From d557838cfbf1e010447de742829e8a2f27d7b67c Mon Sep 17 00:00:00 2001 From: Roman Shaposhnik Date: Mon, 11 Aug 2008 09:35:58 +0000 Subject: [PATCH] Coalescing the un-weighting and de-quantization steps for faster processing Originally committed as revision 14691 to svn://svn.ffmpeg.org/ffmpeg/trunk --- libavcodec/dv.c | 49 +++++++++++++++++++------------------------------ libavcodec/dvdata.h | 23 +---------------------- 2 files changed, 20 insertions(+), 52 deletions(-) diff --git a/libavcodec/dv.c b/libavcodec/dv.c index 8ba952a..c324038 100644 --- a/libavcodec/dv.c +++ b/libavcodec/dv.c @@ -50,7 +50,7 @@ typedef struct DVVideoContext { uint8_t *buf; uint8_t dv_zigzag[2][64]; - uint8_t dv_idct_shift[2][2][22][64]; + uint32_t dv_idct_factor[2][2][22][64]; void (*get_pixels)(DCTELEM *block, const uint8_t *pixels, int line_size); void (*fdct[2])(DCTELEM *block); @@ -84,25 +84,22 @@ static struct dv_vlc_pair { static void dv_build_unquantize_tables(DVVideoContext *s, uint8_t* perm) { - int i, q, j; + int i, q, a; /* NOTE: max left shift is 6 */ for(q = 0; q < 22; q++) { /* 88DCT */ - for(i = 1; i < 64; i++) { - /* 88 table */ - j = perm[i]; - s->dv_idct_shift[0][0][q][j] = - dv_quant_shifts[q][dv_88_areas[i]] + 1; - s->dv_idct_shift[1][0][q][j] = s->dv_idct_shift[0][0][q][j] + 1; - } - - /* 248DCT */ - for(i = 1; i < 64; i++) { - /* 248 table */ - s->dv_idct_shift[0][1][q][i] = - dv_quant_shifts[q][dv_248_areas[i]] + 1; - s->dv_idct_shift[1][1][q][i] = s->dv_idct_shift[0][1][q][i] + 1; + i=1; + for(a = 0; a<4; a++) { + for(; i < dv_quant_areas[a]; i++) { + /* 88 table */ + s->dv_idct_factor[0][0][q][i] = dv_iweight_88[i]<<(dv_quant_shifts[q][a] + 1); + s->dv_idct_factor[1][0][q][i] = s->dv_idct_factor[0][0][q][i]<<1; + + /* 248 table */ + s->dv_idct_factor[0][1][q][i] = dv_iweight_248[i]<<(dv_quant_shifts[q][a] + 1); + s->dv_idct_factor[1][1][q][i] = s->dv_idct_factor[0][1][q][i]<<1; + } } } } @@ -247,9 +244,8 @@ static av_cold int dvvideo_init(AVCodecContext *avctx) // #define printf(...) av_log(NULL, AV_LOG_ERROR, __VA_ARGS__) typedef struct BlockInfo { - const uint8_t *shift_table; + const uint32_t *factor_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; @@ -281,11 +277,10 @@ static void dv_decode_ac(GetBitContext *gb, BlockInfo *mb, DCTELEM *block) { int last_index = gb->size_in_bits; const uint8_t *scan_table = mb->scan_table; - const uint8_t *shift_table = mb->shift_table; - const int *iweight_table = mb->iweight_table; + const uint32_t *factor_table = mb->factor_table; int pos = mb->pos; int partial_bit_count = mb->partial_bit_count; - int level, pos1, run, vlc_len, index; + int level, run, vlc_len, index; OPEN_READER(re, gb); UPDATE_CACHE(re, gb); @@ -330,13 +325,8 @@ static void dv_decode_ac(GetBitContext *gb, BlockInfo *mb, DCTELEM *block) if (pos >= 64) break; - pos1 = scan_table[pos]; - 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; + level = (level*factor_table[pos] + (1 << (dv_iweight_bits-1))) >> dv_iweight_bits; + block[scan_table[pos]] = level; UPDATE_CACHE(re, gb); } @@ -402,9 +392,8 @@ 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] + mb->factor_table = s->dv_idct_factor[class1 == 3][dct_mode] [quant + dv_quant_offset[class1]]; dc = dc << 2; /* convert to unsigned because 128 is not added in the diff --git a/libavcodec/dvdata.h b/libavcodec/dvdata.h index 7d8f19d..29260bf 100644 --- a/libavcodec/dvdata.h +++ b/libavcodec/dvdata.h @@ -286,28 +286,6 @@ static const uint8_t dv_vlc_level[409] = { }; /* unquant tables (not used directly) */ -static const uint8_t dv_88_areas[64] = { - 0,0,0,1,1,1,2,2, - 0,0,1,1,1,2,2,2, - 0,1,1,1,2,2,2,3, - 1,1,1,2,2,2,3,3, - 1,1,2,2,2,3,3,3, - 1,2,2,2,3,3,3,3, - 2,2,2,3,3,3,3,3, - 2,2,3,3,3,3,3,3, -}; - -static const uint8_t dv_248_areas[64] = { - 0,0,1,1,1,2,2,3, - 0,0,1,1,2,2,2,3, - 0,1,1,2,2,2,3,3, - 0,1,1,2,2,2,3,3, - 1,1,2,2,2,3,3,3, - 1,1,2,2,2,3,3,3, - 1,2,2,2,3,3,3,3, - 1,2,2,3,3,3,3,3, -}; - static const uint8_t dv_quant_shifts[22][4] = { { 3,3,4,4 }, { 3,3,4,4 }, @@ -334,6 +312,7 @@ static const uint8_t dv_quant_shifts[22][4] = { }; static const uint8_t dv_quant_offset[4] = { 6, 3, 0, 1 }; +static const uint8_t dv_quant_areas[4] = { 6, 21, 43, 64 }; /* NOTE: I prefer hardcoding the positioning of dv blocks, it is simpler :-) */ -- 2.7.4