From 7ba557af6b6cd9839f82855e35f35fe3279c9e05 Mon Sep 17 00:00:00 2001 From: siivonek Date: Tue, 13 Sep 2022 13:27:16 +0300 Subject: [PATCH] [isp] Fix luma cbf writing for ISP splits. Do not write luma cbf if first three splits had luma cbf 0. --- src/encode_coding_tree.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/src/encode_coding_tree.c b/src/encode_coding_tree.c index 0a867bb6..096e4f5c 100644 --- a/src/encode_coding_tree.c +++ b/src/encode_coding_tree.c @@ -622,6 +622,7 @@ static void encode_transform_coeff( lcu_coeff_t* coeff, enum uvg_tree_type tree_type, bool last_split, + bool can_skip_last_cbf, int *luma_cbf_ctx, // Always true except when writing sub partition coeffs (ISP) cu_loc_t *original_loc) // Original dimensions before ISP split { @@ -631,6 +632,8 @@ static void encode_transform_coeff( const int width = cu_loc->width; const int height = cu_loc->height; + bool isp_split = cu_loc->x != original_loc->x || cu_loc->y != original_loc->y; + //const encoder_control_t *const ctrl = state->encoder_control; const videoframe_t * const frame = state->tile->frame; const cu_array_t* used_array = tree_type != UVG_CHROMA_T ? frame->cu_array : frame->chroma_cu_array; @@ -710,7 +713,7 @@ static void encode_transform_coeff( cu_loc_t loc; uvg_cu_loc_ctor(&loc, (x + i * split_width), (y + j * split_height), width >> 1, height >> 1); - encode_transform_coeff(state, &loc, depth + 1, tr_depth + 1, cb_flag_u, cb_flag_v, only_chroma, coeff, tree_type, true, luma_cbf_ctx, &loc); + encode_transform_coeff(state, &loc, depth + 1, tr_depth + 1, cb_flag_u, cb_flag_v, only_chroma, coeff, tree_type, true, false, luma_cbf_ctx, &loc); } } return; @@ -722,11 +725,15 @@ static void encode_transform_coeff( // - we have chroma coefficients at this level // When it is not present, it is inferred to be 1. if ((cur_cu->type == CU_INTRA || tr_depth > 0 || cb_flag_u || cb_flag_v) && !only_chroma && tree_type != UVG_CHROMA_T) { + if (can_skip_last_cbf && isp_split && last_split) { + // Do not write luma cbf if first three isp splits have luma cbf 0 + } else { cabac->cur_ctx = &(cabac->ctx.qt_cbf_model_luma[*luma_cbf_ctx]); CABAC_BIN(cabac, cb_flag_y, "cbf_luma"); if (tr_depth == 0) { *luma_cbf_ctx = 2 + cb_flag_y; } + } } if (cb_flag_y | cb_flag_u | cb_flag_v) { @@ -1621,7 +1628,7 @@ void uvg_encode_coding_tree( // Code (possible) coeffs to bitstream if (cbf) { int luma_cbf_ctx = 0; - encode_transform_coeff(state, &cu_loc, depth, 0, 0, 0, 0, coeff, tree_type, true, &luma_cbf_ctx, &cu_loc); + encode_transform_coeff(state, &cu_loc, depth, 0, 0, 0, 0, coeff, tree_type, true, false, &luma_cbf_ctx, &cu_loc); } encode_mts_idx(state, cabac, cur_cu); @@ -1645,13 +1652,16 @@ void uvg_encode_coding_tree( int split_type = cur_cu->intra.isp_mode; int split_limit = split_type == ISP_MODE_NO_ISP ? 1 : uvg_get_isp_split_num(cu_width, cu_height, split_type); luma_cbf_ctx = split_limit != 1 ? 2 : 0; + // If all first three splits have luma cbf 0, the last one must be one. Since the value ca be derived, no need to write it + bool can_skip_last_cbf = true; for (int i = 0; i < split_limit; ++i) { cu_loc_t split_loc; uvg_get_isp_split_loc(&split_loc, x, y, cu_width, cu_height, i, split_type); // Check if last split to write chroma bool last_split = (i + 1) == split_limit; - encode_transform_coeff(state, &split_loc, depth, 0, 0, 0, 0, coeff, tree_type, last_split, &luma_cbf_ctx, &cu_loc); + encode_transform_coeff(state, &split_loc, depth, 0, 0, 0, 0, coeff, tree_type, last_split, can_skip_last_cbf, &luma_cbf_ctx, &cu_loc); + can_skip_last_cbf &= luma_cbf_ctx == 2; } } @@ -1670,7 +1680,7 @@ void uvg_encode_coding_tree( tmp->violates_lfnst_constrained_luma = false; tmp->violates_lfnst_constrained_chroma = false; tmp->lfnst_last_scan_pos = false; - encode_transform_coeff(state, &cu_loc, depth, 0, 0, 0, 1, coeff, tree_type, true, &luma_cbf_ctx, &cu_loc); + encode_transform_coeff(state, &cu_loc, depth, 0, 0, 0, 1, coeff, tree_type, true, false, &luma_cbf_ctx, &cu_loc); // Write LFNST only once for single tree structure encode_lfnst_idx(state, cabac, tmp, x, y, depth, cu_width, cu_height, tree_type, COLOR_UV); }