FFmpeg
rtpenc_h264_hevc.c
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1 /*
2  * RTP packetization for H.264 (RFC3984)
3  * RTP packetizer for HEVC/H.265 payload format (draft version 6)
4  * Copyright (c) 2008 Luca Abeni
5  * Copyright (c) 2014 Thomas Volkert <thomas@homer-conferencing.com>
6  *
7  * This file is part of FFmpeg.
8  *
9  * FFmpeg is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU Lesser General Public
11  * License as published by the Free Software Foundation; either
12  * version 2.1 of the License, or (at your option) any later version.
13  *
14  * FFmpeg is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17  * Lesser General Public License for more details.
18  *
19  * You should have received a copy of the GNU Lesser General Public
20  * License along with FFmpeg; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22  */
23 
24 /**
25  * @file
26  * @brief H.264/HEVC packetization
27  * @author Luca Abeni <lucabe72@email.it>
28  */
29 
30 #include "libavutil/intreadwrite.h"
31 
32 #include "avformat.h"
33 #include "avc.h"
34 #include "rtpenc.h"
35 
36 static void flush_buffered(AVFormatContext *s1, int last)
37 {
38  RTPMuxContext *s = s1->priv_data;
39  if (s->buf_ptr != s->buf) {
40  // If we're only sending one single NAL unit, send it as such, skip
41  // the STAP-A/AP framing
42  if (s->buffered_nals == 1) {
43  enum AVCodecID codec = s1->streams[0]->codecpar->codec_id;
44  if (codec == AV_CODEC_ID_H264)
45  ff_rtp_send_data(s1, s->buf + 3, s->buf_ptr - s->buf - 3, last);
46  else
47  ff_rtp_send_data(s1, s->buf + 4, s->buf_ptr - s->buf - 4, last);
48  } else
49  ff_rtp_send_data(s1, s->buf, s->buf_ptr - s->buf, last);
50  }
51  s->buf_ptr = s->buf;
52  s->buffered_nals = 0;
53 }
54 
55 static void nal_send(AVFormatContext *s1, const uint8_t *buf, int size, int last)
56 {
57  RTPMuxContext *s = s1->priv_data;
58  enum AVCodecID codec = s1->streams[0]->codecpar->codec_id;
59 
60  av_log(s1, AV_LOG_DEBUG, "Sending NAL %x of len %d M=%d\n", buf[0] & 0x1F, size, last);
61  if (size <= s->max_payload_size) {
62  int buffered_size = s->buf_ptr - s->buf;
63  int header_size;
64  int skip_aggregate = 0;
65 
66  if (codec == AV_CODEC_ID_H264) {
67  header_size = 1;
68  skip_aggregate = s->flags & FF_RTP_FLAG_H264_MODE0;
69  } else {
70  header_size = 2;
71  }
72 
73  // Flush buffered NAL units if the current unit doesn't fit
74  if (buffered_size + 2 + size > s->max_payload_size) {
75  flush_buffered(s1, 0);
76  buffered_size = 0;
77  }
78  // If we aren't using mode 0, and the NAL unit fits including the
79  // framing (2 bytes length, plus 1/2 bytes for the STAP-A/AP marker),
80  // write the unit to the buffer as a STAP-A/AP packet, otherwise flush
81  // and send as single NAL.
82  if (buffered_size + 2 + header_size + size <= s->max_payload_size &&
83  !skip_aggregate) {
84  if (buffered_size == 0) {
85  if (codec == AV_CODEC_ID_H264) {
86  *s->buf_ptr++ = 24;
87  } else {
88  *s->buf_ptr++ = 48 << 1;
89  *s->buf_ptr++ = 1;
90  }
91  }
92  AV_WB16(s->buf_ptr, size);
93  s->buf_ptr += 2;
94  memcpy(s->buf_ptr, buf, size);
95  s->buf_ptr += size;
96  s->buffered_nals++;
97  } else {
98  flush_buffered(s1, 0);
99  ff_rtp_send_data(s1, buf, size, last);
100  }
101  } else {
102  int flag_byte, header_size;
103  flush_buffered(s1, 0);
104  if (codec == AV_CODEC_ID_H264 && (s->flags & FF_RTP_FLAG_H264_MODE0)) {
105  av_log(s1, AV_LOG_ERROR,
106  "NAL size %d > %d, try -slice-max-size %d\n", size,
108  return;
109  }
110  av_log(s1, AV_LOG_DEBUG, "NAL size %d > %d\n", size, s->max_payload_size);
111  if (codec == AV_CODEC_ID_H264) {
112  uint8_t type = buf[0] & 0x1F;
113  uint8_t nri = buf[0] & 0x60;
114 
115  s->buf[0] = 28; /* FU Indicator; Type = 28 ---> FU-A */
116  s->buf[0] |= nri;
117  s->buf[1] = type;
118  s->buf[1] |= 1 << 7;
119  buf += 1;
120  size -= 1;
121 
122  flag_byte = 1;
123  header_size = 2;
124  } else {
125  uint8_t nal_type = (buf[0] >> 1) & 0x3F;
126  /*
127  * create the HEVC payload header and transmit the buffer as fragmentation units (FU)
128  *
129  * 0 1
130  * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
131  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
132  * |F| Type | LayerId | TID |
133  * +-------------+-----------------+
134  *
135  * F = 0
136  * Type = 49 (fragmentation unit (FU))
137  * LayerId = 0
138  * TID = 1
139  */
140  s->buf[0] = 49 << 1;
141  s->buf[1] = 1;
142 
143  /*
144  * create the FU header
145  *
146  * 0 1 2 3 4 5 6 7
147  * +-+-+-+-+-+-+-+-+
148  * |S|E| FuType |
149  * +---------------+
150  *
151  * S = variable
152  * E = variable
153  * FuType = NAL unit type
154  */
155  s->buf[2] = nal_type;
156  /* set the S bit: mark as start fragment */
157  s->buf[2] |= 1 << 7;
158 
159  /* pass the original NAL header */
160  buf += 2;
161  size -= 2;
162 
163  flag_byte = 2;
164  header_size = 3;
165  }
166 
167  while (size + header_size > s->max_payload_size) {
168  memcpy(&s->buf[header_size], buf, s->max_payload_size - header_size);
169  ff_rtp_send_data(s1, s->buf, s->max_payload_size, 0);
170  buf += s->max_payload_size - header_size;
171  size -= s->max_payload_size - header_size;
172  s->buf[flag_byte] &= ~(1 << 7);
173  }
174  s->buf[flag_byte] |= 1 << 6;
175  memcpy(&s->buf[header_size], buf, size);
176  ff_rtp_send_data(s1, s->buf, size + header_size, last);
177  }
178 }
179 
181 {
182  const uint8_t *r, *end = buf1 + size;
183  RTPMuxContext *s = s1->priv_data;
184 
185  s->timestamp = s->cur_timestamp;
186  s->buf_ptr = s->buf;
187  if (s->nal_length_size)
188  r = ff_avc_mp4_find_startcode(buf1, end, s->nal_length_size) ? buf1 : end;
189  else
190  r = ff_avc_find_startcode(buf1, end);
191  while (r < end) {
192  const uint8_t *r1;
193 
194  if (s->nal_length_size) {
196  if (!r1)
197  r1 = end;
198  r += s->nal_length_size;
199  } else {
200  while (!*(r++));
201  r1 = ff_avc_find_startcode(r, end);
202  }
203  nal_send(s1, r, r1 - r, r1 == end);
204  r = r1;
205  }
206  flush_buffered(s1, 1);
207 }
const uint8_t * ff_avc_find_startcode(const uint8_t *p, const uint8_t *end)
Definition: avc.c:67
static void nal_send(AVFormatContext *s1, const uint8_t *buf, int size, int last)
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3970
GLint GLenum type
Definition: opengl_enc.c:104
int max_payload_size
Definition: rtpenc.h:38
int nal_length_size
Number of bytes used for H.264 NAL length, if the MP4 syntax is used (1, 2 or 4)
Definition: rtpenc.h:58
Format I/O context.
Definition: avformat.h:1358
uint8_t
static av_cold int end(AVCodecContext *avctx)
Definition: avrndec.c:90
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1426
static void flush_buffered(AVFormatContext *s1, int last)
uint8_t * buf
Definition: rtpenc.h:49
ptrdiff_t size
Definition: opengl_enc.c:100
#define AV_WB16(p, v)
Definition: intreadwrite.h:405
#define av_log(a,...)
AVCodecID
Identify the syntax and semantics of the bitstream.
Definition: avcodec.h:215
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
const char * r
Definition: vf_curves.c:114
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:197
#define FF_RTP_FLAG_H264_MODE0
Definition: rtpenc.h:71
void ff_rtp_send_data(AVFormatContext *s1, const uint8_t *buf1, int len, int m)
Definition: rtpenc.c:332
#define s(width, name)
Definition: cbs_vp9.c:257
uint32_t cur_timestamp
Definition: rtpenc.h:37
void * buf
Definition: avisynth_c.h:766
void ff_rtp_send_h264_hevc(AVFormatContext *s1, const uint8_t *buf1, int size)
int buffered_nals
Definition: rtpenc.h:59
int flags
Definition: rtpenc.h:61
const uint8_t * ff_avc_mp4_find_startcode(const uint8_t *start, const uint8_t *end, int nal_length_size)
Definition: avc.c:254
#define s1
Definition: regdef.h:38
uint8_t * buf_ptr
Definition: rtpenc.h:50
Main libavformat public API header.
uint32_t timestamp
Definition: rtpenc.h:35
void * priv_data
Format private data.
Definition: avformat.h:1386
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1028