diff options
Diffstat (limited to 'libavcodec/dv.c')
| -rw-r--r-- | libavcodec/dv.c | 22 |
1 files changed, 18 insertions, 4 deletions
diff --git a/libavcodec/dv.c b/libavcodec/dv.c index f132217ee5..824679f6dd 100644 --- a/libavcodec/dv.c +++ b/libavcodec/dv.c @@ -253,6 +253,7 @@ static int dvvideo_init(AVCodecContext *avctx) typedef struct BlockInfo { const uint8_t *shift_table; const uint8_t *scan_table; + const int *iweight_table; uint8_t pos; /* position in block */ uint8_t dct_mode; uint8_t partial_bit_count; @@ -295,6 +296,7 @@ static void dv_decode_ac(GetBitContext *gb, BlockInfo *mb, DCTELEM *block) int last_index = get_bits_size(gb); const uint8_t *scan_table = mb->scan_table; const uint8_t *shift_table = mb->shift_table; + const int *iweight_table = mb->iweight_table; int pos = mb->pos; int partial_bit_count = mb->partial_bit_count; int level, pos1, run, vlc_len, index; @@ -343,7 +345,12 @@ static void dv_decode_ac(GetBitContext *gb, BlockInfo *mb, DCTELEM *block) break; pos1 = scan_table[pos]; - block[pos1] = level << shift_table[pos1]; + level <<= shift_table[pos1]; + + /* unweigh, round, and shift down */ + level = (level*iweight_table[pos] + (1 << (dv_iweight_bits-1))) >> dv_iweight_bits; + + block[pos1] = level; UPDATE_CACHE(re, gb); } @@ -409,6 +416,7 @@ static inline void dv_decode_video_segment(DVVideoContext *s, dct_mode = get_bits1(&gb); mb->dct_mode = dct_mode; mb->scan_table = s->dv_zigzag[dct_mode]; + mb->iweight_table = dct_mode ? dv_iweight_248 : dv_iweight_88; class1 = get_bits(&gb, 2); mb->shift_table = s->dv_idct_shift[class1 == 3][dct_mode] [quant + dv_quant_offset[class1]]; @@ -647,7 +655,7 @@ static always_inline PutBitContext* dv_encode_ac(EncBlockInfo* bi, PutBitContext } static always_inline void dv_set_class_number(DCTELEM* blk, EncBlockInfo* bi, - const uint8_t* zigzag_scan, int bias) + const uint8_t* zigzag_scan, const int *weight, int bias) { int i, area; static const int classes[] = {12, 24, 36, 0xffff}; @@ -664,7 +672,11 @@ static always_inline void dv_set_class_number(DCTELEM* blk, EncBlockInfo* bi, if (level+15 > 30U) { bi->sign[i] = (level>>31)&1; - bi->mb[i] = level= ABS(level)>>4; + /* weigh it and and shift down into range, adding for rounding */ + /* the extra division by a factor of 2^4 reverses the 8x expansion of the DCT + AND the 2x doubling of the weights */ + level = (ABS(level) * weight[i] + (1<<(dv_weight_bits+3))) >> (dv_weight_bits+4); + bi->mb[i] = level; if(level>max) max= level; bi->bit_size[area] += dv_rl2vlc_size(i - prev - 1, level); bi->next[prev]= i; @@ -875,7 +887,9 @@ static inline void dv_encode_video_segment(DVVideoContext *s, s->fdct[enc_blk->dct_mode](block); dv_set_class_number(block, enc_blk, - enc_blk->dct_mode ? ff_zigzag248_direct : ff_zigzag_direct, j/4); + enc_blk->dct_mode ? ff_zigzag248_direct : ff_zigzag_direct, + enc_blk->dct_mode ? dv_weight_248 : dv_weight_88, + j/4); init_put_bits(pb, ptr, block_sizes[j]/8); put_bits(pb, 9, (uint16_t)(((enc_blk->mb[0] >> 3) - 1024 + 2) >> 2)); |