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Rewrite intra prediction mode coding to be simpler.

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Should work exactly the same, but with the prediction mode selection done
separately from the binarization it's easier to see that the implementation
is correct.
This commit is contained in:
Ari Koivula 2013-12-18 12:48:20 +02:00
parent cf0d314d03
commit 553bcdc324
1 changed files with 33 additions and 30 deletions
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63
src/encoder.c
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@ -1241,41 +1241,44 @@ void encode_coding_tree(encoder_control *encoder, uint16_t x_ctb,
CABAC_BINS_EP(&cabac, tmp_pred, 5, "rem_intra_luma_pred_mode");
}
// Chroma intra prediction
/** Table 9-35 – Binarization for intra_chroma_pred_mode
* intra_chroma_pred_mode bin_string
* 4 0
* 0 100
* 1 101
* 2 110
* 3 111
*/
cabac.ctx = &g_chroma_pred_model[0];
CABAC_BIN(&cabac, ((intra_pred_mode_chroma != 36) ? 1 : 0), "intra_chroma_pred_mode");
{ // start intra chroma pred mode coding
unsigned pred_mode = 5;
unsigned chroma_pred_modes[4] = {0, 26, 10, 1};
// If not copied from luma, signal it
if (intra_pred_mode_chroma != 36) {
int8_t tmp_pred = intra_pred_mode_chroma;
// Default chroma predictors
uint32_t allowed_chroma_dir[5] = { 0, 26, 10, 1, 36 };
// If intra is the same as one of the default predictors, replace it
for (i = 0; i < 4; i++) {
if (intra_pred_mode == allowed_chroma_dir[i]) {
allowed_chroma_dir[i] = 34; // VER+8 mode
break;
if (intra_pred_mode_chroma == 36) {
pred_mode = 4;
} else if (intra_pred_mode_chroma == 34) {
// Angular 34 mode is possible only if intra pred mode is one of the
// possible chroma pred modes, in which case it is signaled with that
// duplicate mode.
for (i = 0; i < 4; ++i) {
if (intra_pred_mode == chroma_pred_modes[i]) pred_mode = i;
}
} else {
for (i = 0; i < 4; ++i) {
if (intra_pred_mode_chroma == chroma_pred_modes[i]) pred_mode = i;
}
}
for (i = 0; i < 4; i++) {
if (tmp_pred == allowed_chroma_dir[i]) {
tmp_pred = i;
break;
}
/**
* Table 9-35 – Binarization for intra_chroma_pred_mode
* intra_chroma_pred_mode bin_string
* 4 0
* 0 100
* 1 101
* 2 110
* 3 111
* Table 9-37 - Assignment of ctxInc to syntax elements with context coded bins
* intra_chroma_pred_mode[][] = 0, bypass, bypass
*/
cabac.ctx = &g_chroma_pred_model[0];
if (pred_mode == 4) {
CABAC_BIN(&cabac, 0, "intra_chroma_pred_mode");
} else {
CABAC_BIN(&cabac, 1, "intra_chroma_pred_mode");
CABAC_BINS_EP(&cabac, pred_mode, 2, "intra_chroma_pred_mode");
}
CABAC_BINS_EP(&cabac, tmp_pred, 2, "intra_chroma_pred_mode");
}
} // end intra chroma pred mode coding
encode_transform_coeff(encoder, x_ctb, y_ctb, depth, 0, 0, 0);
}