FFmpeg: libavformat/rtpenc_h264_hevc.c Source File

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 "nal.h"
35 #include "rtpenc.h"
36 
37  static void flush_buffered(AVFormatContext *s1, int last)
38 {
39  RTPMuxContext *s = s1->priv_data;
40  if (s->buf_ptr != s->buf) {
41  // If we're only sending one single NAL unit, send it as such, skip
42  // the STAP-A/AP framing
43  if (s->buffered_nals == 1) {
44  enum AVCodecID codec = s1->streams[0]->codecpar->codec_id;
45  if (codec == AV_CODEC_ID_H264)
46  ff_rtp_send_data(s1, s->buf + 3, s->buf_ptr - s->buf - 3, last);
47  else
48  ff_rtp_send_data(s1, s->buf + 4, s->buf_ptr - s->buf - 4, last);
49  } else
50  ff_rtp_send_data(s1, s->buf, s->buf_ptr - s->buf, last);
51  }
52  s->buf_ptr = s->buf;
53  s->buffered_nals = 0;
54 }
55 
56  static void nal_send(AVFormatContext *s1, const uint8_t *buf, int size, int last)
57 {
58  RTPMuxContext *s = s1->priv_data;
59  enum AVCodecID codec = s1->streams[0]->codecpar->codec_id;
60 
61  av_log(s1, AV_LOG_DEBUG, "Sending NAL %x of len %d M=%d\n", buf[0] & 0x1F, size, last);
62  if (size <= s->max_payload_size) {
63  int buffered_size = s->buf_ptr - s->buf;
64  int header_size;
65  int skip_aggregate = 0;
66 
67  if (codec == AV_CODEC_ID_H264) {
68  header_size = 1;
69  skip_aggregate = s->flags & FF_RTP_FLAG_H264_MODE0;
70  } else {
71  header_size = 2;
72  }
73 
74  // Flush buffered NAL units if the current unit doesn't fit
75  if (buffered_size + 2 + size > s->max_payload_size) {
76  flush_buffered(s1, 0);
77  buffered_size = 0;
78  }
79  // If we aren't using mode 0, and the NAL unit fits including the
80  // framing (2 bytes length, plus 1/2 bytes for the STAP-A/AP marker),
81  // write the unit to the buffer as a STAP-A/AP packet, otherwise flush
82  // and send as single NAL.
83  if (buffered_size + 2 + header_size + size <= s->max_payload_size &&
84  !skip_aggregate) {
85  if (buffered_size == 0) {
86  if (codec == AV_CODEC_ID_H264) {
87  *s->buf_ptr++ = 24;
88  } else {
89  *s->buf_ptr++ = 48 << 1;
90  *s->buf_ptr++ = 1;
91  }
92  }
93  AV_WB16(s->buf_ptr, size);
94  s->buf_ptr += 2;
95  memcpy(s->buf_ptr, buf, size);
96  s->buf_ptr += size;
97  s->buffered_nals++;
98  } else {
99  flush_buffered(s1, 0);
100  ff_rtp_send_data(s1, buf, size, last);
101  }
102  } else {
103  int flag_byte, header_size;
104  flush_buffered(s1, 0);
105  if (codec == AV_CODEC_ID_H264 && (s->flags & FF_RTP_FLAG_H264_MODE0)) {
106  av_log(s1, AV_LOG_ERROR,
107  "NAL size %d > %d, try -slice-max-size %d\n", size,
108  s->max_payload_size, s->max_payload_size);
109  return;
110  }
111  av_log(s1, AV_LOG_DEBUG, "NAL size %d > %d\n", size, s->max_payload_size);
112  if (codec == AV_CODEC_ID_H264) {
113  uint8_t type = buf[0] & 0x1F;
114  uint8_t nri = buf[0] & 0x60;
115 
116  s->buf[0] = 28; /* FU Indicator; Type = 28 ---> FU-A */
117  s->buf[0] |= nri;
118  s->buf[1] = type;
119  s->buf[1] |= 1 << 7;
120  buf += 1;
121  size -= 1;
122 
123  flag_byte = 1;
124  header_size = 2;
125  } else {
126  uint8_t nal_type = (buf[0] >> 1) & 0x3F;
127  /*
128  * create the HEVC payload header and transmit the buffer as fragmentation units (FU)
129  *
130  * 0 1
131  * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
132  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
133  * |F| Type | LayerId | TID |
134  * +-------------+-----------------+
135  *
136  * F = 0
137  * Type = 49 (fragmentation unit (FU))
138  * LayerId = 0
139  * TID = 1
140  */
141  s->buf[0] = 49 << 1;
142  s->buf[1] = 1;
143 
144  /*
145  * create the FU header
146  *
147  * 0 1 2 3 4 5 6 7
148  * +-+-+-+-+-+-+-+-+
149  * |S|E| FuType |
150  * +---------------+
151  *
152  * S = variable
153  * E = variable
154  * FuType = NAL unit type
155  */
156  s->buf[2] = nal_type;
157  /* set the S bit: mark as start fragment */
158  s->buf[2] |= 1 << 7;
159 
160  /* pass the original NAL header */
161  buf += 2;
162  size -= 2;
163 
164  flag_byte = 2;
165  header_size = 3;
166  }
167 
168  while (size + header_size > s->max_payload_size) {
169  memcpy(&s->buf[header_size], buf, s->max_payload_size - header_size);
170  ff_rtp_send_data(s1, s->buf, s->max_payload_size, 0);
171  buf += s->max_payload_size - header_size;
172  size -= s->max_payload_size - header_size;
173  s->buf[flag_byte] &= ~(1 << 7);
174  }
175  s->buf[flag_byte] |= 1 << 6;
176  memcpy(&s->buf[header_size], buf, size);
177  ff_rtp_send_data(s1, s->buf, size + header_size, last);
178  }
179 }
180 
181  void ff_rtp_send_h264_hevc(AVFormatContext *s1, const uint8_t *buf1, int size)
182 {
183  const uint8_t *r, *end = buf1 + size;
184  RTPMuxContext *s = s1->priv_data;
185 
186  s->timestamp = s->cur_timestamp;
187  s->buf_ptr = s->buf;
188  if (s->nal_length_size)
189  r = ff_nal_mp4_find_startcode(buf1, end, s->nal_length_size) ? buf1 : end;
190  else
191  r = ff_nal_find_startcode(buf1, end);
192  while (r < end) {
193  const uint8_t *r1;
194 
195  if (s->nal_length_size) {
196  r1 = ff_nal_mp4_find_startcode(r, end, s->nal_length_size);
197  if (!r1)
198  r1 = end;
199  // Check that the last is not truncated
200  if (r1 - r < s->nal_length_size)
201  break;
202  r += s->nal_length_size;
203  } else {
204  while (!*(r++));
205  r1 = ff_nal_find_startcode(r, end);
206  }
207  nal_send(s1, r, r1 - r, r1 == end);
208  r = r1;
209  }
210  flush_buffered(s1, 1);
211 }
r
const char * r
Definition: vf_curves.c:127
ff_rtp_send_h264_hevc
void ff_rtp_send_h264_hevc(AVFormatContext *s1, const uint8_t *buf1, int size)
Definition: rtpenc_h264_hevc.c:181
AVFormatContext::streams
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1332
ff_rtp_send_data
void ff_rtp_send_data(AVFormatContext *s1, const uint8_t *buf1, int len, int m)
Definition: rtpenc.c:356
FF_RTP_FLAG_H264_MODE0
#define FF_RTP_FLAG_H264_MODE0
Definition: rtpenc.h:71
type
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf type
Definition: writing_filters.txt:86
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:210
ff_nal_mp4_find_startcode
const uint8_t * ff_nal_mp4_find_startcode(const uint8_t *start, const uint8_t *end, int nal_length_size)
Definition: nal.c:143
intreadwrite.h
s
#define s(width, name)
Definition: cbs_vp9.c:198
AV_LOG_DEBUG
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:231
AV_CODEC_ID_H264
@ AV_CODEC_ID_H264
Definition: codec_id.h:79
AVFormatContext
Format I/O context.
Definition: avformat.h:1264
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:767
AV_WB16
#define AV_WB16(p, v)
Definition: intreadwrite.h:401
avc.h
RTPMuxContext
Definition: rtpenc.h:27
AVCodecID
AVCodecID
Identify the syntax and semantics of the bitstream.
Definition: codec_id.h:49
nal_send
static void nal_send(AVFormatContext *s1, const uint8_t *buf, int size, int last)
Definition: rtpenc_h264_hevc.c:56
size
int size
Definition: twinvq_data.h:10344
rtpenc.h
nal.h
flush_buffered
static void flush_buffered(AVFormatContext *s1, int last)
Definition: rtpenc_h264_hevc.c:37
avformat.h
AVCodecParameters::codec_id
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:55
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:27
ff_nal_find_startcode
const uint8_t * ff_nal_find_startcode(const uint8_t *p, const uint8_t *end)
Definition: nal.c:68
AVFormatContext::priv_data
void * priv_data
Format private data.
Definition: avformat.h:1292
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