FFmpeg
rtpenc_rfc4175.c
Go to the documentation of this file.
1 /*
2  * RTP Packetization of RAW video (RFC4175)
3  * Copyright (c) 2021 Limin Wang
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 #include "avformat.h"
22 #include "rtpenc.h"
23 
24 void ff_rtp_send_raw_rfc4175(AVFormatContext *s1, const uint8_t *buf, int size, int interlaced, int field)
25 {
26  RTPMuxContext *s = s1->priv_data;
27  int width = s1->streams[0]->codecpar->width;
28  int height = s1->streams[0]->codecpar->height;
29  int xinc, yinc, pgroup;
30  int i = 0;
31  int offset = 0;
32 
33  s->timestamp = s->cur_timestamp;
34  switch (s1->streams[0]->codecpar->format) {
35  case AV_PIX_FMT_UYVY422:
36  xinc = 2;
37  yinc = 1 << interlaced;
38  pgroup = 4;
39  break;
41  xinc = 2;
42  yinc = 1 << interlaced;
43  pgroup = 5;
44  break;
45  case AV_PIX_FMT_YUV420P:
46  xinc = 4;
47  yinc = 1 << interlaced;
48  pgroup = 6;
49  break;
50  case AV_PIX_FMT_RGB24:
51  xinc = 1;
52  yinc = 1 << interlaced;
53  pgroup = 3;
54  break;
55  case AV_PIX_FMT_BGR24:
56  xinc = 1;
57  yinc = 1 << interlaced;
58  pgroup = 3;
59  break;
60  default:
61  return;
62  }
63 
64  while (i < height) {
65  int left = s->max_payload_size;
66  uint8_t *dest = s->buf;
67  uint8_t *headers;
68  const int head_size = 6;
69  int next_line;
70  int length, cont, pixels;
71 
72  /* Extended Sequence Number */
73  *dest++ = 0;
74  *dest++ = 0;
75  left -= 2;
76 
77  headers = dest;
78  do {
79  int l_line;
80 
81  pixels = width - offset;
82  length = (pixels * pgroup) / xinc;
83 
84  left -= head_size;
85  if (left >= length) {
86  next_line = 1;
87  } else {
88  pixels = (left / pgroup) * xinc;
89  length = (pixels * pgroup) / xinc;
90  next_line = 0;
91  }
92  left -= length;
93 
94  /* Length */
95  *dest++ = (length >> 8) & 0xff;
96  *dest++ = length & 0xff;
97 
98  /* Line No */
99  l_line = i >> interlaced;
100  *dest++ = ((l_line >> 8) & 0x7f) | ((field << 7) & 0x80);
101  *dest++ = l_line & 0xff;
102  if (next_line) i += yinc;
103 
104  cont = (left > (head_size + pgroup) && i < height) ? 0x80 : 0x00;
105  /* Offset and Continuation marker */
106  *dest++ = ((offset >> 8) & 0x7f) | cont;
107  *dest++ = offset & 0xff;
108 
109  if (next_line)
110  offset = 0;
111  else
112  offset += pixels;
113  } while (cont);
114 
115  do {
116  int l_field;
117  int l_line;
118  int l_off;
119  int copy_offset;
120 
121  length = (headers[0] << 8) | headers[1];
122  l_field = (headers[2] & 0x80) >> 7;
123  l_line = ((headers[2] & 0x7f) << 8) | headers[3];
124  l_off = ((headers[4] & 0x7f) << 8) | headers[5];
125  cont = headers[4] & 0x80;
126  headers += head_size;
127 
128  if (interlaced)
129  l_line = 2 * l_line + l_field;
130  copy_offset = (l_line * width + l_off) * pgroup / xinc;
131  if (copy_offset + length > size)
132  break;
133  memcpy (dest, buf + copy_offset, length);
134  dest += length;
135  } while (cont);
136 
137  ff_rtp_send_data (s1, s->buf, s->max_payload_size - left, i >= height);
138  }
139 }
ff_rtp_send_data
void ff_rtp_send_data(AVFormatContext *s1, const uint8_t *buf1, int len, int m)
Definition: rtpenc.c:334
AV_PIX_FMT_BGR24
@ AV_PIX_FMT_BGR24
packed RGB 8:8:8, 24bpp, BGRBGR...
Definition: pixfmt.h:69
width
#define width
s
#define s(width, name)
Definition: cbs_vp9.c:256
s1
#define s1
Definition: regdef.h:38
field
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 field
Definition: writing_filters.txt:78
AV_PIX_FMT_YUV420P
@ AV_PIX_FMT_YUV420P
planar YUV 4:2:0, 12bpp, (1 Cr & Cb sample per 2x2 Y samples)
Definition: pixfmt.h:66
AVFormatContext
Format I/O context.
Definition: avformat.h:1216
RTPMuxContext
Definition: rtpenc.h:27
AV_PIX_FMT_YUV422P10
#define AV_PIX_FMT_YUV422P10
Definition: pixfmt.h:460
AV_PIX_FMT_RGB24
@ AV_PIX_FMT_RGB24
packed RGB 8:8:8, 24bpp, RGBRGB...
Definition: pixfmt.h:68
size
int size
Definition: twinvq_data.h:10344
height
#define height
offset
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 offset
Definition: writing_filters.txt:86
interlaced
uint8_t interlaced
Definition: mxfenc.c:2043
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:269
rtpenc.h
ff_rtp_send_raw_rfc4175
void ff_rtp_send_raw_rfc4175(AVFormatContext *s1, const uint8_t *buf, int size, int interlaced, int field)
Definition: rtpenc_rfc4175.c:24
avformat.h
left
Tag MUST be and< 10hcoeff half pel interpolation filter coefficients, hcoeff[0] are the 2 middle coefficients[1] are the next outer ones and so on, resulting in a filter like:...eff[2], hcoeff[1], hcoeff[0], hcoeff[0], hcoeff[1], hcoeff[2] ... the sign of the coefficients is not explicitly stored but alternates after each coeff and coeff[0] is positive, so ...,+,-,+,-,+,+,-,+,-,+,... hcoeff[0] is not explicitly stored but found by subtracting the sum of all stored coefficients with signs from 32 hcoeff[0]=32 - hcoeff[1] - hcoeff[2] - ... a good choice for hcoeff and htaps is htaps=6 hcoeff={40,-10, 2} an alternative which requires more computations at both encoder and decoder side and may or may not be better is htaps=8 hcoeff={42,-14, 6,-2}ref_frames minimum of the number of available reference frames and max_ref_frames for example the first frame after a key frame always has ref_frames=1spatial_decomposition_type wavelet type 0 is a 9/7 symmetric compact integer wavelet 1 is a 5/3 symmetric compact integer wavelet others are reserved stored as delta from last, last is reset to 0 if always_reset||keyframeqlog quality(logarithmic quantizer scale) stored as delta from last, last is reset to 0 if always_reset||keyframemv_scale stored as delta from last, last is reset to 0 if always_reset||keyframe FIXME check that everything works fine if this changes between framesqbias dequantization bias stored as delta from last, last is reset to 0 if always_reset||keyframeblock_max_depth maximum depth of the block tree stored as delta from last, last is reset to 0 if always_reset||keyframequant_table quantization tableHighlevel bitstream structure:==============================--------------------------------------------|Header|--------------------------------------------|------------------------------------|||Block0||||split?||||yes no||||......... intra?||||:Block01 :yes no||||:Block02 :....... ..........||||:Block03 ::y DC ::ref index:||||:Block04 ::cb DC ::motion x :||||......... :cr DC ::motion y :||||....... ..........|||------------------------------------||------------------------------------|||Block1|||...|--------------------------------------------|------------ ------------ ------------|||Y subbands||Cb subbands||Cr subbands||||--- ---||--- ---||--- ---|||||LL0||HL0||||LL0||HL0||||LL0||HL0|||||--- ---||--- ---||--- ---||||--- ---||--- ---||--- ---|||||LH0||HH0||||LH0||HH0||||LH0||HH0|||||--- ---||--- ---||--- ---||||--- ---||--- ---||--- ---|||||HL1||LH1||||HL1||LH1||||HL1||LH1|||||--- ---||--- ---||--- ---||||--- ---||--- ---||--- ---|||||HH1||HL2||||HH1||HL2||||HH1||HL2|||||...||...||...|||------------ ------------ ------------|--------------------------------------------Decoding process:=================------------|||Subbands|------------||||------------|Intra DC||||LL0 subband prediction ------------|\ Dequantization ------------------- \||Reference frames|\ IDWT|------- -------|Motion \|||Frame 0||Frame 1||Compensation . OBMC v -------|------- -------|--------------. \------> Frame n output Frame Frame<----------------------------------/|...|------------------- Range Coder:============Binary Range Coder:------------------- The implemented range coder is an adapted version based upon "Range encoding: an algorithm for removing redundancy from a digitised message." by G. N. N. Martin. The symbols encoded by the Snow range coder are bits(0|1). The associated probabilities are not fix but change depending on the symbol mix seen so far. bit seen|new state ---------+----------------------------------------------- 0|256 - state_transition_table[256 - old_state];1|state_transition_table[old_state];state_transition_table={ 0, 0, 0, 0, 0, 0, 0, 0, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 190, 191, 192, 194, 194, 195, 196, 197, 198, 199, 200, 201, 202, 202, 204, 205, 206, 207, 208, 209, 209, 210, 211, 212, 213, 215, 215, 216, 217, 218, 219, 220, 220, 222, 223, 224, 225, 226, 227, 227, 229, 229, 230, 231, 232, 234, 234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, 246, 247, 248, 248, 0, 0, 0, 0, 0, 0, 0};FIXME Range Coding of integers:------------------------- FIXME Neighboring Blocks:===================left and top are set to the respective blocks unless they are outside of the image in which case they are set to the Null block top-left is set to the top left block unless it is outside of the image in which case it is set to the left block if this block has no larger parent block or it is at the left side of its parent block and the top right block is not outside of the image then the top right block is used for top-right else the top-left block is used Null block y, cb, cr are 128 level, ref, mx and my are 0 Motion Vector Prediction:=========================1. the motion vectors of all the neighboring blocks are scaled to compensate for the difference of reference frames scaled_mv=(mv *(256 *(current_reference+1)/(mv.reference+1))+128)> the median of the scaled left
Definition: snow.txt:386
AV_PIX_FMT_UYVY422
@ AV_PIX_FMT_UYVY422
packed YUV 4:2:2, 16bpp, Cb Y0 Cr Y1
Definition: pixfmt.h:81
headers
FFmpeg currently uses a custom build this text attempts to document some of its obscure features and options Makefile the full command issued by make and its output will be shown on the screen DBG Preprocess x86 external assembler files to a dbg asm file in the object which then gets compiled Helps in developing those assembler files DESTDIR Destination directory for the install useful to prepare packages or install FFmpeg in cross environments GEN Set to ‘1’ to generate the missing or mismatched references Makefile builds all the libraries and the executables fate Run the fate test note that you must have installed it fate list List all fate regression test targets install Install headers
Definition: build_system.txt:34