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New previous coef context experiment

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Adds an experiment to derive the previous context of a coefficient
not just from the previous coefficient in the scan order but from a
combination of several neighboring coefficients previously encountered
in scan order.  A precomputed table of neighbors for each location
for each scan type and block size is used. Currently 5 neighbors are
used.

Results are about 0.2% positive using a strategy where the max coef
magnitude from the 5 neigbors is used to derive the context.

Change-Id: Ie708b54d8e1898af742846ce2d1e2b0d89fd4ad5
This commit is contained in:
Deb Mukherjee
2012-11-27 15:51:06 -08:00
parent de52948665
commit 08f0c7cc9c
8 changed files with 325 additions and 32 deletions
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54
vp9/encoder/vp9_rdopt.c
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@@ -513,29 +513,48 @@ int vp9_uvsse(MACROBLOCK *x) {
}
#if CONFIG_NEWCOEFCONTEXT
#define PT pn
#else
#define PT pt
#endif
static int cost_coeffs_2x2(MACROBLOCK *mb,
BLOCKD *b, PLANE_TYPE type,
ENTROPY_CONTEXT *a, ENTROPY_CONTEXT *l) {
int c = (type == PLANE_TYPE_Y_NO_DC); /* start at coef 0, unless Y with Y2 */
int nodc = (type == PLANE_TYPE_Y_NO_DC);
int c = nodc; /* start at coef 0, unless Y with Y2 */
int eob = b->eob;
int pt; /* surrounding block/prev coef predictor */
int cost = 0;
int16_t *qcoeff_ptr = b->qcoeff;
#if CONFIG_NEWCOEFCONTEXT
const int *neighbors = vp9_default_zig_zag1d_4x4_neighbors;
int pn;
#endif
VP9_COMBINEENTROPYCONTEXTS(pt, *a, *l);
assert(eob <= 4);
#if CONFIG_NEWCOEFCONTEXT
pn = pt;
#endif
for (; c < eob; c++) {
int v = qcoeff_ptr[vp9_default_zig_zag1d_4x4[c]];
int t = vp9_dct_value_tokens_ptr[v].Token;
cost += mb->token_costs[TX_8X8][type][vp9_coef_bands_4x4[c]][pt][t];
cost += vp9_dct_value_cost_ptr[v];
pt = vp9_prev_token_class[t];
#if CONFIG_NEWCOEFCONTEXT
if (c < 4 - 1)
pn = vp9_get_coef_neighbor_context(
qcoeff_ptr, nodc, neighbors, vp9_default_zig_zag1d_4x4[c + 1]);
#endif
}
if (c < 4)
cost += mb->token_costs[TX_8X8][type][vp9_coef_bands_4x4[c]]
[pt] [DCT_EOB_TOKEN];
[PT][DCT_EOB_TOKEN];
// is eob first coefficient;
pt = (c > !type);
*a = *l = pt;
@@ -546,7 +565,8 @@ static int cost_coeffs(MACROBLOCK *mb, BLOCKD *b, PLANE_TYPE type,
ENTROPY_CONTEXT *a, ENTROPY_CONTEXT *l,
TX_SIZE tx_size) {
const int eob = b->eob;
int c = (type == PLANE_TYPE_Y_NO_DC); /* start at coef 0, unless Y with Y2 */
int nodc = (type == PLANE_TYPE_Y_NO_DC);
int c = nodc; /* start at coef 0, unless Y with Y2 */
int cost = 0, default_eob, seg_eob;
int pt; /* surrounding block/prev coef predictor */
int const *scan, *band;
@@ -555,6 +575,10 @@ static int cost_coeffs(MACROBLOCK *mb, BLOCKD *b, PLANE_TYPE type,
MB_MODE_INFO *mbmi = &mb->e_mbd.mode_info_context->mbmi;
TX_TYPE tx_type = DCT_DCT;
int segment_id = mbmi->segment_id;
#if CONFIG_NEWCOEFCONTEXT
const int *neighbors;
int pn;
#endif
scan = vp9_default_zig_zag1d_4x4;
band = vp9_coef_bands_4x4;
default_eob = 16;
@@ -628,17 +652,28 @@ static int cost_coeffs(MACROBLOCK *mb, BLOCKD *b, PLANE_TYPE type,
VP9_COMBINEENTROPYCONTEXTS(pt, *a, *l);
#if CONFIG_NEWCOEFCONTEXT
neighbors = vp9_get_coef_neighbors_handle(scan);
pn = pt;
#endif
if (tx_type != DCT_DCT) {
for (; c < eob; c++) {
int v = qcoeff_ptr[scan[c]];
int t = vp9_dct_value_tokens_ptr[v].Token;
cost += mb->hybrid_token_costs[tx_size][type][band[c]][pt][t];
cost += mb->hybrid_token_costs[tx_size][type][band[c]][PT][t];
cost += vp9_dct_value_cost_ptr[v];
pt = vp9_prev_token_class[t];
#if CONFIG_NEWCOEFCONTEXT
if (c < seg_eob - 1 && NEWCOEFCONTEXT_BAND_COND(band[c + 1]))
pn = vp9_get_coef_neighbor_context(
qcoeff_ptr, nodc, neighbors, scan[c + 1]);
else
pn = pt;
#endif
}
if (c < seg_eob)
cost += mb->hybrid_token_costs[tx_size][type][band[c]]
[pt][DCT_EOB_TOKEN];
[PT][DCT_EOB_TOKEN];
} else {
for (; c < eob; c++) {
int v = qcoeff_ptr[scan[c]];
@@ -646,10 +681,17 @@ static int cost_coeffs(MACROBLOCK *mb, BLOCKD *b, PLANE_TYPE type,
cost += mb->token_costs[tx_size][type][band[c]][pt][t];
cost += vp9_dct_value_cost_ptr[v];
pt = vp9_prev_token_class[t];
#if CONFIG_NEWCOEFCONTEXT
if (c < seg_eob - 1 && NEWCOEFCONTEXT_BAND_COND(band[c + 1]))
pn = vp9_get_coef_neighbor_context(
qcoeff_ptr, nodc, neighbors, scan[c + 1]);
else
pn = pt;
#endif
}
if (c < seg_eob)
cost += mb->token_costs[tx_size][type][band[c]]
[pt][DCT_EOB_TOKEN];
[PT][DCT_EOB_TOKEN];
}
// is eob first coefficient;