From 99609036675ceb968a53397ab3e051e97a7181fd Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Tue, 24 Sep 2002 09:15:46 +0000 Subject: [PATCH] fixing ac prediction encoding with adaptive quantization Originally committed as revision 966 to svn://svn.ffmpeg.org/ffmpeg/trunk --- libavcodec/h263.c | 78 +++++++++++++++++++++++++++++++++++++---------- 1 file changed, 62 insertions(+), 16 deletions(-) diff --git a/libavcodec/h263.c b/libavcodec/h263.c index 1e79d6487f..83f7d96da3 100644 --- a/libavcodec/h263.c +++ b/libavcodec/h263.c @@ -281,22 +281,50 @@ static inline int decide_ac_pred(MpegEncContext * s, DCTELEM block[6][64], int d ac_val = s->ac_val[0][0] + s->block_index[n] * 16; ac_val1= ac_val; if(dir[n]){ + const int xy= s->mb_x + s->mb_y*s->mb_width - s->mb_width; + /* top prediction */ ac_val-= s->block_wrap[n]*16; - for(i=1; i<8; i++){ - const int level= block[n][block_permute_op(i )]; - score0+= ABS(level); - score1+= ABS(level - ac_val[i+8]); - ac_val1[i ]= block[n][block_permute_op(i<<3)]; - ac_val1[i+8]= level; + if(s->mb_y==0 || s->qscale == s->qscale_table[xy] || n==2 || n==3){ + /* same qscale */ + for(i=1; i<8; i++){ + const int level= block[n][block_permute_op(i )]; + score0+= ABS(level); + score1+= ABS(level - ac_val[i+8]); + ac_val1[i ]= block[n][block_permute_op(i<<3)]; + ac_val1[i+8]= level; + } + }else{ + /* different qscale, we must rescale */ + for(i=1; i<8; i++){ + const int level= block[n][block_permute_op(i )]; + score0+= ABS(level); + score1+= ABS(level - ROUNDED_DIV(ac_val[i + 8]*s->qscale_table[xy], s->qscale)); + ac_val1[i ]= block[n][block_permute_op(i<<3)]; + ac_val1[i+8]= level; + } } }else{ + const int xy= s->mb_x-1 + s->mb_y*s->mb_width; + /* left prediction */ ac_val-= 16; - for(i=1; i<8; i++){ - const int level= block[n][block_permute_op(i<<3)]; - score0+= ABS(level); - score1+= ABS(level - ac_val[i]); - ac_val1[i ]= level; - ac_val1[i+8]= block[n][block_permute_op(i )]; + if(s->mb_x==0 || s->qscale == s->qscale_table[xy] || n==1 || n==3){ + /* same qscale */ + for(i=1; i<8; i++){ + const int level= block[n][block_permute_op(i<<3)]; + score0+= ABS(level); + score1+= ABS(level - ac_val[i]); + ac_val1[i ]= level; + ac_val1[i+8]= block[n][block_permute_op(i )]; + } + }else{ + /* different qscale, we must rescale */ + for(i=1; i<8; i++){ + const int level= block[n][block_permute_op(i<<3)]; + score0+= ABS(level); + score1+= ABS(level - ROUNDED_DIV(ac_val[i]*s->qscale_table[xy], s->qscale)); + ac_val1[i ]= level; + ac_val1[i+8]= block[n][block_permute_op(i )]; + } } } } @@ -1678,16 +1706,34 @@ static void mpeg4_inv_pred_ac(MpegEncContext * s, INT16 *block, int n, ac_val = s->ac_val[0][0] + s->block_index[n] * 16; if (dir == 0) { + const int xy= s->mb_x-1 + s->mb_y*s->mb_width; /* left prediction */ ac_val -= 16; - for(i=1;i<8;i++) { - block[block_permute_op(i*8)] -= ac_val[i]; + if(s->mb_x==0 || s->qscale == s->qscale_table[xy] || n==1 || n==3){ + /* same qscale */ + for(i=1;i<8;i++) { + block[block_permute_op(i*8)] -= ac_val[i]; + } + }else{ + /* different qscale, we must rescale */ + for(i=1;i<8;i++) { + block[block_permute_op(i*8)] -= ROUNDED_DIV(ac_val[i]*s->qscale_table[xy], s->qscale); + } } } else { + const int xy= s->mb_x + s->mb_y*s->mb_width - s->mb_width; /* top prediction */ ac_val -= 16 * s->block_wrap[n]; - for(i=1;i<8;i++) { - block[block_permute_op(i)] -= ac_val[i + 8]; + if(s->mb_y==0 || s->qscale == s->qscale_table[xy] || n==2 || n==3){ + /* same qscale */ + for(i=1;i<8;i++) { + block[block_permute_op(i)] -= ac_val[i + 8]; + } + }else{ + /* different qscale, we must rescale */ + for(i=1;i<8;i++) { + block[block_permute_op(i)] -= ROUNDED_DIV(ac_val[i + 8]*s->qscale_table[xy], s->qscale); + } } } }