Stowage/ffmpeg
2
0
Fork 0
mirror of https://git.ffmpeg.org/ffmpeg.git synced 2025-12-08 06:09:50 +00:00
Code Issues Projects Releases Packages Wiki Activity

VP8: much faster DC transform handling

Browse source 
A lot of the time the DC block is empty: don't do the WHT in this case.
A lot of the rest of the time, there's only one coefficient: make a special
DC-only transform for that case.
When the block is empty, don't incorrectly mark luma DCT blocks as having DC
coefficients.

Originally committed as revision 24670 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Jason Garrett-Glaser 2010-08-02 20:57:03 +00:00
parent c934562c12
commit f311208cf1
3 changed files with 29 additions and 8 deletions
Download patch file Download diff file Expand all files Collapse all files

21
libavcodec/vp8dsp.c
View file

@ -51,13 +51,25 @@ static void vp8_luma_dc_wht_c(DCTELEM block[4][4][16], DCTELEM dc[16])
dc[i*4+2] = 0;
dc[i*4+3] = 0;
*block[i][0] = (t0 + t1) >> 3;
*block[i][1] = (t3 + t2) >> 3;
*block[i][2] = (t0 - t1) >> 3;
*block[i][3] = (t3 - t2) >> 3;
block[i][0][0] = (t0 + t1) >> 3;
block[i][1][0] = (t3 + t2) >> 3;
block[i][2][0] = (t0 - t1) >> 3;
block[i][3][0] = (t3 - t2) >> 3;
}
}
static void vp8_luma_dc_wht_dc_c(DCTELEM block[4][4][16], DCTELEM dc[16])
{
int i, val = (dc[0] + 3) >> 3;
dc[0] = 0;
for (i = 0; i < 4; i++) {
block[i][0][0] = val;
block[i][1][0] = val;
block[i][2][0] = val;
block[i][3][0] = val;
}
}
#define MUL_20091(a) ((((a)*20091) >> 16) + (a))
#define MUL_35468(a) (((a)*35468) >> 16)
@ -480,6 +492,7 @@ VP8_BILINEAR(4)
av_cold void ff_vp8dsp_init(VP8DSPContext *dsp)
{
dsp->vp8_luma_dc_wht = vp8_luma_dc_wht_c;
dsp->vp8_luma_dc_wht_dc = vp8_luma_dc_wht_dc_c;
dsp->vp8_idct_add = vp8_idct_add_c;
dsp->vp8_idct_dc_add = vp8_idct_dc_add_c;
dsp->vp8_idct_dc_add4y = vp8_idct_dc_add4y_c;