[FFmpeg-devel] [PATCH] RV40 Loop Filter (again)
Kostya
kostya.shishkov
Wed Nov 12 08:05:11 CET 2008
$subj
-------------- next part --------------
Index: rv40.c
===================================================================
--- rv40.c (revision 15732)
+++ rv40.c (working copy)
@@ -247,7 +247,431 @@
return 0;
}
+#define CLIP_SYMM(a, b) av_clip(a, -(b), b)
/**
+ * weaker deblocking very similar to the one described in 4.4.2 of JVT-A003r1
+ *
+ * @param filter_outer flag signalling that pixels at distance 2 from the edge
+ * should be filtered
+ * @param filter_inner flag signalling that pixels at distance 1 from the edge
+ * should be filtered (pixels at the edge are always filtered)
+ */
+static inline void rv40_weak_loop_filter(uint8_t *src, const int step,
+ const int filter_outer, const int filter_inner,
+ const int alpha, const int beta,
+ const int lim0, const int lim1, const int lim2,
+ const int diff_p1p0, const int diff_q1q0,
+ const int diff_p1p2, const int diff_q1q2)
+{
+ uint8_t *cm = ff_cropTbl + MAX_NEG_CROP;
+ int t, u, diff;
+
+ t = src[0*step] - src[-1*step];
+ if(!t)
+ return;
+ u = (alpha * FFABS(t)) >> 7;
+ if(u > 3 - (filter_inner && filter_outer))
+ return;
+
+ t <<= 2;
+ if(filter_inner && filter_outer)
+ t += src[-2*step] - src[1*step];
+ diff = CLIP_SYMM((t + 4) >> 3, lim0);
+ src[-1*step] = cm[src[-1*step] + diff];
+ src[ 0*step] = cm[src[ 0*step] - diff];
+ if(FFABS(diff_p1p2) <= beta && filter_outer){
+ t = (diff_p1p0 + diff_p1p2 - diff) >> 1;
+ src[-2*step] = cm[src[-2*step] - CLIP_SYMM(t, lim2)];
+ }
+ if(FFABS(diff_q1q2) <= beta && filter_inner){
+ t = (diff_q1q0 + diff_q1q2 + diff) >> 1;
+ src[ 1*step] = cm[src[ 1*step] - CLIP_SYMM(t, lim1)];
+ }
+}
+
+/**
+ * RV4 strong edge filter with coefficients (25 26 26 26 25)
+ */
+#define RV40_STRONG_FILTER(src, step, start, bias) \
+ (25*src[(start-2)*step] + 26*src[(start-1)*step] + 26*src[start*step] + \
+ 26*src[(start+1)*step] + 25*src[(start+2)*step] + bias) >> 7
+
+/**
+ * RV4 strong edge filter for outermost pixels with coefficients effectively
+ * (25 26 51 26) because of mirroring - for the case when edge to be filtered
+ * lies to the left (or bottom) of the filtered pixel
+ */
+#define RV40_STRONG_FILTER_LEFT(src, step) \
+ (25*src[-1*step] + 26*src[-2*step] + 51*src[-3*step] + 26*src[-4*step] + 64) >> 7
+
+/**
+ * RV4 strong edge filter for outermost pixels with coefficients effectively
+ * (25 26 51 26) because of mirroring - for the case when edge to be filtered
+ * lies to the right (or top) of the filtered pixel
+ */
+#define RV40_STRONG_FILTER_RIGHT(src, step) \
+ (25*src[0*step] + 26*src[1*step] + 51*src[2*step] + 26*src[3*step] + 64) >> 7
+
+/**
+ * Deblocking filter, the altered version from JVT-A003r1 H.26L draft.
+ */
+static inline void rv40_adaptive_loop_filter(uint8_t *src, const int step,
+ const int stride, const int dmode,
+ const int lim_inner, const int lim_outer,
+ const int alpha,
+ const int beta, const int beta2,
+ const int chroma, const int edge)
+{
+ int diff_p1p0[4], diff_q1q0[4], diff_p1p2[4], diff_q1q2[4];
+ int s0 = 0, s1 = 0, s2 = 0, s3 = 0;
+ uint8_t *ptr;
+ int flag_strong0 = 1, flag_strong1 = 1;
+ int strength0 = 3, strength1 = 3;
+ int i;
+ int lims;
+
+ for(i = 0, ptr = src; i < 4; i++, ptr += stride){
+ diff_p1p0[i] = ptr[-2*step] - ptr[-1*step];
+ diff_q1q0[i] = ptr[ 1*step] - ptr[ 0*step];
+ s0 += diff_p1p0[i];
+ s1 += diff_q1q0[i];
+ }
+ if(FFABS(s0) >= (beta<<2))
+ strength0 = 1;
+ if(FFABS(s1) >= (beta<<2))
+ strength1 = 1;
+ if(strength0 + strength1 <= 2)
+ return;
+
+ for(i = 0, ptr = src; i < 4; i++, ptr += stride){
+ diff_p1p2[i] = ptr[-2*step] - ptr[-3*step];
+ diff_q1q2[i] = ptr[ 1*step] - ptr[ 2*step];
+ s2 += diff_p1p2[i];
+ s3 += diff_q1q2[i];
+ }
+
+ if(!edge){
+ flag_strong0 = flag_strong1 = 0;
+ }else{
+ flag_strong0 = (strength0 == 3) && (FFABS(s2) < beta2);
+ flag_strong1 = (strength1 == 3) && (FFABS(s3) < beta2);
+ }
+
+ lims = (lim_inner + lim_outer + strength0 + strength1) >> 1;
+ if(flag_strong0 && flag_strong1){ /* strong filtering */
+ for(i = 0; i < 4; i++, src += stride){
+ int diff[2], sflag, p0, p1;
+ int t = src[0*step] - src[-1*step];
+
+ if(!t) continue;
+ sflag = (alpha * FFABS(t)) >> 7;
+ if(sflag > 1) continue;
+
+ p0 = RV40_STRONG_FILTER(src, step, -1, rv40_dither_l[dmode + i]);
+ p1 = RV40_STRONG_FILTER(src, step, 0, rv40_dither_r[dmode + i]);
+ diff[0] = src[-1*step];
+ diff[1] = src[ 0*step];
+ src[-1*step] = sflag ? av_clip(p0, src[-1*step] - lims, src[-1*step] + lims) : p0;
+ src[ 0*step] = sflag ? av_clip(p1, src[ 0*step] - lims, src[ 0*step] + lims) : p1;
+ diff[0] -= src[-1*step];
+ diff[1] -= src[ 0*step];
+ p0 = RV40_STRONG_FILTER(src, step, -2, rv40_dither_l[dmode + i] + diff[1]*25);
+ p1 = RV40_STRONG_FILTER(src, step, 1, rv40_dither_r[dmode + i] + diff[0]*25);
+ src[-2*step] = sflag ? av_clip(p0, src[-2*step] - lims, src[-2*step] + lims) : p0;
+ src[ 1*step] = sflag ? av_clip(p1, src[ 1*step] - lims, src[ 1*step] + lims) : p1;
+ if(!chroma){
+ src[-3*step] = RV40_STRONG_FILTER_LEFT (src, step);
+ src[ 2*step] = RV40_STRONG_FILTER_RIGHT(src, step);
+ }
+ }
+ }else if(strength0 == 3 && strength1 == 3){
+ for(i = 0; i < 4; i++, src += stride)
+ rv40_weak_loop_filter(src, step, 1, 1, alpha, beta, lims, lim_inner, lim_outer,
+ diff_p1p0[i], diff_q1q0[i], diff_p1p2[i], diff_q1q2[i]);
+ }else{
+ for(i = 0; i < 4; i++, src += stride)
+ rv40_weak_loop_filter(src, step, strength0==3, strength1==3,
+ alpha, beta, lims>>1, lim_inner>>1, lim_outer>>1,
+ diff_p1p0[i], diff_q1q0[i], diff_p1p2[i], diff_q1q2[i]);
+ }
+}
+
+static void rv40_v_loop_filter(uint8_t *src, int stride, int dmode,
+ int lim_inner, int lim_outer,
+ int alpha, int beta, int beta2, int chroma, int edge){
+ rv40_adaptive_loop_filter(src, 1, stride, dmode, lim_inner, lim_outer,
+ alpha, beta, beta2, chroma, edge);
+}
+static void rv40_h_loop_filter(uint8_t *src, int stride, int dmode,
+ int lim_inner, int lim_outer,
+ int alpha, int beta, int beta2, int chroma, int edge){
+ rv40_adaptive_loop_filter(src, stride, 1, dmode, lim_inner, lim_outer,
+ alpha, beta, beta2, chroma, edge);
+}
+
+enum RV40BlockPos{
+ POS_CUR,
+ POS_TOP,
+ POS_LEFT,
+ POS_BOTTOM,
+};
+
+#define MASK_CUR 0x0001
+#define MASK_RIGHT 0x0008
+#define MASK_BOTTOM 0x0010
+#define MASK_TOP 0x1000
+#define MASK_Y_TOP_ROW 0x000F
+#define MASK_Y_LAST_ROW 0xF000
+#define MASK_Y_LEFT_COL 0x1111
+#define MASK_Y_RIGHT_COL 0x8888
+#define MASK_C_TOP_ROW 0x0003
+#define MASK_C_LAST_ROW 0x000C
+#define MASK_C_LEFT_COL 0x0005
+#define MASK_C_RIGHT_COL 0x000A
+
+/**
+ * RV40 loop filtering function
+ */
+static void rv40_loop_filter(RV34DecContext *r)
+{
+ MpegEncContext *s = &r->s;
+ int mb_pos;
+ int i, j, k;
+ uint8_t *Y, *C;
+ int alpha, beta, betaY, betaC;
+ int q;
+ int mbtype[4]; ///< current macroblock and its neighbours types
+ /**
+ * macroblock filtering strength
+ * 2 for intra coded MB and MB with DCs coded separately, 1 otherwise
+ */
+ int strength[4];
+ int clip[4]; ///< MB filter clipping value calculated from filtering strength
+ /**
+ * coded block patterns for luma part of current macroblock and its neighbours
+ * Format:
+ * LSB corresponds to the top left block,
+ * each nibble represents one row of subblocks.
+ */
+ int cbp[4];
+ /**
+ * coded block patterns for chroma part of current macroblock and its neighbours
+ * Format is the same as for luma with two subblocks in a row.
+ */
+ int uvcbp[4][2];
+ /**
+ * This mask represents the pattern of luma subblocks that should be filtered
+ * in addition to the coded ones because because they lie at the edge of
+ * 8x8 block with different enough motion vectors
+ * (see rv40_set_deblock_coef() for the details)
+ */
+ int mvmasks[4];
+
+ for(s->mb_y = 0; s->mb_y < s->mb_height; s->mb_y++){
+ mb_pos = s->mb_y * s->mb_stride;
+ for(s->mb_x = 0; s->mb_x < s->mb_width; s->mb_x++, mb_pos++){
+ int btype = s->current_picture_ptr->mb_type[mb_pos];
+ if(IS_INTRA(btype) || IS_SEPARATE_DC(btype))
+ r->cbp_luma [mb_pos] = 0xFFFF;
+ if(IS_INTRA(btype))
+ r->cbp_chroma[mb_pos] = 0xFF;
+ }
+ }
+ for(s->mb_y = 0; s->mb_y < s->mb_height; s->mb_y++){
+ mb_pos = s->mb_y * s->mb_stride;
+ for(s->mb_x = 0; s->mb_x < s->mb_width; s->mb_x++, mb_pos++){
+ int y_h_deblock, y_v_deblock;
+ int c_v_deblock[2], c_h_deblock[2];
+ int clip_left;
+
+ ff_init_block_index(s);
+ ff_update_block_index(s);
+ Y = s->dest[0];
+ q = s->current_picture_ptr->qscale_table[mb_pos];
+ alpha = rv40_alpha_tab[q];
+ beta = rv40_beta_tab [q];
+ betaY = betaC = beta * 3;
+ if(s->width * s->height <= 176*144)
+ betaY += beta;
+
+ mvmasks[POS_CUR] = r->deblock_coefs[mb_pos];
+ mbtype [POS_CUR] = s->current_picture_ptr->mb_type[mb_pos];
+ cbp [POS_CUR] = r->cbp_luma[mb_pos];
+ uvcbp[POS_CUR][0] = r->cbp_chroma[mb_pos] & 0xF;
+ uvcbp[POS_CUR][1] = r->cbp_chroma[mb_pos] >> 4;
+ for(i = 1; i < 4; i++){
+ mvmasks[i] = 0;
+ mbtype [i] = mbtype[0];
+ cbp [i] = 0;
+ uvcbp[1][0] = uvcbp[1][1] = 0;
+ }
+ if(s->mb_y){
+ mvmasks[POS_TOP] = r->deblock_coefs[mb_pos - s->mb_stride] & MASK_Y_LAST_ROW;
+ mbtype [POS_TOP] = s->current_picture_ptr->mb_type[mb_pos - s->mb_stride];
+ cbp [POS_TOP] = r->cbp_luma[mb_pos - s->mb_stride] & MASK_Y_LAST_ROW;
+ uvcbp[POS_TOP][0] = r->cbp_chroma[mb_pos - s->mb_stride] & MASK_C_LAST_ROW;
+ uvcbp[POS_TOP][1] = (r->cbp_chroma[mb_pos - s->mb_stride] >> 4) & MASK_C_LAST_ROW;
+ }
+ if(s->mb_x){
+ mvmasks[POS_LEFT] = r->deblock_coefs[mb_pos - 1] & MASK_Y_RIGHT_COL;
+ mbtype [POS_LEFT] = s->current_picture_ptr->mb_type[mb_pos - 1];
+ cbp [POS_LEFT] = r->cbp_luma[mb_pos - 1] & MASK_Y_RIGHT_COL;
+ uvcbp[POS_LEFT][0] = r->cbp_chroma[mb_pos - 1] & MASK_C_RIGHT_COL;
+ uvcbp[POS_LEFT][1] = (r->cbp_chroma[mb_pos - 1] >> 4) & MASK_C_RIGHT_COL;
+ }
+ if(s->mb_y < s->mb_height - 1){
+ mvmasks[POS_BOTTOM] = r->deblock_coefs[mb_pos + s->mb_stride] & MASK_Y_TOP_ROW;
+ mbtype [POS_BOTTOM] = s->current_picture_ptr->mb_type[mb_pos + s->mb_stride];
+ cbp [POS_BOTTOM] = r->cbp_luma[mb_pos + s->mb_stride] & MASK_Y_TOP_ROW;
+ uvcbp[POS_BOTTOM][0] = r->cbp_chroma[mb_pos + s->mb_stride] & MASK_C_TOP_ROW;
+ uvcbp[POS_BOTTOM][1] = (r->cbp_chroma[mb_pos + s->mb_stride] >> 4) & MASK_C_TOP_ROW;
+ }
+ for(i = 0; i < 4; i++){
+ strength[i] = (IS_INTRA(mbtype[i]) || IS_SEPARATE_DC(mbtype[i])) ? 2 : 1;
+ clip[i] = rv40_filter_clip_tbl[strength[i]][q];
+ }
+ /* This pattern contains bits signalling that horizontal edges of
+ * the current block can be filtered.
+ * That happens when either of adjacent subblocks is coded or lies on
+ * the edge of 8x8 blocks with motion vectors differing by more than
+ * 3/4 pel in any component.
+ */
+ y_h_deblock = cbp[POS_CUR] | (cbp[POS_BOTTOM] << 16)
+ | ((cbp[POS_CUR] << 4) & ~MASK_Y_TOP_ROW) | (cbp[POS_TOP] >> 12)
+ | mvmasks[POS_CUR] | (mvmasks[POS_BOTTOM] << 16);
+ /* This pattern contains bits signalling that vertical edges of
+ * the current block can be filtered.
+ * That happens when either of adjacent subblocks is coded or lies on
+ * the edge of 8x8 blocks with motion vectors differing by more than
+ * 3/4 pel in any component.
+ */
+ y_v_deblock = cbp[POS_CUR]
+ | ((cbp[POS_CUR] << 1) & ~MASK_Y_LEFT_COL) | (cbp[POS_LEFT] >> 3)
+ | mvmasks[0];
+ if(!s->mb_x)
+ y_v_deblock &= ~MASK_Y_LEFT_COL;
+ if(!s->mb_y)
+ y_h_deblock &= ~MASK_Y_TOP_ROW;
+ if(s->mb_y == s->mb_height - 1 || (strength[POS_CUR] == 2 || strength[POS_BOTTOM] == 2))
+ y_h_deblock &= ~(MASK_Y_TOP_ROW << 16);
+ /* We should add motion vector mask and the bottom CBP to the current
+ * CBP since it's checked in this combination afterwards.
+ */
+ cbp[POS_CUR] = cbp[POS_CUR] | (cbp[POS_BOTTOM] << 16)
+ | mvmasks[POS_CUR] | (mvmasks[POS_BOTTOM] << 16);
+ /* Calculating chroma patterns is similar and easier since there is
+ * no motion vector pattern for them.
+ */
+ for(i = 0; i < 2; i++){
+ c_v_deblock[i] = ((uvcbp[POS_CUR][i] << 1) & ~MASK_C_RIGHT_COL) | (uvcbp[POS_LEFT][i] >> 1)
+ | (uvcbp[POS_BOTTOM][i] << 4) | uvcbp[POS_CUR][i];
+ c_h_deblock[i] = (uvcbp[POS_BOTTOM][i] << 4) | uvcbp[POS_CUR][i] | (uvcbp[POS_TOP][i] >> 2)
+ | (uvcbp[POS_BOTTOM][i] << 6) | (uvcbp[POS_CUR][i] << 2);
+ uvcbp[POS_CUR][i] = (uvcbp[POS_BOTTOM][i] << 4) | uvcbp[POS_CUR][i];
+ if(!s->mb_x)
+ c_v_deblock[i] &= ~MASK_C_LEFT_COL;
+ if(!s->mb_y)
+ c_h_deblock[i] &= ~MASK_C_TOP_ROW;
+ if(s->mb_y == s->mb_height - 1 || strength[POS_CUR] == 2 || strength[POS_BOTTOM] == 2)
+ c_h_deblock[i] &= ~(MASK_C_TOP_ROW << 4);
+ }
+
+ for(j = 0; j < 16; j += 4){
+ Y = s->dest[0] + j * s->linesize;
+ for(i = 0; i < 4; i++, Y += 4){
+ int ij = i + j;
+ int clip_cur = cbp[POS_CUR] & (MASK_CUR << ij) ? clip[POS_CUR] : 0;
+ int dither = j ? ij : i*4;
+
+ // if bottom block is coded then we can filter its top edge
+ // (or bottom edge of this block, which is the same)
+ if(y_h_deblock & (MASK_BOTTOM << ij)){
+ rv40_h_loop_filter(Y+4*s->linesize, s->linesize, dither,
+ cbp[POS_CUR] & (MASK_BOTTOM << ij) ? clip[POS_CUR] : 0,
+ clip_cur,
+ alpha, beta, betaY, 0, 0);
+ }
+ // filter left block edge in ordinary mode (with low filtering strength)
+ if(y_v_deblock & (MASK_CUR << ij)
+ && (i || !(strength[POS_CUR] == 2 || strength[POS_LEFT] == 2))){
+ if(!i){
+ clip_left = cbp[POS_LEFT] & (MASK_RIGHT << j) ? clip[POS_LEFT] : 0;
+ }else{
+ clip_left = cbp[POS_CUR] & (MASK_CUR << (ij-1)) ? clip[POS_CUR] : 0;
+ }
+ rv40_v_loop_filter(Y, s->linesize, dither,
+ clip_cur,
+ clip_left,
+ alpha, beta, betaY, 0, 0);
+ }
+ // filter top edge of the current macroblock when filtering strength is high
+ if(!j && y_h_deblock & (MASK_CUR << i)
+ && (strength[POS_CUR] == 2 || strength[POS_TOP] == 2)){
+ rv40_h_loop_filter(Y, s->linesize, dither,
+ clip_cur,
+ cbp[POS_TOP] & (MASK_TOP << i) ? clip[POS_TOP] : 0,
+ alpha, beta, betaY, 0, 1);
+ }
+ // filter left block edge in edge mode (with high filtering strength)
+ if(y_v_deblock & (MASK_CUR << ij) && !i
+ && (strength[POS_CUR] == 2 || strength[POS_LEFT] == 2)){
+ clip_left = cbp[POS_LEFT] & (MASK_RIGHT << j) ? clip[POS_LEFT] : 0;
+ rv40_v_loop_filter(Y, s->linesize, dither,
+ clip_cur,
+ clip_left,
+ alpha, beta, betaY, 0, 1);
+ }
+ }
+ }
+ for(k = 0; k < 2; k++){
+ for(j = 0; j < 2; j++){
+ C = s->dest[k] + j * 4 * s->uvlinesize;
+ for(i = 0; i < 2; i++, C += 4){
+ int ij = i + j*2;
+ int clip_cur = uvcbp[POS_CUR][k] & (MASK_CUR << ij) ? clip[POS_CUR] : 0;
+ if(c_h_deblock[k] & (MASK_CUR << (ij+2))){
+ int clip_bot = uvcbp[POS_CUR][k] & (MASK_CUR << (ij+2)) ? clip[POS_CUR] : 0;
+ rv40_h_loop_filter(C+4*s->uvlinesize, s->uvlinesize, i*8,
+ clip_bot,
+ clip_cur,
+ alpha, beta, betaC, 1, 0);
+ }
+ if((c_v_deblock[k] & (MASK_CUR << ij))
+ && (i || !(strength[POS_CUR] == 2 || strength[POS_LEFT] == 2))){
+ if(!i){
+ clip_left = uvcbp[POS_LEFT][k] & (MASK_CUR << (2*j+1)) ? clip[POS_LEFT] : 0;
+ }else{
+ clip_left = uvcbp[POS_CUR][k] & (MASK_CUR << (ij-1)) ? clip[POS_CUR] : 0;
+ }
+ rv40_v_loop_filter(C, s->uvlinesize, j*8,
+ clip_cur,
+ clip_left,
+ alpha, beta, betaY, 1, 0);
+ }
+ if(!j && c_h_deblock[k] & (MASK_CUR << ij)
+ && (strength[POS_CUR] == 2 || strength[POS_TOP] == 2)){
+ int clip_top = uvcbp[POS_TOP][k] & (MASK_CUR << (ij+2)) ? clip[POS_TOP] : 0;
+ rv40_h_loop_filter(C, s->uvlinesize, i*8,
+ clip_cur,
+ clip_top,
+ alpha, beta, betaC, 1, 1);
+ }
+ if(c_v_deblock[k] & (MASK_CUR << ij)
+ && !i && (strength[POS_CUR] == 2 || strength[POS_LEFT] == 2)){
+ clip_left = uvcbp[POS_LEFT][k] & (MASK_CUR << (2*j+1)) ? clip[POS_LEFT] : 0;
+ rv40_v_loop_filter(C, s->uvlinesize, j*8,
+ clip_cur,
+ clip_left,
+ alpha, beta, betaY, 1, 1);
+ }
+ }
+ }
+ }
+ }
+ }
+}
+
+/**
* Initialize decoder.
*/
static av_cold int rv40_decode_init(AVCodecContext *avctx)
@@ -261,6 +685,7 @@
r->parse_slice_header = rv40_parse_slice_header;
r->decode_intra_types = rv40_decode_intra_types;
r->decode_mb_info = rv40_decode_mb_info;
+ r->loop_filter = rv40_loop_filter;
r->luma_dc_quant_i = rv40_luma_dc_quant[0];
r->luma_dc_quant_p = rv40_luma_dc_quant[1];
return 0;
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