FFmpeg
lossless_videodsp.c
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1 /*
2  * Lossless video DSP utils
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #include "config.h"
22 #include "lossless_videodsp.h"
23 #include "libavcodec/mathops.h"
24 
25 // 0x7f7f7f7f or 0x7f7f7f7f7f7f7f7f or whatever, depending on the cpu's native arithmetic size
26 #define pb_7f (~0UL / 255 * 0x7f)
27 #define pb_80 (~0UL / 255 * 0x80)
28 
29 static void add_bytes_c(uint8_t *dst, uint8_t *src, ptrdiff_t w)
30 {
31  long i;
32 
33  for (i = 0; i <= w - (int) sizeof(long); i += sizeof(long)) {
34  long a = *(long *) (src + i);
35  long b = *(long *) (dst + i);
36  *(long *) (dst + i) = ((a & pb_7f) + (b & pb_7f)) ^ ((a ^ b) & pb_80);
37  }
38  for (; i < w; i++)
39  dst[i + 0] += src[i + 0];
40 }
41 
42 static void add_median_pred_c(uint8_t *dst, const uint8_t *src1,
43  const uint8_t *diff, ptrdiff_t w,
44  int *left, int *left_top)
45 {
46  int i;
47  uint8_t l, lt;
48 
49  l = *left;
50  lt = *left_top;
51 
52  for (i = 0; i < w; i++) {
53  l = mid_pred(l, src1[i], (l + src1[i] - lt) & 0xFF) + diff[i];
54  lt = src1[i];
55  dst[i] = l;
56  }
57 
58  *left = l;
59  *left_top = lt;
60 }
61 
62 static int add_left_pred_c(uint8_t *dst, const uint8_t *src, ptrdiff_t w,
63  int acc)
64 {
65  int i;
66 
67  for (i = 0; i < w - 1; i++) {
68  acc += src[i];
69  dst[i] = acc;
70  i++;
71  acc += src[i];
72  dst[i] = acc;
73  }
74 
75  for (; i < w; i++) {
76  acc += src[i];
77  dst[i] = acc;
78  }
79 
80  return acc;
81 }
82 
83 static int add_left_pred_int16_c(uint16_t *dst, const uint16_t *src, unsigned mask, ptrdiff_t w, unsigned acc){
84  int i;
85 
86  for(i=0; i<w-1; i++){
87  acc+= src[i];
88  dst[i]= acc &= mask;
89  i++;
90  acc+= src[i];
91  dst[i]= acc &= mask;
92  }
93 
94  for(; i<w; i++){
95  acc+= src[i];
96  dst[i]= acc &= mask;
97  }
98 
99  return acc;
100 }
101 
102 static void add_gradient_pred_c(uint8_t *src, const ptrdiff_t stride, const ptrdiff_t width){
103  int A, B, C, i;
104 
105  for (i = 0; i < width; i++) {
106  A = src[i - stride];
107  B = src[i - (stride + 1)];
108  C = src[i - 1];
109  src[i] = (A - B + C + src[i]) & 0xFF;
110  }
111 }
112 
114 {
115  c->add_bytes = add_bytes_c;
116  c->add_median_pred = add_median_pred_c;
117  c->add_left_pred = add_left_pred_c;
118 
119  c->add_left_pred_int16 = add_left_pred_int16_c;
120  c->add_gradient_pred = add_gradient_pred_c;
121 
122 #if ARCH_PPC
124 #elif ARCH_RISCV
126 #elif ARCH_X86
128 #endif
129 }
A
#define A(x)
Definition: vpx_arith.h:28
add_median_pred_c
static void add_median_pred_c(uint8_t *dst, const uint8_t *src1, const uint8_t *diff, ptrdiff_t w, int *left, int *left_top)
Definition: lossless_videodsp.c:42
acc
int acc
Definition: yuv2rgb.c:554
src1
const pixel * src1
Definition: h264pred_template.c:421
add_left_pred_c
static int add_left_pred_c(uint8_t *dst, const uint8_t *src, ptrdiff_t w, int acc)
Definition: lossless_videodsp.c:62
w
uint8_t w
Definition: llviddspenc.c:38
add_left_pred_int16_c
static int add_left_pred_int16_c(uint16_t *dst, const uint16_t *src, unsigned mask, ptrdiff_t w, unsigned acc)
Definition: lossless_videodsp.c:83
b
#define b
Definition: input.c:41
ff_llviddsp_init_x86
void ff_llviddsp_init_x86(LLVidDSPContext *llviddsp)
Definition: lossless_videodsp_init.c:45
add_gradient_pred_c
static void add_gradient_pred_c(uint8_t *src, const ptrdiff_t stride, const ptrdiff_t width)
Definition: lossless_videodsp.c:102
LLVidDSPContext
Definition: lossless_videodsp.h:28
pb_80
#define pb_80
Definition: lossless_videodsp.c:27
C
s EdgeDetect Foobar g libavfilter vf_edgedetect c libavfilter vf_foobar c edit libavfilter and add an entry for foobar following the pattern of the other filters edit libavfilter allfilters and add an entry for foobar following the pattern of the other filters configure make j< whatever > ffmpeg ffmpeg i you should get a foobar png with Lena edge detected That s your new playground is ready Some little details about what s going which in turn will define variables for the build system and the C
Definition: writing_filters.txt:58
mask
static const uint16_t mask[17]
Definition: lzw.c:38
width
#define width
B
#define B
Definition: huffyuv.h:42
mathops.h
ff_llviddsp_init_riscv
void ff_llviddsp_init_riscv(LLVidDSPContext *llviddsp)
Definition: llviddsp_init.c:29
c
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
ff_llviddsp_init_ppc
void ff_llviddsp_init_ppc(LLVidDSPContext *llviddsp)
Definition: lossless_videodsp_altivec.c:51
diff
static av_always_inline int diff(const struct color_info *a, const struct color_info *b, const int trans_thresh)
Definition: vf_paletteuse.c:164
a
The reader does not expect b to be semantically here and if the code is changed by maybe adding a a division or other the signedness will almost certainly be mistaken To avoid this confusion a new type was SUINT is the C unsigned type but it holds a signed int to use the same example SUINT a
Definition: undefined.txt:41
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:255
add_bytes_c
static void add_bytes_c(uint8_t *dst, uint8_t *src, ptrdiff_t w)
Definition: lossless_videodsp.c:29
stride
#define stride
Definition: h264pred_template.c:537
mid_pred
#define mid_pred
Definition: mathops.h:98
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
ff_llviddsp_init
void ff_llviddsp_init(LLVidDSPContext *c)
Definition: lossless_videodsp.c:113
lossless_videodsp.h
pb_7f
#define pb_7f
Definition: lossless_videodsp.c:26
src
INIT_CLIP pixel * src
Definition: h264pred_template.c:418
int
int
Definition: ffmpeg_filter.c:425