FFmpeg
vp7dsp_init.c
Go to the documentation of this file.
1 /*
2  * Copyright (c) 2024 Rémi Denis-Courmont.
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 
23 #include "libavutil/attributes.h"
24 #include "libavutil/cpu.h"
25 #include "libavutil/riscv/cpu.h"
26 #include "libavcodec/vp8dsp.h"
27 
28 void ff_vp7_luma_dc_wht_rvv(int16_t block[4][4][16], int16_t dc[16]);
29 void ff_vp7_idct_add_rvv(uint8_t *dst, int16_t block[16], ptrdiff_t stride);
30 void ff_vp78_idct_dc_add_rvv(uint8_t *, int16_t block[16], ptrdiff_t, int dc);
31 void ff_vp7_idct_dc_add4y_rvv(uint8_t *dst, int16_t block[4][16], ptrdiff_t);
32 void ff_vp7_idct_dc_add4uv_rvv(uint8_t *dst, int16_t block[4][16], ptrdiff_t);
33 
34 static void ff_vp7_idct_dc_add_rvv(uint8_t *dst, int16_t block[16],
35  ptrdiff_t stride)
36 {
37  int dc = (23170 * (23170 * block[0] >> 14) + 0x20000) >> 18;
38 
40 }
41 
43 {
44 #if HAVE_RVV
45  int flags = av_get_cpu_flags();
46 
48  ff_rv_vlen_least(128)) {
49 #if __riscv_xlen >= 64
50  c->vp8_luma_dc_wht = ff_vp7_luma_dc_wht_rvv;
51  c->vp8_idct_add = ff_vp7_idct_add_rvv;
52 #endif
53  c->vp8_idct_dc_add = ff_vp7_idct_dc_add_rvv;
54  c->vp8_idct_dc_add4y = ff_vp7_idct_dc_add4y_rvv;
56  c->vp8_idct_dc_add4uv = ff_vp7_idct_dc_add4uv_rvv;
57  }
58 #endif
59 }
ff_vp7_luma_dc_wht_rvv
void ff_vp7_luma_dc_wht_rvv(int16_t block[4][4][16], int16_t dc[16])
av_get_cpu_flags
int av_get_cpu_flags(void)
Return the flags which specify extensions supported by the CPU.
Definition: cpu.c:103
av_cold
#define av_cold
Definition: attributes.h:90
vp8dsp.h
ff_rv_vlen_least
static bool ff_rv_vlen_least(unsigned int bits)
Checks that the vector bit-size is at least the given value.
Definition: cpu.h:65
cpu.h
AV_CPU_FLAG_RVB_ADDR
#define AV_CPU_FLAG_RVB_ADDR
Address bit-manipulations.
Definition: cpu.h:92
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
VP8DSPContext
Definition: vp8dsp.h:37
ff_vp7dsp_init_riscv
av_cold void ff_vp7dsp_init_riscv(VP8DSPContext *c)
Definition: vp7dsp_init.c:42
ff_vp7_idct_add_rvv
void ff_vp7_idct_add_rvv(uint8_t *dst, int16_t block[16], ptrdiff_t stride)
dc
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 top and top right vectors is used as motion vector prediction the used motion vector is the sum of the predictor and(mvx_diff, mvy_diff) *mv_scale Intra DC Prediction block[y][x] dc[1]
Definition: snow.txt:400
cpu.h
attributes.h
AV_CPU_FLAG_RVV_I32
#define AV_CPU_FLAG_RVV_I32
Vectors of 8/16/32-bit int's *‍/.
Definition: cpu.h:87
ff_vp7_idct_dc_add_rvv
static void ff_vp7_idct_dc_add_rvv(uint8_t *dst, int16_t block[16], ptrdiff_t stride)
Definition: vp7dsp_init.c:34
stride
#define stride
Definition: h264pred_template.c:537
ff_vp7_idct_dc_add4uv_rvv
void ff_vp7_idct_dc_add4uv_rvv(uint8_t *dst, int16_t block[4][16], ptrdiff_t)
ff_vp7_idct_dc_add4y_rvv
void ff_vp7_idct_dc_add4y_rvv(uint8_t *dst, int16_t block[4][16], ptrdiff_t)
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:482
block
The exact code depends on how similar the blocks are and how related they are to the block
Definition: filter_design.txt:207
ff_vp78_idct_dc_add_rvv
void ff_vp78_idct_dc_add_rvv(uint8_t *, int16_t block[16], ptrdiff_t, int dc)
AV_CPU_FLAG_RVV_I64
#define AV_CPU_FLAG_RVV_I64
Vectors of 64-bit int's *‍/.
Definition: cpu.h:89