/*****************************************************************************
- * rdo.c: h264 encoder library (rate-distortion optimization)
+ * rdo.c: rate-distortion optimization
*****************************************************************************
- * Copyright (C) 2005 x264 project
+ * Copyright (C) 2005-2011 x264 project
*
* Authors: Loren Merritt <lorenm@u.washington.edu>
+ * Fiona Glaser <fiona@x264.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02111, USA.
+ *
+ * This program is also available under a commercial proprietary license.
+ * For more information, contact us at licensing@x264.com.
*****************************************************************************/
+/* duplicate all the writer functions, just calculating bit cost
+ * instead of writing the bitstream.
+ * TODO: use these for fast 1st pass too. */
+
+#define RDO_SKIP_BS 1
+
+/* Transition and size tables for abs<9 MVD and residual coding */
+/* Consist of i_prefix-2 1s, one zero, and a bypass sign bit */
+static uint8_t cabac_transition_unary[15][128];
+static uint16_t cabac_size_unary[15][128];
+/* Transition and size tables for abs>9 MVD */
+/* Consist of 5 1s and a bypass sign bit */
+static uint8_t cabac_transition_5ones[128];
+static uint16_t cabac_size_5ones[128];
+
+/* CAVLC: produces exactly the same bit count as a normal encode */
+/* this probably still leaves some unnecessary computations */
+#define bs_write1(s,v) ((s)->i_bits_encoded += 1)
+#define bs_write(s,n,v) ((s)->i_bits_encoded += (n))
+#define bs_write_ue(s,v) ((s)->i_bits_encoded += bs_size_ue(v))
+#define bs_write_se(s,v) ((s)->i_bits_encoded += bs_size_se(v))
+#define bs_write_te(s,v,l) ((s)->i_bits_encoded += bs_size_te(v,l))
+#define x264_macroblock_write_cavlc static x264_macroblock_size_cavlc
+#include "cavlc.c"
+
+/* CABAC: not exactly the same. x264_cabac_size_decision() keeps track of
+ * fractional bits, but only finite precision. */
+#undef x264_cabac_encode_decision
+#undef x264_cabac_encode_decision_noup
+#undef x264_cabac_encode_bypass
+#undef x264_cabac_encode_terminal
+#define x264_cabac_encode_decision(c,x,v) x264_cabac_size_decision(c,x,v)
+#define x264_cabac_encode_decision_noup(c,x,v) x264_cabac_size_decision_noup(c,x,v)
+#define x264_cabac_encode_terminal(c) ((c)->f8_bits_encoded += 7)
+#define x264_cabac_encode_bypass(c,v) ((c)->f8_bits_encoded += 256)
+#define x264_cabac_encode_ue_bypass(c,e,v) ((c)->f8_bits_encoded += (bs_size_ue_big(v+(1<<e)-1)-e)<<8)
+#define x264_macroblock_write_cabac static x264_macroblock_size_cabac
+#include "cabac.c"
+
+#define COPY_CABAC h->mc.memcpy_aligned( &cabac_tmp.f8_bits_encoded, &h->cabac.f8_bits_encoded, \
+ sizeof(x264_cabac_t) - offsetof(x264_cabac_t,f8_bits_encoded) - (CHROMA444 ? 0 : (1024+12)-460) )
+#define COPY_CABAC_PART( pos, size )\
+ memcpy( &cb->state[pos], &h->cabac.state[pos], size )
+
+static ALWAYS_INLINE uint64_t cached_hadamard( x264_t *h, int size, int x, int y )
+{
+ static const uint8_t hadamard_shift_x[4] = {4, 4, 3, 3};
+ static const uint8_t hadamard_shift_y[4] = {4-0, 3-0, 4-1, 3-1};
+ static const uint8_t hadamard_offset[4] = {0, 1, 3, 5};
+ int cache_index = (x >> hadamard_shift_x[size]) + (y >> hadamard_shift_y[size])
+ + hadamard_offset[size];
+ uint64_t res = h->mb.pic.fenc_hadamard_cache[cache_index];
+ if( res )
+ return res - 1;
+ else
+ {
+ pixel *fenc = h->mb.pic.p_fenc[0] + x + y*FENC_STRIDE;
+ res = h->pixf.hadamard_ac[size]( fenc, FENC_STRIDE );
+ h->mb.pic.fenc_hadamard_cache[cache_index] = res + 1;
+ return res;
+ }
+}
+
+static ALWAYS_INLINE int cached_satd( x264_t *h, int size, int x, int y )
+{
+ static const uint8_t satd_shift_x[3] = {3, 2, 2};
+ static const uint8_t satd_shift_y[3] = {2-1, 3-2, 2-2};
+ static const uint8_t satd_offset[3] = {0, 8, 16};
+ ALIGNED_16( static pixel zero[16] ) = {0};
+ int cache_index = (x >> satd_shift_x[size - PIXEL_8x4]) + (y >> satd_shift_y[size - PIXEL_8x4])
+ + satd_offset[size - PIXEL_8x4];
+ int res = h->mb.pic.fenc_satd_cache[cache_index];
+ if( res )
+ return res - 1;
+ else
+ {
+ pixel *fenc = h->mb.pic.p_fenc[0] + x + y*FENC_STRIDE;
+ int dc = h->pixf.sad[size]( fenc, FENC_STRIDE, zero, 0 ) >> 1;
+ res = h->pixf.satd[size]( fenc, FENC_STRIDE, zero, 0 ) - dc;
+ h->mb.pic.fenc_satd_cache[cache_index] = res + 1;
+ return res;
+ }
+}
+
+/* Psy RD distortion metric: SSD plus "Absolute Difference of Complexities" */
+/* SATD and SA8D are used to measure block complexity. */
+/* The difference between SATD and SA8D scores are both used to avoid bias from the DCT size. Using SATD */
+/* only, for example, results in overusage of 8x8dct, while the opposite occurs when using SA8D. */
+
+/* FIXME: Is there a better metric than averaged SATD/SA8D difference for complexity difference? */
+/* Hadamard transform is recursive, so a SATD+SA8D can be done faster by taking advantage of this fact. */
+/* This optimization can also be used in non-RD transform decision. */
+
+static inline int ssd_plane( x264_t *h, int size, int p, int x, int y )
+{
+ ALIGNED_16( static pixel zero[16] ) = {0};
+ int satd = 0;
+ pixel *fdec = h->mb.pic.p_fdec[p] + x + y*FDEC_STRIDE;
+ pixel *fenc = h->mb.pic.p_fenc[p] + x + y*FENC_STRIDE;
+ if( p == 0 && h->mb.i_psy_rd )
+ {
+ /* If the plane is smaller than 8x8, we can't do an SA8D; this probably isn't a big problem. */
+ if( size <= PIXEL_8x8 )
+ {
+ uint64_t fdec_acs = h->pixf.hadamard_ac[size]( fdec, FDEC_STRIDE );
+ uint64_t fenc_acs = cached_hadamard( h, size, x, y );
+ satd = abs((int32_t)fdec_acs - (int32_t)fenc_acs)
+ + abs((int32_t)(fdec_acs>>32) - (int32_t)(fenc_acs>>32));
+ satd >>= 1;
+ }
+ else
+ {
+ int dc = h->pixf.sad[size]( fdec, FDEC_STRIDE, zero, 0 ) >> 1;
+ satd = abs(h->pixf.satd[size]( fdec, FDEC_STRIDE, zero, 0 ) - dc - cached_satd( h, size, x, y ));
+ }
+ satd = (satd * h->mb.i_psy_rd * h->mb.i_psy_rd_lambda + 128) >> 8;
+ }
+ return h->pixf.ssd[size](fenc, FENC_STRIDE, fdec, FDEC_STRIDE) + satd;
+}
+
+static inline int ssd_mb( x264_t *h )
+{
+ int chroma_size = CHROMA444 ? PIXEL_16x16 : PIXEL_8x8;
+ int chroma_ssd = ssd_plane(h, chroma_size, 1, 0, 0) + ssd_plane(h, chroma_size, 2, 0, 0);
+ chroma_ssd = ((uint64_t)chroma_ssd * h->mb.i_chroma_lambda2_offset + 128) >> 8;
+ return ssd_plane(h, PIXEL_16x16, 0, 0, 0) + chroma_ssd;
+}
+
static int x264_rd_cost_mb( x264_t *h, int i_lambda2 )
{
- // backup mb_type because x264_macroblock_encode may change it to skip
- int i_type_bak = h->mb.i_type;
int b_transform_bak = h->mb.b_transform_8x8;
int i_ssd;
int i_bits;
+ int type_bak = h->mb.i_type;
x264_macroblock_encode( h );
- i_ssd = h->pixf.ssd[PIXEL_16x16]( h->mb.pic.p_fenc[0], h->mb.pic.i_stride[0],
- h->mb.pic.p_fdec[0], h->mb.pic.i_stride[0] )
- + h->pixf.ssd[PIXEL_8x8]( h->mb.pic.p_fenc[1], h->mb.pic.i_stride[1],
- h->mb.pic.p_fdec[1], h->mb.pic.i_stride[1] )
- + h->pixf.ssd[PIXEL_8x8]( h->mb.pic.p_fenc[2], h->mb.pic.i_stride[2],
- h->mb.pic.p_fdec[2], h->mb.pic.i_stride[2] );
+ if( h->mb.b_deblock_rdo )
+ x264_macroblock_deblock( h );
+
+ i_ssd = ssd_mb( h );
if( IS_SKIP( h->mb.i_type ) )
{
- i_bits = 1;
+ i_bits = (1 * i_lambda2 + 128) >> 8;
}
else if( h->param.b_cabac )
{
- x264_cabac_t cabac_tmp = h->cabac;
- bs_t bs_tmp = h->out.bs;
- cabac_tmp.s = &bs_tmp;
- x264_macroblock_write_cabac( h, &cabac_tmp );
- i_bits = x264_cabac_pos( &cabac_tmp ) - x264_cabac_pos( &h->cabac );
+ x264_cabac_t cabac_tmp;
+ COPY_CABAC;
+ x264_macroblock_size_cabac( h, &cabac_tmp );
+ i_bits = ( (uint64_t)cabac_tmp.f8_bits_encoded * i_lambda2 + 32768 ) >> 16;
}
else
{
- bs_t bs_tmp = h->out.bs;
- x264_macroblock_write_cavlc( h, &bs_tmp );
- i_bits = bs_pos( &bs_tmp ) - bs_pos( &h->out.bs );
+ x264_macroblock_size_cavlc( h );
+ i_bits = ( h->out.bs.i_bits_encoded * i_lambda2 + 128 ) >> 8;
}
- h->mb.i_type = i_type_bak;
+
h->mb.b_transform_8x8 = b_transform_bak;
+ h->mb.i_type = type_bak;
+
+ return i_ssd + i_bits;
+}
+
+/* partition RD functions use 8 bits more precision to avoid large rounding errors at low QPs */
+
+static uint64_t x264_rd_cost_subpart( x264_t *h, int i_lambda2, int i4, int i_pixel )
+{
+ uint64_t i_ssd, i_bits;
+
+ x264_macroblock_encode_p4x4( h, i4 );
+ if( i_pixel == PIXEL_8x4 )
+ x264_macroblock_encode_p4x4( h, i4+1 );
+ if( i_pixel == PIXEL_4x8 )
+ x264_macroblock_encode_p4x4( h, i4+2 );
+
+ i_ssd = ssd_plane( h, i_pixel, 0, block_idx_x[i4]*4, block_idx_y[i4]*4 );
+ if( CHROMA444 )
+ {
+ int chromassd = ssd_plane( h, i_pixel, 1, block_idx_x[i4]*4, block_idx_y[i4]*4 )
+ + ssd_plane( h, i_pixel, 2, block_idx_x[i4]*4, block_idx_y[i4]*4 );
+ chromassd = ((uint64_t)chromassd * h->mb.i_chroma_lambda2_offset + 128) >> 8;
+ i_ssd += chromassd;
+ }
+
+ if( h->param.b_cabac )
+ {
+ x264_cabac_t cabac_tmp;
+ COPY_CABAC;
+ x264_subpartition_size_cabac( h, &cabac_tmp, i4, i_pixel );
+ i_bits = ( (uint64_t)cabac_tmp.f8_bits_encoded * i_lambda2 + 128 ) >> 8;
+ }
+ else
+ i_bits = x264_subpartition_size_cavlc( h, i4, i_pixel );
+
+ return (i_ssd<<8) + i_bits;
+}
+
+uint64_t x264_rd_cost_part( x264_t *h, int i_lambda2, int i4, int i_pixel )
+{
+ uint64_t i_ssd, i_bits;
+ int i8 = i4 >> 2;
+ int chromassd;
+
+ if( i_pixel == PIXEL_16x16 )
+ {
+ int i_cost = x264_rd_cost_mb( h, i_lambda2 );
+ return i_cost;
+ }
+
+ if( i_pixel > PIXEL_8x8 )
+ return x264_rd_cost_subpart( h, i_lambda2, i4, i_pixel );
+
+ h->mb.i_cbp_luma = 0;
+
+ x264_macroblock_encode_p8x8( h, i8 );
+ if( i_pixel == PIXEL_16x8 )
+ x264_macroblock_encode_p8x8( h, i8+1 );
+ if( i_pixel == PIXEL_8x16 )
+ x264_macroblock_encode_p8x8( h, i8+2 );
+
+ i_ssd = ssd_plane( h, i_pixel, 0, (i8&1)*8, (i8>>1)*8 );
+ if( CHROMA444 )
+ {
+ chromassd = ssd_plane( h, i_pixel, 1, (i8&1)*8, (i8>>1)*8 )
+ + ssd_plane( h, i_pixel, 2, (i8&1)*8, (i8>>1)*8 );
+ }
+ else
+ {
+ chromassd = ssd_plane( h, i_pixel+3, 1, (i8&1)*4, (i8>>1)*4 )
+ + ssd_plane( h, i_pixel+3, 2, (i8&1)*4, (i8>>1)*4 );
+ }
+ chromassd = ((uint64_t)chromassd * h->mb.i_chroma_lambda2_offset + 128) >> 8;
+ i_ssd += chromassd;
+
+ if( h->param.b_cabac )
+ {
+ x264_cabac_t cabac_tmp;
+ COPY_CABAC;
+ x264_partition_size_cabac( h, &cabac_tmp, i8, i_pixel );
+ i_bits = ( (uint64_t)cabac_tmp.f8_bits_encoded * i_lambda2 + 128 ) >> 8;
+ }
+ else
+ i_bits = x264_partition_size_cavlc( h, i8, i_pixel ) * i_lambda2;
+
+ return (i_ssd<<8) + i_bits;
+}
+
+static uint64_t x264_rd_cost_i8x8( x264_t *h, int i_lambda2, int i8, int i_mode, pixel edge[3][48] )
+{
+ uint64_t i_ssd, i_bits;
+ int plane_count = CHROMA444 ? 3 : 1;
+ int i_qp = h->mb.i_qp;
+ h->mb.i_cbp_luma &= ~(1<<i8);
+ h->mb.b_transform_8x8 = 1;
+
+ for( int p = 0; p < plane_count; p++ )
+ {
+ x264_mb_encode_i8x8( h, p, i8, i_qp, i_mode, edge[p] );
+ i_qp = h->mb.i_chroma_qp;
+ }
+
+ i_ssd = ssd_plane( h, PIXEL_8x8, 0, (i8&1)*8, (i8>>1)*8 );
+ if( CHROMA444 )
+ {
+ int chromassd = ssd_plane( h, PIXEL_8x8, 1, (i8&1)*8, (i8>>1)*8 )
+ + ssd_plane( h, PIXEL_8x8, 2, (i8&1)*8, (i8>>1)*8 );
+ chromassd = ((uint64_t)chromassd * h->mb.i_chroma_lambda2_offset + 128) >> 8;
+ i_ssd += chromassd;
+ }
+
+ if( h->param.b_cabac )
+ {
+ x264_cabac_t cabac_tmp;
+ COPY_CABAC;
+ x264_partition_i8x8_size_cabac( h, &cabac_tmp, i8, i_mode );
+ i_bits = ( (uint64_t)cabac_tmp.f8_bits_encoded * i_lambda2 + 128 ) >> 8;
+ }
+ else
+ i_bits = x264_partition_i8x8_size_cavlc( h, i8, i_mode ) * i_lambda2;
+
+ return (i_ssd<<8) + i_bits;
+}
+
+static uint64_t x264_rd_cost_i4x4( x264_t *h, int i_lambda2, int i4, int i_mode )
+{
+ uint64_t i_ssd, i_bits;
+ int plane_count = CHROMA444 ? 3 : 1;
+ int i_qp = h->mb.i_qp;
+
+ for( int p = 0; p < plane_count; p++ )
+ {
+ x264_mb_encode_i4x4( h, p, i4, i_qp, i_mode );
+ i_qp = h->mb.i_chroma_qp;
+ }
+
+ i_ssd = ssd_plane( h, PIXEL_4x4, 0, block_idx_x[i4]*4, block_idx_y[i4]*4 );
+ if( CHROMA444 )
+ {
+ int chromassd = ssd_plane( h, PIXEL_4x4, 1, block_idx_x[i4]*4, block_idx_y[i4]*4 )
+ + ssd_plane( h, PIXEL_4x4, 2, block_idx_x[i4]*4, block_idx_y[i4]*4 );
+ chromassd = ((uint64_t)chromassd * h->mb.i_chroma_lambda2_offset + 128) >> 8;
+ i_ssd += chromassd;
+ }
+
+ if( h->param.b_cabac )
+ {
+ x264_cabac_t cabac_tmp;
+ COPY_CABAC;
+ x264_partition_i4x4_size_cabac( h, &cabac_tmp, i4, i_mode );
+ i_bits = ( (uint64_t)cabac_tmp.f8_bits_encoded * i_lambda2 + 128 ) >> 8;
+ }
+ else
+ i_bits = x264_partition_i4x4_size_cavlc( h, i4, i_mode ) * i_lambda2;
+
+ return (i_ssd<<8) + i_bits;
+}
+
+static uint64_t x264_rd_cost_i8x8_chroma( x264_t *h, int i_lambda2, int i_mode, int b_dct )
+{
+ uint64_t i_ssd, i_bits;
+
+ if( b_dct )
+ x264_mb_encode_8x8_chroma( h, 0, h->mb.i_chroma_qp );
+ i_ssd = ssd_plane( h, PIXEL_8x8, 1, 0, 0 ) +
+ ssd_plane( h, PIXEL_8x8, 2, 0, 0 );
+
+ h->mb.i_chroma_pred_mode = i_mode;
+
+ if( h->param.b_cabac )
+ {
+ x264_cabac_t cabac_tmp;
+ COPY_CABAC;
+ x264_i8x8_chroma_size_cabac( h, &cabac_tmp );
+ i_bits = ( (uint64_t)cabac_tmp.f8_bits_encoded * i_lambda2 + 128 ) >> 8;
+ }
+ else
+ i_bits = x264_i8x8_chroma_size_cavlc( h ) * i_lambda2;
+
+ return (i_ssd<<8) + i_bits;
+}
+/****************************************************************************
+ * Trellis RD quantization
+ ****************************************************************************/
+
+#define TRELLIS_SCORE_MAX ((uint64_t)1<<50)
+#define CABAC_SIZE_BITS 8
+#define SSD_WEIGHT_BITS 5
+#define LAMBDA_BITS 4
+
+/* precalculate the cost of coding various combinations of bits in a single context */
+void x264_rdo_init( void )
+{
+ for( int i_prefix = 0; i_prefix < 15; i_prefix++ )
+ {
+ for( int i_ctx = 0; i_ctx < 128; i_ctx++ )
+ {
+ int f8_bits = 0;
+ uint8_t ctx = i_ctx;
+
+ for( int i = 1; i < i_prefix; i++ )
+ f8_bits += x264_cabac_size_decision2( &ctx, 1 );
+ if( i_prefix > 0 && i_prefix < 14 )
+ f8_bits += x264_cabac_size_decision2( &ctx, 0 );
+ f8_bits += 1 << CABAC_SIZE_BITS; //sign
+
+ cabac_size_unary[i_prefix][i_ctx] = f8_bits;
+ cabac_transition_unary[i_prefix][i_ctx] = ctx;
+ }
+ }
+ for( int i_ctx = 0; i_ctx < 128; i_ctx++ )
+ {
+ int f8_bits = 0;
+ uint8_t ctx = i_ctx;
+
+ for( int i = 0; i < 5; i++ )
+ f8_bits += x264_cabac_size_decision2( &ctx, 1 );
+ f8_bits += 1 << CABAC_SIZE_BITS; //sign
+
+ cabac_size_5ones[i_ctx] = f8_bits;
+ cabac_transition_5ones[i_ctx] = ctx;
+ }
+}
+
+typedef struct
+{
+ int64_t score;
+ int level_idx; // index into level_tree[]
+ uint8_t cabac_state[10]; //just the contexts relevant to coding abs_level_m1
+} trellis_node_t;
+
+// TODO:
+// save cabac state between blocks?
+// use trellis' RD score instead of x264_mb_decimate_score?
+// code 8x8 sig/last flags forwards with deadzone and save the contexts at
+// each position?
+// change weights when using CQMs?
+
+// possible optimizations:
+// make scores fit in 32bit
+// save quantized coefs during rd, to avoid a duplicate trellis in the final encode
+// if trellissing all MBRD modes, finish SSD calculation so we can skip all of
+// the normal dequant/idct/ssd/cabac
+
+// the unquant_mf here is not the same as dequant_mf:
+// in normal operation (dct->quant->dequant->idct) the dct and idct are not
+// normalized. quant/dequant absorb those scaling factors.
+// in this function, we just do (quant->unquant) and want the output to be
+// comparable to the input. so unquant is the direct inverse of quant,
+// and uses the dct scaling factors, not the idct ones.
+
+static ALWAYS_INLINE
+int quant_trellis_cabac( x264_t *h, dctcoef *dct,
+ const udctcoef *quant_mf, const int *unquant_mf,
+ const int *coef_weight, const uint8_t *zigzag,
+ int ctx_block_cat, int i_lambda2, int b_ac,
+ int b_chroma, int dc, int i_coefs, int idx )
+{
+ int abs_coefs[64], signs[64];
+ trellis_node_t nodes[2][8];
+ trellis_node_t *nodes_cur = nodes[0];
+ trellis_node_t *nodes_prev = nodes[1];
+ trellis_node_t *bnode;
+ const int b_interlaced = MB_INTERLACED;
+ uint8_t *cabac_state_sig = &h->cabac.state[ significant_coeff_flag_offset[b_interlaced][ctx_block_cat] ];
+ uint8_t *cabac_state_last = &h->cabac.state[ last_coeff_flag_offset[b_interlaced][ctx_block_cat] ];
+ const int f = 1 << 15; // no deadzone
+ int i_last_nnz;
+ int i;
+
+ // (# of coefs) * (# of ctx) * (# of levels tried) = 1024
+ // we don't need to keep all of those: (# of coefs) * (# of ctx) would be enough,
+ // but it takes more time to remove dead states than you gain in reduced memory.
+ struct
+ {
+ uint16_t abs_level;
+ uint16_t next;
+ } level_tree[64*8*2];
+ int i_levels_used = 1;
+
+ /* init coefs */
+ for( i = i_coefs-1; i >= b_ac; i-- )
+ if( (unsigned)(dct[zigzag[i]] * (dc?quant_mf[0]>>1:quant_mf[zigzag[i]]) + f-1) >= 2*f )
+ break;
+
+ if( i < b_ac )
+ {
+ /* We only need to zero an empty 4x4 block. 8x8 can be
+ implicitly emptied via zero nnz, as can dc. */
+ if( i_coefs == 16 && !dc )
+ memset( dct, 0, 16 * sizeof(dctcoef) );
+ return 0;
+ }
- return i_ssd + i_bits * i_lambda2;
+ i_last_nnz = i;
+ idx &= i_coefs == 64 ? 3 : 15;
+
+ for( ; i >= b_ac; i-- )
+ {
+ int coef = dct[zigzag[i]];
+ abs_coefs[i] = abs(coef);
+ signs[i] = coef < 0 ? -1 : 1;
+ }
+
+ /* init trellis */
+ for( int j = 1; j < 8; j++ )
+ nodes_cur[j].score = TRELLIS_SCORE_MAX;
+ nodes_cur[0].score = 0;
+ nodes_cur[0].level_idx = 0;
+ level_tree[0].abs_level = 0;
+ level_tree[0].next = 0;
+
+ // coefs are processed in reverse order, because that's how the abs value is coded.
+ // last_coef and significant_coef flags are normally coded in forward order, but
+ // we have to reverse them to match the levels.
+ // in 4x4 blocks, last_coef and significant_coef use a separate context for each
+ // position, so the order doesn't matter, and we don't even have to update their contexts.
+ // in 8x8 blocks, some positions share contexts, so we'll just have to hope that
+ // cabac isn't too sensitive.
+
+ memcpy( nodes_cur[0].cabac_state, &h->cabac.state[ coeff_abs_level_m1_offset[ctx_block_cat] ], 10 );
+
+ for( i = i_last_nnz; i >= b_ac; i-- )
+ {
+ int i_coef = abs_coefs[i];
+ int q = ( f + i_coef * (dc?quant_mf[0]>>1:quant_mf[zigzag[i]]) ) >> 16;
+ int cost_sig[2], cost_last[2];
+ trellis_node_t n;
+
+ // skip 0s: this doesn't affect the output, but saves some unnecessary computation.
+ if( q == 0 )
+ {
+ // no need to calculate ssd of 0s: it's the same in all nodes.
+ // no need to modify level_tree for ctx=0: it starts with an infinite loop of 0s.
+ int sigindex = i_coefs == 64 ? significant_coeff_flag_offset_8x8[b_interlaced][i] : i;
+ const uint32_t cost_sig0 = x264_cabac_size_decision_noup2( &cabac_state_sig[sigindex], 0 )
+ * (uint64_t)i_lambda2 >> ( CABAC_SIZE_BITS - LAMBDA_BITS );
+ for( int j = 1; j < 8; j++ )
+ {
+ if( nodes_cur[j].score != TRELLIS_SCORE_MAX )
+ {
+#define SET_LEVEL(n,l) \
+ level_tree[i_levels_used].abs_level = l; \
+ level_tree[i_levels_used].next = n.level_idx; \
+ n.level_idx = i_levels_used; \
+ i_levels_used++;
+
+ SET_LEVEL( nodes_cur[j], 0 );
+ nodes_cur[j].score += cost_sig0;
+ }
+ }
+ continue;
+ }
+
+ XCHG( trellis_node_t*, nodes_cur, nodes_prev );
+
+ for( int j = 0; j < 8; j++ )
+ nodes_cur[j].score = TRELLIS_SCORE_MAX;
+
+ if( i < i_coefs-1 )
+ {
+ int sigindex = i_coefs == 64 ? significant_coeff_flag_offset_8x8[b_interlaced][i] : i;
+ int lastindex = i_coefs == 64 ? last_coeff_flag_offset_8x8[i] : i;
+ cost_sig[0] = x264_cabac_size_decision_noup2( &cabac_state_sig[sigindex], 0 );
+ cost_sig[1] = x264_cabac_size_decision_noup2( &cabac_state_sig[sigindex], 1 );
+ cost_last[0] = x264_cabac_size_decision_noup2( &cabac_state_last[lastindex], 0 );
+ cost_last[1] = x264_cabac_size_decision_noup2( &cabac_state_last[lastindex], 1 );
+ }
+ else
+ {
+ cost_sig[0] = cost_sig[1] = 0;
+ cost_last[0] = cost_last[1] = 0;
+ }
+
+ // there are a few cases where increasing the coeff magnitude helps,
+ // but it's only around .003 dB, and skipping them ~doubles the speed of trellis.
+ // could also try q-2: that sometimes helps, but also sometimes decimates blocks
+ // that are better left coded, especially at QP > 40.
+ for( int abs_level = q; abs_level >= q-1; abs_level-- )
+ {
+ int unquant_abs_level = (((dc?unquant_mf[0]<<1:unquant_mf[zigzag[i]]) * abs_level + 128) >> 8);
+ int d = i_coef - unquant_abs_level;
+ int64_t ssd;
+ /* Psy trellis: bias in favor of higher AC coefficients in the reconstructed frame. */
+ if( h->mb.i_psy_trellis && i && !dc && !b_chroma )
+ {
+ int orig_coef = (i_coefs == 64) ? h->mb.pic.fenc_dct8[idx][zigzag[i]] : h->mb.pic.fenc_dct4[idx][zigzag[i]];
+ int predicted_coef = orig_coef - i_coef * signs[i];
+ int psy_value = h->mb.i_psy_trellis * abs(predicted_coef + unquant_abs_level * signs[i]);
+ int psy_weight = (i_coefs == 64) ? x264_dct8_weight_tab[zigzag[i]] : x264_dct4_weight_tab[zigzag[i]];
+ ssd = (int64_t)d*d * coef_weight[i] - psy_weight * psy_value;
+ }
+ else
+ /* FIXME: for i16x16 dc is this weight optimal? */
+ ssd = (int64_t)d*d * (dc?256:coef_weight[i]);
+
+ for( int j = 0; j < 8; j++ )
+ {
+ int node_ctx = j;
+ if( nodes_prev[j].score == TRELLIS_SCORE_MAX )
+ continue;
+ n = nodes_prev[j];
+
+ /* code the proposed level, and count how much entropy it would take */
+ if( abs_level || node_ctx )
+ {
+ unsigned f8_bits = cost_sig[ abs_level != 0 ];
+ if( abs_level )
+ {
+ const int i_prefix = X264_MIN( abs_level - 1, 14 );
+ f8_bits += cost_last[ node_ctx == 0 ];
+ f8_bits += x264_cabac_size_decision2( &n.cabac_state[coeff_abs_level1_ctx[node_ctx]], i_prefix > 0 );
+ if( i_prefix > 0 )
+ {
+ uint8_t *ctx = &n.cabac_state[coeff_abs_levelgt1_ctx[node_ctx]];
+ f8_bits += cabac_size_unary[i_prefix][*ctx];
+ *ctx = cabac_transition_unary[i_prefix][*ctx];
+ if( abs_level >= 15 )
+ f8_bits += bs_size_ue_big( abs_level - 15 ) << CABAC_SIZE_BITS;
+ node_ctx = coeff_abs_level_transition[1][node_ctx];
+ }
+ else
+ {
+ f8_bits += 1 << CABAC_SIZE_BITS;
+ node_ctx = coeff_abs_level_transition[0][node_ctx];
+ }
+ }
+ n.score += (uint64_t)f8_bits * i_lambda2 >> ( CABAC_SIZE_BITS - LAMBDA_BITS );
+ }
+
+ if( j || i || dc )
+ n.score += ssd;
+ /* Optimize rounding for DC coefficients in DC-only luma 4x4/8x8 blocks. */
+ else
+ {
+ d = i_coef * signs[0] - ((unquant_abs_level * signs[0] + 8)&~15);
+ n.score += (int64_t)d*d * coef_weight[i];
+ }
+
+ /* save the node if it's better than any existing node with the same cabac ctx */
+ if( n.score < nodes_cur[node_ctx].score )
+ {
+ SET_LEVEL( n, abs_level );
+ nodes_cur[node_ctx] = n;
+ }
+ }
+ }
+ }
+
+ /* output levels from the best path through the trellis */
+ bnode = &nodes_cur[0];
+ for( int j = 1; j < 8; j++ )
+ if( nodes_cur[j].score < bnode->score )
+ bnode = &nodes_cur[j];
+
+ if( bnode == &nodes_cur[0] )
+ {
+ if( i_coefs == 16 && !dc )
+ memset( dct, 0, 16 * sizeof(dctcoef) );
+ return 0;
+ }
+
+ int level = bnode->level_idx;
+ for( i = b_ac; level; i++ )
+ {
+ dct[zigzag[i]] = level_tree[level].abs_level * signs[i];
+ level = level_tree[level].next;
+ }
+ for( ; i < i_coefs; i++ )
+ dct[zigzag[i]] = 0;
+
+ return 1;
+}
+
+/* FIXME: This is a gigantic hack. See below.
+ *
+ * CAVLC is much more difficult to trellis than CABAC.
+ *
+ * CABAC has only three states to track: significance map, last, and the
+ * level state machine.
+ * CAVLC, by comparison, has five: coeff_token (trailing + total),
+ * total_zeroes, zero_run, and the level state machine.
+ *
+ * I know of no paper that has managed to design a close-to-optimal trellis
+ * that covers all five of these and isn't exponential-time. As a result, this
+ * "trellis" isn't: it's just a QNS search. Patches welcome for something better.
+ * It's actually surprisingly fast, albeit not quite optimal. It's pretty close
+ * though; since CAVLC only has 2^16 possible rounding modes (assuming only two
+ * roundings as options), a bruteforce search is feasible. Testing shows
+ * that this QNS is reasonably close to optimal in terms of compression.
+ *
+ * TODO:
+ * Don't bother changing large coefficients when it wouldn't affect bit cost
+ * (e.g. only affecting bypassed suffix bits).
+ * Don't re-run all parts of CAVLC bit cost calculation when not necessary.
+ * e.g. when changing a coefficient from one non-zero value to another in
+ * such a way that trailing ones and suffix length isn't affected. */
+static ALWAYS_INLINE
+int quant_trellis_cavlc( x264_t *h, dctcoef *dct,
+ const udctcoef *quant_mf, const int *unquant_mf,
+ const int *coef_weight, const uint8_t *zigzag,
+ int ctx_block_cat, int i_lambda2, int b_ac,
+ int b_chroma, int dc, int i_coefs, int idx, int b_8x8 )
+{
+ ALIGNED_16( dctcoef quant_coefs[2][16] );
+ ALIGNED_16( dctcoef coefs[16] ) = {0};
+ int delta_distortion[16];
+ int64_t score = 1ULL<<62;
+ int i, j;
+ const int f = 1<<15;
+ int nC = ctx_block_cat == DCT_CHROMA_DC ? 4 : ct_index[x264_mb_predict_non_zero_code( h, ctx_block_cat == DCT_LUMA_DC ? (idx - LUMA_DC)*16 : idx )];
+
+ /* Code for handling 8x8dct -> 4x4dct CAVLC munging. Input/output use a different
+ * step/start/end than internal processing. */
+ int step = 1;
+ int start = b_ac;
+ int end = i_coefs - 1;
+ if( b_8x8 )
+ {
+ start = idx&3;
+ end = 60 + start;
+ step = 4;
+ }
+ idx &= 15;
+
+ i_lambda2 <<= LAMBDA_BITS;
+
+ /* Find last non-zero coefficient. */
+ for( i = end; i >= start; i -= step )
+ if( (unsigned)(dct[zigzag[i]] * (dc?quant_mf[0]>>1:quant_mf[zigzag[i]]) + f-1) >= 2*f )
+ break;
+
+ if( i < start )
+ goto zeroblock;
+
+ /* Prepare for QNS search: calculate distortion caused by each DCT coefficient
+ * rounding to be searched.
+ *
+ * We only search two roundings (nearest and nearest-1) like in CABAC trellis,
+ * so we just store the difference in distortion between them. */
+ int i_last_nnz = b_8x8 ? i >> 2 : i;
+ int coef_mask = 0;
+ int round_mask = 0;
+ for( i = b_ac, j = start; i <= i_last_nnz; i++, j += step )
+ {
+ int coef = dct[zigzag[j]];
+ int abs_coef = abs(coef);
+ int sign = coef < 0 ? -1 : 1;
+ int nearest_quant = ( f + abs_coef * (dc?quant_mf[0]>>1:quant_mf[zigzag[j]]) ) >> 16;
+ quant_coefs[1][i] = quant_coefs[0][i] = sign * nearest_quant;
+ coefs[i] = quant_coefs[1][i];
+ if( nearest_quant )
+ {
+ /* We initialize the trellis with a deadzone halfway between nearest rounding
+ * and always-round-down. This gives much better results than initializing to either
+ * extreme.
+ * FIXME: should we initialize to the deadzones used by deadzone quant? */
+ int deadzone_quant = ( f/2 + abs_coef * (dc?quant_mf[0]>>1:quant_mf[zigzag[j]]) ) >> 16;
+ int unquant1 = (((dc?unquant_mf[0]<<1:unquant_mf[zigzag[j]]) * (nearest_quant-0) + 128) >> 8);
+ int unquant0 = (((dc?unquant_mf[0]<<1:unquant_mf[zigzag[j]]) * (nearest_quant-1) + 128) >> 8);
+ int d1 = abs_coef - unquant1;
+ int d0 = abs_coef - unquant0;
+ delta_distortion[i] = (d0*d0 - d1*d1) * (dc?256:coef_weight[j]);
+
+ /* Psy trellis: bias in favor of higher AC coefficients in the reconstructed frame. */
+ if( h->mb.i_psy_trellis && j && !dc && !b_chroma )
+ {
+ int orig_coef = b_8x8 ? h->mb.pic.fenc_dct8[idx>>2][zigzag[j]] : h->mb.pic.fenc_dct4[idx][zigzag[j]];
+ int predicted_coef = orig_coef - coef;
+ int psy_weight = b_8x8 ? x264_dct8_weight_tab[zigzag[j]] : x264_dct4_weight_tab[zigzag[j]];
+ int psy_value0 = h->mb.i_psy_trellis * abs(predicted_coef + unquant0 * sign);
+ int psy_value1 = h->mb.i_psy_trellis * abs(predicted_coef + unquant1 * sign);
+ delta_distortion[i] += (psy_value0 - psy_value1) * psy_weight;
+ }
+
+ quant_coefs[0][i] = sign * (nearest_quant-1);
+ if( deadzone_quant != nearest_quant )
+ coefs[i] = quant_coefs[0][i];
+ else
+ round_mask |= 1 << i;
+ }
+ else
+ delta_distortion[i] = 0;
+ coef_mask |= (!!coefs[i]) << i;
+ }
+
+ /* Calculate the cost of the starting state. */
+ h->out.bs.i_bits_encoded = 0;
+ if( !coef_mask )
+ bs_write_vlc( &h->out.bs, x264_coeff0_token[nC] );
+ else
+ block_residual_write_cavlc_internal( h, ctx_block_cat, coefs + b_ac, nC );
+ score = (int64_t)h->out.bs.i_bits_encoded * i_lambda2;
+
+ /* QNS loop: pick the change that improves RD the most, apply it, repeat.
+ * coef_mask and round_mask are used to simplify tracking of nonzeroness
+ * and rounding modes chosen. */
+ while( 1 )
+ {
+ int64_t iter_score = score;
+ int iter_distortion_delta = 0;
+ int iter_coef = -1;
+ int iter_mask = coef_mask;
+ int iter_round = round_mask;
+ for( i = b_ac; i <= i_last_nnz; i++ )
+ {
+ if( !delta_distortion[i] )
+ continue;
+
+ /* Set up all the variables for this iteration. */
+ int cur_round = round_mask ^ (1 << i);
+ int round_change = (cur_round >> i)&1;
+ int old_coef = coefs[i];
+ int new_coef = quant_coefs[round_change][i];
+ int cur_mask = (coef_mask&~(1 << i))|(!!new_coef << i);
+ int cur_distortion_delta = delta_distortion[i] * (round_change ? -1 : 1);
+ int64_t cur_score = cur_distortion_delta;
+ coefs[i] = new_coef;
+
+ /* Count up bits. */
+ h->out.bs.i_bits_encoded = 0;
+ if( !cur_mask )
+ bs_write_vlc( &h->out.bs, x264_coeff0_token[nC] );
+ else
+ block_residual_write_cavlc_internal( h, ctx_block_cat, coefs + b_ac, nC );
+ cur_score += (int64_t)h->out.bs.i_bits_encoded * i_lambda2;
+
+ coefs[i] = old_coef;
+ if( cur_score < iter_score )
+ {
+ iter_score = cur_score;
+ iter_coef = i;
+ iter_mask = cur_mask;
+ iter_round = cur_round;
+ iter_distortion_delta = cur_distortion_delta;
+ }
+ }
+ if( iter_coef >= 0 )
+ {
+ score = iter_score - iter_distortion_delta;
+ coef_mask = iter_mask;
+ round_mask = iter_round;
+ coefs[iter_coef] = quant_coefs[((round_mask >> iter_coef)&1)][iter_coef];
+ /* Don't try adjusting coefficients we've already adjusted.
+ * Testing suggests this doesn't hurt results -- and sometimes actually helps. */
+ delta_distortion[iter_coef] = 0;
+ }
+ else
+ break;
+ }
+
+ if( coef_mask )
+ {
+ for( i = b_ac, j = start; i <= i_last_nnz; i++, j += step )
+ dct[zigzag[j]] = coefs[i];
+ for( ; j <= end; j += step )
+ dct[zigzag[j]] = 0;
+ return 1;
+ }
+
+zeroblock:
+ if( !dc )
+ {
+ if( b_8x8 )
+ for( i = start; i <= end; i+=step )
+ dct[zigzag[i]] = 0;
+ else
+ memset( dct, 0, 16*sizeof(dctcoef) );
+ }
+ return 0;
+}
+
+const static uint8_t x264_zigzag_scan2[4] = {0,1,2,3};
+
+int x264_quant_dc_trellis( x264_t *h, dctcoef *dct, int i_quant_cat,
+ int i_qp, int ctx_block_cat, int b_intra, int b_chroma, int idx )
+{
+ if( h->param.b_cabac )
+ return quant_trellis_cabac( h, dct,
+ h->quant4_mf[i_quant_cat][i_qp], h->unquant4_mf[i_quant_cat][i_qp],
+ NULL, ctx_block_cat==DCT_CHROMA_DC ? x264_zigzag_scan2 : x264_zigzag_scan4[MB_INTERLACED],
+ ctx_block_cat, h->mb.i_trellis_lambda2[b_chroma][b_intra], 0, b_chroma, 1, ctx_block_cat==DCT_CHROMA_DC ? 4 : 16, idx );
+
+ if( ctx_block_cat != DCT_CHROMA_DC )
+ ctx_block_cat = DCT_LUMA_DC;
+
+ return quant_trellis_cavlc( h, dct,
+ h->quant4_mf[i_quant_cat][i_qp], h->unquant4_mf[i_quant_cat][i_qp],
+ NULL, ctx_block_cat==DCT_CHROMA_DC ? x264_zigzag_scan2 : x264_zigzag_scan4[MB_INTERLACED],
+ ctx_block_cat, h->mb.i_trellis_lambda2[b_chroma][b_intra], 0, b_chroma, 1, ctx_block_cat==DCT_CHROMA_DC ? 4 : 16, idx, 0 );
+}
+
+int x264_quant_4x4_trellis( x264_t *h, dctcoef *dct, int i_quant_cat,
+ int i_qp, int ctx_block_cat, int b_intra, int b_chroma, int idx )
+{
+ static const uint8_t ctx_ac[14] = {0,1,0,0,1,0,0,1,0,0,0,1,0,0};
+ int b_ac = ctx_ac[ctx_block_cat];
+ if( h->param.b_cabac )
+ return quant_trellis_cabac( h, dct,
+ h->quant4_mf[i_quant_cat][i_qp], h->unquant4_mf[i_quant_cat][i_qp],
+ x264_dct4_weight2_zigzag[MB_INTERLACED],
+ x264_zigzag_scan4[MB_INTERLACED],
+ ctx_block_cat, h->mb.i_trellis_lambda2[b_chroma][b_intra], b_ac, b_chroma, 0, 16, idx );
+
+ return quant_trellis_cavlc( h, dct,
+ h->quant4_mf[i_quant_cat][i_qp], h->unquant4_mf[i_quant_cat][i_qp],
+ x264_dct4_weight2_zigzag[MB_INTERLACED],
+ x264_zigzag_scan4[MB_INTERLACED],
+ ctx_block_cat, h->mb.i_trellis_lambda2[b_chroma][b_intra], b_ac, b_chroma, 0, 16, idx, 0 );
+}
+
+int x264_quant_8x8_trellis( x264_t *h, dctcoef *dct, int i_quant_cat,
+ int i_qp, int ctx_block_cat, int b_intra, int b_chroma, int idx )
+{
+ if( h->param.b_cabac )
+ {
+ return quant_trellis_cabac( h, dct,
+ h->quant8_mf[i_quant_cat][i_qp], h->unquant8_mf[i_quant_cat][i_qp],
+ x264_dct8_weight2_zigzag[MB_INTERLACED],
+ x264_zigzag_scan8[MB_INTERLACED],
+ ctx_block_cat, h->mb.i_trellis_lambda2[b_chroma][b_intra], 0, b_chroma, 0, 64, idx );
+ }
+
+ /* 8x8 CAVLC is split into 4 4x4 blocks */
+ int nzaccum = 0;
+ for( int i = 0; i < 4; i++ )
+ {
+ int nz = quant_trellis_cavlc( h, dct,
+ h->quant8_mf[i_quant_cat][i_qp], h->unquant8_mf[i_quant_cat][i_qp],
+ x264_dct8_weight2_zigzag[MB_INTERLACED],
+ x264_zigzag_scan8[MB_INTERLACED],
+ DCT_LUMA_4x4, h->mb.i_trellis_lambda2[b_chroma][b_intra], 0, b_chroma, 0, 16, idx*4+i, 1 );
+ /* Set up nonzero count for future calls */
+ h->mb.cache.non_zero_count[x264_scan8[idx*4+i]] = nz;
+ nzaccum |= nz;
+ }
+ return nzaccum;
}
projects / x264 / blobdiff