value);
155 /*
156 * Packetization Mode:
157 * 0 or not present: Single NAL mode (Only nals from 1-23 are allowed)
158 * 1: Non-interleaved Mode: 1-23, 24 (STAP-A), 28 (FU-A) are allowed.
159 * 2: Interleaved Mode: 25 (STAP-B), 26 (MTAP16), 27 (MTAP24), 28 (FU-A),
160 * and 29 (FU-B) are allowed.
161 */
162 ✗ if (h264_data->packetization_mode > 1)
163 ✗ av_log(s, AV_LOG_ERROR,
164 "Interleaved RTP mode is not supported yet.\n");
165 ✗ } else if (!strcmp(attr, "profile-level-id")) {
166 ✗ if (strlen(value) == 6)
167 ✗ parse_profile_level_id(s, h264_data, value);
168 ✗ } else if (!strcmp(attr, "sprop-parameter-sets")) {
169 int ret;
170 ✗ if (*value == 0 || value[strlen(value) - 1] == ',') {
171 ✗ av_log(s, AV_LOG_WARNING, "Missing PPS in sprop-parameter-sets, ignoring\n");
172 ✗ return 0;
173 }
174 ✗ par->extradata_size = 0;
175 ✗ av_freep(&par->extradata);
176 ✗ ret = ff_h264_parse_sprop_parameter_sets(s, &par->extradata,
177 &par->extradata_size, value);
178 ✗ av_log(s, AV_LOG_DEBUG, "Extradata set to %p (size: %d)\n",
179 par->extradata, par->extradata_size);
180 ✗ return ret;
181 }
182 ✗ return 0;
183 }
184
185 ✗ void ff_h264_parse_framesize(AVCodecParameters *par, const char *p)
186 {
187 char buf1[50];
188 ✗ char *dst = buf1;
189
190 // remove the protocol identifier
191 ✗ while (*p && *p == ' ')
192 ✗ p++; // strip spaces.
193 ✗ while (*p && *p != ' ')
194 ✗ p++; // eat protocol identifier
195 ✗ while (*p && *p == ' ')
196 ✗ p++; // strip trailing spaces.
197 ✗ while (*p && *p != '-' && (dst - buf1) < sizeof(buf1) - 1)
198 ✗ *dst++ = *p++;
199 ✗ *dst = '\0';
200
201 // a='framesize:96 320-240'
202 // set our parameters
203 ✗ par->width = atoi(buf1);
204 ✗ par->height = atoi(p + 1); // skip the -
205 ✗ }
206
207 ✗ int ff_h264_handle_aggregated_packet(AVFormatContext *ctx, PayloadContext *data, AVPacket *pkt,
208 const uint8_t *buf, int len,
209 int skip_between, int *nal_counters,
210 int nal_mask)
211 {
212 ✗ int pass = 0;
213 ✗ int total_length = 0;
214 ✗ uint8_t *dst = NULL;
215 int ret;
216
217 // first we are going to figure out the total size
218 ✗ for (pass = 0; pass < 2; pass++) {
219 ✗ const uint8_t *src = buf;
220 ✗ int src_len = len;
221
222 ✗ while (src_len > 2) {
223 ✗ uint16_t nal_size = AV_RB16(src);
224
225 // consume the length of the aggregate
226 ✗ src += 2;
227 ✗ src_len -= 2;
228
229 ✗ if (nal_size <= src_len) {
230 ✗ if (pass == 0) {
231 // counting
232 ✗ total_length += sizeof(start_sequence) + nal_size;
233 } else {
234 // copying
235 ✗ memcpy(dst, start_sequence, sizeof(start_sequence));
236 ✗ dst += sizeof(start_sequence);
237 ✗ memcpy(dst, src, nal_size);
238 ✗ if (nal_counters)
239 ✗ nal_counters[(*src) & nal_mask]++;
240 ✗ dst += nal_size;
241 }
242 } else {
243 ✗ av_log(ctx, AV_LOG_ERROR,
244 "nal size exceeds length: %d %d\n", nal_size, src_len);
245 ✗ return AVERROR_INVALIDDATA;
246 }
247
248 // eat what we handled
249 ✗ src += nal_size + skip_between;
250 ✗ src_len -= nal_size + skip_between;
251 }
252
253 ✗ if (pass == 0) {
254 /* now we know the total size of the packet (with the
255 * start sequences added) */
256 ✗ if ((ret = av_new_packet(pkt, total_length)) < 0)
257 ✗ return ret;
258 ✗ dst = pkt->data;
259 }
260 }
261
262 ✗ return 0;
263 }
264
265 ✗ int ff_h264_handle_frag_packet(AVPacket *pkt, const uint8_t *buf, int len,
266 int start_bit, const uint8_t *nal_header,
267 int nal_header_len)
268 {
269 int ret;
270 ✗ int tot_len = len;
271 ✗ int pos = 0;
272 ✗ if (start_bit)
273 ✗ tot_len += sizeof(start_sequence) + nal_header_len;
274 ✗ if ((ret = av_new_packet(pkt, tot_len)) < 0)
275 ✗ return ret;
276 ✗ if (start_bit) {
277 ✗ memcpy(pkt->data + pos, start_sequence, sizeof(start_sequence));
278 ✗ pos += sizeof(start_sequence);
279 ✗ memcpy(pkt->data + pos, nal_header, nal_header_len);
280 ✗ pos += nal_header_len;
281 }
282 ✗ memcpy(pkt->data + pos, buf, len);
283 ✗ return 0;
284 }
285
286 ✗ static int h264_handle_packet_fu_a(AVFormatContext *ctx, PayloadContext *data, AVPacket *pkt,
287 const uint8_t *buf, int len,
288 int *nal_counters, int nal_mask)
289 {
290 uint8_t fu_indicator, fu_header, start_bit, nal_type, nal;
291
292 ✗ if (len < 3) {
293 ✗ av_log(ctx, AV_LOG_ERROR, "Too short data for FU-A H.264 RTP packet\n");
294 ✗ return AVERROR_INVALIDDATA;
295 }
296
297 ✗ fu_indicator = buf[0];
298 ✗ fu_header = buf[1];
299 ✗ start_bit = fu_header >> 7;
300 ✗ nal_type = fu_header & 0x1f;
301 ✗ nal = fu_indicator & 0xe0 | nal_type;
302
303 // skip the fu_indicator and fu_header
304 ✗ buf += 2;
305 ✗ len -= 2;
306
307 ✗ if (start_bit && nal_counters)
308 ✗ nal_counters[nal_type & nal_mask]++;
309 ✗ return ff_h264_handle_frag_packet(pkt, buf, len, start_bit, &nal, 1);
310 }
311
312 // return 0 on packet, no more left, 1 on packet, 1 on partial packet
313 ✗ static int h264_handle_packet(AVFormatContext *ctx, PayloadContext *data,
314 AVStream *st, AVPacket *pkt, uint32_t *timestamp,
315 const uint8_t *buf, int len, uint16_t seq,
316 int flags)
317 {
318 uint8_t nal;
319 uint8_t type;
320 ✗ int result = 0;
321
322 ✗ if (!len) {
323 ✗ av_log(ctx, AV_LOG_ERROR, "Empty H.264 RTP packet\n");
324 ✗ return AVERROR_INVALIDDATA;
325 }
326 ✗ nal = buf[0];
327 ✗ type = nal & 0x1f;
328
329 /* Simplify the case (these are all the NAL types used internally by
330 * the H.264 codec). */
331 ✗ if (type >= 1 && type <= 23)
332 ✗ type = 1;
333 ✗ switch (type) {
334 ✗ case 0: // undefined, but pass them through
335 case 1:
336 ✗ if ((result = av_new_packet(pkt, len + sizeof(start_sequence))) < 0)
337 ✗ return result;
338 ✗ memcpy(pkt->data, start_sequence, sizeof(start_sequence));
339 ✗ memcpy(pkt->data + sizeof(start_sequence), buf, len);
340 COUNT_NAL_TYPE(data, nal);
341 ✗ break;
342
343 ✗ case 24: // STAP-A (one packet, multiple nals)
344 // consume the STAP-A NAL
345 ✗ buf++;
346 ✗ len--;
347 ✗ result = ff_h264_handle_aggregated_packet(ctx, data, pkt, buf, len, 0,
348 NAL_COUNTERS, NAL_MASK);
349 ✗ break;
350
351 ✗ case 25: // STAP-B
352 case 26: // MTAP-16
353 case 27: // MTAP-24
354 case 29: // FU-B
355 ✗ avpriv_report_missing_feature(ctx, "RTP H.264 NAL unit type %d", type);
356 ✗ result = AVERROR_PATCHWELCOME;
357 ✗ break;
358
359 ✗ case 28: // FU-A (fragmented nal)
360 ✗ result = h264_handle_packet_fu_a(ctx, data, pkt, buf, len,
361 NAL_COUNTERS, NAL_MASK);
362 ✗ break;
363
364 ✗ case 30: // undefined
365 case 31: // undefined
366 default:
367 ✗ av_log(ctx, AV_LOG_ERROR, "Undefined type (%d)\n", type);
368 ✗ result = AVERROR_INVALIDDATA;
369 ✗ break;
370 }
371
372 ✗ pkt->stream_index = st->index;
373
374 ✗ return result;
375 }
376
377 ✗ static void h264_close_context(PayloadContext *data)
378 {
379 #ifdef DEBUG
380 int ii;
381
382 for (ii = 0; ii < 32; ii++) {
383 if (data->packet_types_received[ii])
384 av_log(NULL, AV_LOG_DEBUG, "Received %d packets of type %d\n",
385 data->packet_types_received[ii], ii);
386 }
387 #endif
388 ✗ }
389
390 ✗ static int parse_h264_sdp_line(AVFormatContext *s, int st_index,
391 PayloadContext *h264_data, const char *line)
392 {
393 AVStream *stream;
394 ✗ const char *p = line;
395
396 ✗ if (st_index < 0)
397 ✗ return 0;
398
399 ✗ stream = s->streams[st_index];
400
401 ✗ if (av_strstart(p, "framesize:", &p)) {
402 ✗ ff_h264_parse_framesize(stream->codecpar, p);
403 ✗ } else if (av_strstart(p, "fmtp:", &p)) {
404 ✗ return ff_parse_fmtp(s, stream, h264_data, p, sdp_parse_fmtp_config_h264);
405 ✗ } else if (av_strstart(p, "cliprect:", &p)) {
406 // could use this if we wanted.
407 }
408
409 ✗ return 0;
410 }
411
412 const RTPDynamicProtocolHandler ff_h264_dynamic_handler = {
413 .enc_name = "H264",
414 .codec_type = AVMEDIA_TYPE_VIDEO,
415 .codec_id = AV_CODEC_ID_H264,
416 .need_parsing = AVSTREAM_PARSE_FULL,
417 .priv_data_size = sizeof(PayloadContext),
418 .parse_sdp_a_line = parse_h264_sdp_line,
419 .close = h264_close_context,
420 .parse_packet = h264_handle_packet,
421 };
422