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   28 #define POS(x, y) src[(x) + stride * (y)] 
   33                                               int log2_size, 
int c_idx)
 
   36     ((x) >> sps->log2_min_pu_size) 
   38     (s->cur_frame->tab_mvf[(x) + (y) * min_pu_width]) 
   39 #define MVF_PU(x, y) \ 
   40     MVF(PU(x0 + ((x) * (1 << hshift))), PU(y0 + ((y) * (1 << vshift)))) 
   41 #define IS_INTRA(x, y) \ 
   42     (MVF_PU(x, y).pred_flag == PF_INTRA) 
   43 #define MIN_TB_ADDR_ZS(x, y) \ 
   44     pps->min_tb_addr_zs[(y) * (sps->tb_mask+2) + (x)] 
   45 #define EXTEND(ptr, val, len)         \ 
   47     pixel4 pix = PIXEL_SPLAT_X4(val); \ 
   48     for (i = 0; i < (len); i += 4)    \ 
   49         AV_WN4P(ptr + i, pix);        \ 
   52 #define EXTEND_RIGHT_CIP(ptr, start, length)                                   \ 
   53         for (i = start; i < (start) + (length); i += 4)                        \ 
   54             if (!IS_INTRA(i, -1))                                              \ 
   55                 AV_WN4P(&ptr[i], a);                                           \ 
   57                 a = PIXEL_SPLAT_X4(ptr[i+3]) 
   58 #define EXTEND_LEFT_CIP(ptr, start, length) \ 
   59         for (i = start; i > (start) - (length); i--) \ 
   60             if (!IS_INTRA(i - 1, -1)) \ 
   62 #define EXTEND_UP_CIP(ptr, start, length)                                      \ 
   63         for (i = (start); i > (start) - (length); i -= 4)                      \ 
   64             if (!IS_INTRA(-1, i - 3))                                          \ 
   65                 AV_WN4P(&ptr[i - 3], a);                                       \ 
   67                 a = PIXEL_SPLAT_X4(ptr[i - 3]) 
   68 #define EXTEND_DOWN_CIP(ptr, start, length)                                    \ 
   69         for (i = start; i < (start) + (length); i += 4)                        \ 
   70             if (!IS_INTRA(-1, i))                                              \ 
   71                 AV_WN4P(&ptr[i], a);                                           \ 
   73                 a = PIXEL_SPLAT_X4(ptr[i + 3]) 
   78     int hshift = 
sps->hshift[c_idx];
 
   79     int vshift = 
sps->vshift[c_idx];
 
   80     int size = (1 << log2_size);
 
   81     int size_in_luma_h = 
size << hshift;
 
   82     int size_in_tbs_h  = size_in_luma_h >> 
sps->log2_min_tb_size;
 
   83     int size_in_luma_v = 
size << vshift;
 
   84     int size_in_tbs_v  = size_in_luma_v >> 
sps->log2_min_tb_size;
 
   87     int x_tb = (x0 >> 
sps->log2_min_tb_size) & 
sps->tb_mask;
 
   88     int y_tb = (y0 >> 
sps->log2_min_tb_size) & 
sps->tb_mask;
 
   89     int spin = c_idx && !size_in_tbs_v && ((2 * y0) & (1 << 
sps->log2_min_tb_size));
 
   93     ptrdiff_t 
stride = 
s->cur_frame->f->linesize[c_idx] / 
sizeof(
pixel);
 
   96     int min_pu_width = 
sps->min_pu_width;
 
   99                               lc->tu.intra_pred_mode;
 
  107     pixel  *top           = top_array  + 1;
 
  108     pixel  *filtered_left = filtered_left_array + 1;
 
  109     pixel  *filtered_top  = filtered_top_array  + 1;
 
  110     int cand_bottom_left = lc->na.cand_bottom_left && cur_tb_addr > 
MIN_TB_ADDR_ZS( x_tb - 1, (y_tb + size_in_tbs_v + spin) & 
sps->tb_mask);
 
  111     int cand_left        = lc->na.cand_left;
 
  112     int cand_up_left     = lc->na.cand_up_left;
 
  113     int cand_up          = lc->na.cand_up;
 
  114     int cand_up_right    = lc->na.cand_up_right && !spin && cur_tb_addr > 
MIN_TB_ADDR_ZS((x_tb + size_in_tbs_h) & 
sps->tb_mask, y_tb - 1);
 
  116     int bottom_left_size = (
FFMIN(y0 + 2 * size_in_luma_v, 
sps->height) -
 
  117                            (y0 + size_in_luma_v)) >> vshift;
 
  118     int top_right_size   = (
FFMIN(x0 + 2 * size_in_luma_h, 
sps->width) -
 
  119                            (x0 + size_in_luma_h)) >> hshift;
 
  121     if (
pps->constrained_intra_pred_flag == 1) {
 
  122         int size_in_luma_pu_v = 
PU(size_in_luma_v);
 
  123         int size_in_luma_pu_h = 
PU(size_in_luma_h);
 
  126         if (!size_in_luma_pu_h)
 
  128         if (cand_bottom_left == 1 && on_pu_edge_x) {
 
  129             int x_left_pu   = 
PU(x0 - 1);
 
  130             int y_bottom_pu = 
PU(y0 + size_in_luma_v);
 
  131             int max = 
FFMIN(size_in_luma_pu_v, 
sps->min_pu_height - y_bottom_pu);
 
  132             cand_bottom_left = 0;
 
  133             for (
i = 0; 
i < 
max; 
i += 2)
 
  134                 cand_bottom_left |= (
MVF(x_left_pu, y_bottom_pu + 
i).pred_flag == 
PF_INTRA);
 
  136         if (cand_left == 1 && on_pu_edge_x) {
 
  137             int x_left_pu   = 
PU(x0 - 1);
 
  138             int y_left_pu   = 
PU(y0);
 
  139             int max = 
FFMIN(size_in_luma_pu_v, 
sps->min_pu_height - y_left_pu);
 
  141             for (
i = 0; 
i < 
max; 
i += 2)
 
  142                 cand_left |= (
MVF(x_left_pu, y_left_pu + 
i).pred_flag == 
PF_INTRA);
 
  144         if (cand_up_left == 1) {
 
  145             int x_left_pu   = 
PU(x0 - 1);
 
  146             int y_top_pu    = 
PU(y0 - 1);
 
  147             cand_up_left = 
MVF(x_left_pu, y_top_pu).pred_flag == 
PF_INTRA;
 
  149         if (cand_up == 1 && on_pu_edge_y) {
 
  150             int x_top_pu    = 
PU(x0);
 
  151             int y_top_pu    = 
PU(y0 - 1);
 
  152             int max = 
FFMIN(size_in_luma_pu_h, 
sps->min_pu_width - x_top_pu);
 
  154             for (
i = 0; 
i < 
max; 
i += 2)
 
  155                 cand_up |= (
MVF(x_top_pu + 
i, y_top_pu).pred_flag == 
PF_INTRA);
 
  157         if (cand_up_right == 1 && on_pu_edge_y) {
 
  158             int y_top_pu    = 
PU(y0 - 1);
 
  159             int x_right_pu  = 
PU(x0 + size_in_luma_h);
 
  160             int max = 
FFMIN(size_in_luma_pu_h, 
sps->min_pu_width - x_right_pu);
 
  162             for (
i = 0; 
i < 
max; 
i += 2)
 
  163                 cand_up_right |= (
MVF(x_right_pu + 
i, y_top_pu).pred_flag == 
PF_INTRA);
 
  178                size - top_right_size);
 
  183     if (cand_bottom_left) {
 
  187                size - bottom_left_size);
 
  190     if (
pps->constrained_intra_pred_flag == 1) {
 
  191         if (cand_bottom_left || cand_left || cand_up_left || cand_up || cand_up_right) {
 
  192             int size_max_x = x0 + ((2 * 
size) << hshift) < 
sps->width ?
 
  193                                     2 * 
size : (
sps->width - x0) >> hshift;
 
  194             int size_max_y = y0 + ((2 * 
size) << vshift) < 
sps->height ?
 
  195                                     2 * 
size : (
sps->height - y0) >> vshift;
 
  196             int j = 
size + (cand_bottom_left? bottom_left_size: 0) -1;
 
  197             if (!cand_up_right) {
 
  198                 size_max_x = x0 + ((
size) << hshift) < 
sps->width ?
 
  199                              size : (
sps->width - x0) >> hshift;
 
  201             if (!cand_bottom_left) {
 
  202                 size_max_y = y0 + (( 
size) << vshift) < 
sps->height ?
 
  203                                                      size : (
sps->height - y0) >> vshift;
 
  205             if (cand_bottom_left || cand_left || cand_up_left) {
 
  210                     while (j < size_max_x && !
IS_INTRA(j, -1))
 
  217                 while (j < size_max_x && !
IS_INTRA(j, -1))
 
  226             if (cand_bottom_left || cand_left) {
 
  232             if (!cand_bottom_left)
 
  234             if (x0 != 0 && y0 != 0) {
 
  239             } 
else if (x0 == 0) {
 
  253     if (!cand_bottom_left) {
 
  256         } 
else if (cand_up_left) {
 
  259         } 
else if (cand_up) {
 
  264         } 
else if (cand_up_right) {
 
  291     if (!
sps->intra_smoothing_disabled && (c_idx == 0  || 
sps->chroma_format_idc == 3)) {
 
  293             int intra_hor_ver_dist_thresh[] = { 7, 1, 0 };
 
  296             if (min_dist_vert_hor > intra_hor_ver_dist_thresh[log2_size - 3]) {
 
  298                 if (
sps->strong_intra_smoothing_enabled && c_idx == 0 &&
 
  300                     FFABS(top[-1]  + top[63]  - 2 * top[31])  < threshold &&
 
  304                     filtered_top[-1] = top[-1];
 
  305                     filtered_top[63] = top[63];
 
  306                     for (
i = 0; 
i < 63; 
i++)
 
  307                         filtered_top[
i] = ((64 - (
i + 1)) * top[-1] +
 
  308                                            (
i + 1)  * top[63] + 32) >> 6;
 
  309                     for (
i = 0; 
i < 63; 
i++)
 
  311                                    (
i + 1)  * 
left[63] + 32) >> 6;
 
  315                     filtered_top[2 * 
size - 1]  = top[2 * 
size - 1];
 
  316                     for (
i = 2 * 
size - 2; 
i >= 0; 
i--)
 
  318                                             left[
i - 1] + 2) >> 2;
 
  320                     filtered_left[-1] = (
left[0] + 2 * 
left[-1] + top[0] + 2) >> 2;
 
  321                     for (
i = 2 * 
size - 2; 
i >= 0; 
i--)
 
  322                         filtered_top[
i] = (top[
i + 1] + 2 * top[
i] +
 
  323                                            top[
i - 1] + 2) >> 2;
 
  324                     left = filtered_left;
 
  333         s->hpc.pred_planar[log2_size - 2]((uint8_t *)
src, (uint8_t *)top,
 
  337         s->hpc.pred_dc((uint8_t *)
src, (uint8_t *)top,
 
  341         s->hpc.pred_angular[log2_size - 2]((uint8_t *)
src, (uint8_t *)top,
 
  348 #define INTRA_PRED(size)                                                            \ 
  349 static void FUNC(intra_pred_ ## size)(HEVCLocalContext *lc, const HEVCPPS *pps,     \ 
  350                                       int x0, int y0, int c_idx)                    \ 
  352     FUNC(intra_pred)(lc, pps, x0, y0, size, c_idx);                                 \ 
  363                                   const uint8_t *_left, ptrdiff_t 
stride,
 
  370     int size = 1 << trafo_size;
 
  371     for (y = 0; y < 
size; y++)
 
  372         for (x = 0; x < 
size; x++)
 
  377 #define PRED_PLANAR(size)\ 
  378 static void FUNC(pred_planar_ ## size)(uint8_t *src, const uint8_t *top,        \ 
  379                                        const uint8_t *left, ptrdiff_t stride)   \ 
  381     FUNC(pred_planar)(src, top, left, stride, size + 2);                        \ 
  392                           const uint8_t *_left,
 
  393                           ptrdiff_t 
stride, 
int log2_size, 
int c_idx)
 
  396     int size          = (1 << log2_size);
 
  405     dc >>= log2_size + 1;
 
  410         for (j = 0; j < 
size; j+=4)
 
  413     if (c_idx == 0 && 
size < 32) {
 
  414         POS(0, 0) = (
left[0] + 2 * 
dc + top[0] + 2) >> 2;
 
  415         for (x = 1; x < 
size; x++)
 
  416             POS(x, 0) = (top[x] + 3 * 
dc + 2) >> 2;
 
  417         for (y = 1; y < 
size; y++)
 
  424                                                 const uint8_t *_left,
 
  425                                                 ptrdiff_t 
stride, 
int c_idx,
 
  433     static const int intra_pred_angle[] = {
 
  434          32,  26,  21,  17, 13,  9,  5, 2, 0, -2, -5, -9, -13, -17, -21, -26, -32,
 
  435         -26, -21, -17, -13, -9, -5, -2, 0, 2,  5,  9, 13,  17,  21,  26,  32
 
  437     static const int inv_angle[] = {
 
  438         -4096, -1638, -910, -630, -482, -390, -315, -256, -315, -390, -482,
 
  439         -630, -910, -1638, -4096
 
  442     int angle = intra_pred_angle[
mode - 2];
 
  446     int last = (
size * angle) >> 5;
 
  450         if (angle < 0 && last < -1) {
 
  451             for (x = 0; x <= 
size; x += 4)
 
  453             for (x = last; x <= -1; x++)
 
  454                 ref_tmp[x] = 
left[-1 + ((x * inv_angle[
mode - 11] + 128) >> 8)];
 
  458         for (y = 0; y < 
size; y++) {
 
  459             int idx  = ((y + 1) * angle) >> 5;
 
  460             int fact = ((y + 1) * angle) & 31;
 
  462                 for (x = 0; x < 
size; x += 4) {
 
  463                     POS(x    , y) = ((32 - 
fact) * 
ref[x + idx + 1] +
 
  464                                            fact  * 
ref[x + idx + 2] + 16) >> 5;
 
  465                     POS(x + 1, y) = ((32 - 
fact) * 
ref[x + 1 + idx + 1] +
 
  466                                            fact  * 
ref[x + 1 + idx + 2] + 16) >> 5;
 
  467                     POS(x + 2, y) = ((32 - 
fact) * 
ref[x + 2 + idx + 1] +
 
  468                                            fact  * 
ref[x + 2 + idx + 2] + 16) >> 5;
 
  469                     POS(x + 3, y) = ((32 - 
fact) * 
ref[x + 3 + idx + 1] +
 
  470                                            fact  * 
ref[x + 3 + idx + 2] + 16) >> 5;
 
  473                 for (x = 0; x < 
size; x += 4)
 
  477         if (
mode == 26 && c_idx == 0 && 
size < 32) {
 
  478             for (y = 0; y < 
size; y++)
 
  483         if (angle < 0 && last < -1) {
 
  484             for (x = 0; x <= 
size; x += 4)
 
  486             for (x = last; x <= -1; x++)
 
  487                 ref_tmp[x] = top[-1 + ((x * inv_angle[
mode - 11] + 128) >> 8)];
 
  491         for (x = 0; x < 
size; x++) {
 
  492             int idx  = ((x + 1) * angle) >> 5;
 
  493             int fact = ((x + 1) * angle) & 31;
 
  495                 for (y = 0; y < 
size; y++) {
 
  497                                        fact  * 
ref[y + idx + 2] + 16) >> 5;
 
  500                 for (y = 0; y < 
size; y++)
 
  501                     POS(x, y) = 
ref[y + idx + 1];
 
  504         if (
mode == 10 && c_idx == 0 && 
size < 32) {
 
  505             for (x = 0; x < 
size; x += 4) {
 
  543 #undef EXTEND_LEFT_CIP 
  544 #undef EXTEND_RIGHT_CIP 
  546 #undef EXTEND_DOWN_CIP 
  552 #undef MIN_TB_ADDR_ZS 
  
static void FUNC() pred_angular_3(uint8_t *src, const uint8_t *top, const uint8_t *left, ptrdiff_t stride, int c_idx, int mode)
 
#define PRED_PLANAR(size)
 
uint8_t ptrdiff_t const uint8_t * _src
 
#define EXTEND_LEFT_CIP(ptr, start, length)
 
#define MIN_TB_ADDR_ZS(x, y)
 
static av_always_inline void FUNC() intra_pred(HEVCLocalContext *lc, const HEVCPPS *pps, int x0, int y0, int log2_size, int c_idx)
 
#define EXTEND_DOWN_CIP(ptr, start, length)
 
static void FUNC() pred_angular_2(uint8_t *src, const uint8_t *top, const uint8_t *left, ptrdiff_t stride, int c_idx, int mode)
 
#define PIXEL_SPLAT_X4(x)
 
#define FFABS(a)
Absolute value, Note, INT_MIN / INT64_MIN result in undefined behavior as they are not representable ...
 
static av_always_inline void FUNC() pred_angular(uint8_t *_src, const uint8_t *_top, const uint8_t *_left, ptrdiff_t stride, int c_idx, int mode, int size)
 
#define EXTEND_UP_CIP(ptr, start, length)
 
#define EXTEND_RIGHT_CIP(ptr, start, length)
 
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]
 
static void FUNC() pred_angular_0(uint8_t *src, const uint8_t *top, const uint8_t *left, ptrdiff_t stride, int c_idx, int mode)
 
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
 
static double fact(double i)
 
static void FUNC() pred_dc(uint8_t *_src, const uint8_t *_top, const uint8_t *_left, ptrdiff_t stride, int log2_size, int c_idx)
 
#define i(width, name, range_min, range_max)
 
static int FUNC() sps(CodedBitstreamContext *ctx, RWContext *rw, H264RawSPS *current)
 
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
 
static void FUNC() pred_angular_1(uint8_t *src, const uint8_t *top, const uint8_t *left, ptrdiff_t stride, int c_idx, int mode)
 
static int ref[MAX_W *MAX_W]
 
#define EXTEND(ptr, val, len)
 
static av_always_inline void FUNC() pred_planar(uint8_t *_src, const uint8_t *_top, const uint8_t *_left, ptrdiff_t stride, int trafo_size)