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author | Michael Niedermayer <michaelni@gmx.at> | 2004-05-05 00:14:22 +0000 |
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committer | Michael Niedermayer <michaelni@gmx.at> | 2004-05-05 00:14:22 +0000 |
commit | a7137a0452e0c821f4ad1232875c7065097187b0 (patch) | |
tree | 203bbf8945f782b65c7a697633c33d229fdb2586 | |
parent | 4c263142c5da89745fb956b3c5738f257c873532 (diff) | |
download | ffmpeg-a7137a0452e0c821f4ad1232875c7065097187b0.tar.gz |
mpeg4 dc prediction simplification
dc cliping fix
Originally committed as revision 3107 to svn://svn.ffmpeg.org/ffmpeg/trunk
-rw-r--r-- | libavcodec/h263.c | 82 |
1 files changed, 31 insertions, 51 deletions
diff --git a/libavcodec/h263.c b/libavcodec/h263.c index c1113f5bd2..8cb9d5646c 100644 --- a/libavcodec/h263.c +++ b/libavcodec/h263.c @@ -76,7 +76,7 @@ static void mpeg4_encode_visual_object_header(MpegEncContext * s); static void mpeg4_encode_vol_header(MpegEncContext * s, int vo_number, int vol_number); #endif //CONFIG_ENCODERS static void mpeg4_decode_sprite_trajectory(MpegEncContext * s, GetBitContext *gb); -static inline int ff_mpeg4_pred_dc(MpegEncContext * s, int n, uint16_t **dc_val_ptr, int *dir_ptr); +static inline int ff_mpeg4_pred_dc(MpegEncContext * s, int n, int level, int *dir_ptr, int encoding); #ifdef CONFIG_ENCODERS static uint8_t uni_DCtab_lum_len[512]; @@ -1073,15 +1073,7 @@ void mpeg4_encode_mb(MpegEncContext * s, int i; for(i=0; i<6; i++){ - const int level= block[i][0]; - uint16_t *dc_ptr; - - dc_diff[i]= level - ff_mpeg4_pred_dc(s, i, &dc_ptr, &dir[i]); - if (i < 4) { - *dc_ptr = level * s->y_dc_scale; - } else { - *dc_ptr = level * s->c_dc_scale; - } + dc_diff[i]= ff_mpeg4_pred_dc(s, i, block[i][0], &dir[i], 1); } if(s->flags & CODEC_FLAG_AC_PRED){ @@ -2382,14 +2374,14 @@ void ff_set_qscale(MpegEncContext * s, int qscale) /** * predicts the dc. + * encoding quantized level -> quantized diff + * decoding quantized diff -> quantized level * @param n block index (0-3 are luma, 4-5 are chroma) - * @param dc_val_ptr a pointer to the dc_val entry for the current MB will be stored here * @param dir_ptr pointer to an integer where the prediction direction will be stored - * @return the quantized predicted dc */ -static inline int ff_mpeg4_pred_dc(MpegEncContext * s, int n, uint16_t **dc_val_ptr, int *dir_ptr) +static inline int ff_mpeg4_pred_dc(MpegEncContext * s, int n, int level, int *dir_ptr, int encoding) { - int a, b, c, wrap, pred, scale; + int a, b, c, wrap, pred, scale, ret; uint16_t *dc_val; /* find prediction */ @@ -2431,10 +2423,27 @@ static inline int ff_mpeg4_pred_dc(MpegEncContext * s, int n, uint16_t **dc_val_ /* we assume pred is positive */ pred = FASTDIV((pred + (scale >> 1)), scale); - /* prepare address for prediction update */ - *dc_val_ptr = &dc_val[0]; + if(encoding){ + ret = level - pred; + }else{ + level += pred; + ret= level; + if(s->error_resilience>=3){ + if(level<0){ + av_log(s->avctx, AV_LOG_ERROR, "dc<0 at %dx%d\n", s->mb_x, s->mb_y); + return -1; + } + if(level*scale > 2048 + scale){ + av_log(s->avctx, AV_LOG_ERROR, "dc overflow at %dx%d\n", s->mb_x, s->mb_y); + return -1; + } + } + } + level *=scale; + if(level&(~2047)) level= level<0 ? 0 : 2047; + dc_val[0]= level; - return pred; + return ret; } /** @@ -4537,8 +4546,7 @@ not_coded: */ static inline int mpeg4_decode_dc(MpegEncContext * s, int n, int *dir_ptr) { - int level, pred, code; - uint16_t *dc_val; + int level, code; if (n < 4) code = get_vlc2(&s->gb, dc_lum.table, DC_VLC_BITS, 1); @@ -4573,30 +4581,8 @@ static inline int mpeg4_decode_dc(MpegEncContext * s, int n, int *dir_ptr) } } } - pred = ff_mpeg4_pred_dc(s, n, &dc_val, dir_ptr); - level += pred; - if (level < 0){ - if(s->error_resilience>=3){ - av_log(s->avctx, AV_LOG_ERROR, "dc<0 at %dx%d\n", s->mb_x, s->mb_y); - return -1; - } - level = 0; - } - if (n < 4) { - *dc_val = level * s->y_dc_scale; - } else { - *dc_val = level * s->c_dc_scale; - } - if(IS_3IV1) - *dc_val = level * 8; - - if(s->error_resilience>=3){ - if(*dc_val > 2048 + s->y_dc_scale + s->c_dc_scale){ - av_log(s->avctx, AV_LOG_ERROR, "dc overflow at %dx%d\n", s->mb_x, s->mb_y); - return -1; - } - } - return level; + + return ff_mpeg4_pred_dc(s, n, level, dir_ptr, 0); } /** @@ -4842,14 +4828,8 @@ static inline int mpeg4_decode_block(MpegEncContext * s, DCTELEM * block, not_coded: if (intra) { if(s->qscale >= s->intra_dc_threshold){ - uint16_t *dc_val; - block[0] += ff_mpeg4_pred_dc(s, n, &dc_val, &dc_pred_dir); - if (n < 4) { - *dc_val = block[0] * s->y_dc_scale; - } else { - *dc_val = block[0] * s->c_dc_scale; - } - + block[0] = ff_mpeg4_pred_dc(s, n, block[0], &dc_pred_dir, 0); + if(i == -1) i=0; } |