RepoMirrors/ffmpeg
1
0
Fork 0
mirror of https://git.ffmpeg.org/ffmpeg.git synced 2024-12-18 21:45:10 +00:00
Code Issues Projects Releases Wiki Activity

x86: simple_idct: 12bits versions

Browse Source 
On 12 frames of a 444p 12 bits DNxHR sequence, _put function:
C:         78902 decicycles in idct,  262071 runs,     73 skips
avx:       32478 decicycles in idct,  262045 runs,     99 skips

Difference between the 2:
stddev:    0.39 PSNR:104.47 MAXDIFF:    2

This is unavoidable and due to the scale factors used in the x86
version, which cannot match the C ones.

In addition, the trick of adding an initial bias to the input of a
pass can overflow, as the input coefficients are already 15bits,
which is the maximum this function can handle.

Overall, however, the omse on 12 bits samples goes from 0.16916 to
0.16883. Reducing rowshift by 1 improves to 0.0908, but causes
overflows.

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Christophe Gisquet 2015-10-12 19:37:49 +02:00 committed by Michael Niedermayer
parent 4369b9dc7b
commit 7ece8b50b1
3 changed files with 42 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
libavcodec/x86/idctdsp_init.c
View File

@ -86,8 +86,8 @@ av_cold void ff_idctdsp_init_x86(IDCTDSPContext *c, AVCodecContext *avctx,
c->add_pixels_clamped = ff_add_pixels_clamped_sse2;
}
if (ARCH_X86_64 &&
avctx->bits_per_raw_sample == 10 && avctx->lowres == 0 &&
if (ARCH_X86_64 && avctx->lowres == 0) {
if (avctx->bits_per_raw_sample == 10 &&
(avctx->idct_algo == FF_IDCT_AUTO ||
avctx->idct_algo == FF_IDCT_SIMPLEAUTO ||
avctx->idct_algo == FF_IDCT_SIMPLE)) {
@ -104,5 +104,23 @@ av_cold void ff_idctdsp_init_x86(IDCTDSPContext *c, AVCodecContext *avctx,
c->idct = ff_simple_idct10_avx;
c->perm_type = FF_IDCT_PERM_TRANSPOSE;
}
}
if (avctx->bits_per_raw_sample == 12 &&
(avctx->idct_algo == FF_IDCT_AUTO ||
avctx->idct_algo == FF_IDCT_SIMPLEMMX)) {
if (EXTERNAL_SSE2(cpu_flags)) {
c->idct_put = ff_simple_idct12_put_sse2;
c->idct_add = NULL;
c->idct = ff_simple_idct12_sse2;
c->perm_type = FF_IDCT_PERM_TRANSPOSE;
}
if (EXTERNAL_AVX(cpu_flags)) {
c->idct_put = ff_simple_idct12_put_avx;
c->idct_add = NULL;
c->idct = ff_simple_idct12_avx;
c->perm_type = FF_IDCT_PERM_TRANSPOSE;
}
}
}
}

6
libavcodec/x86/simple_idct.h
View File

@ -31,4 +31,10 @@ void ff_simple_idct10_avx(int16_t *block);
void ff_simple_idct10_put_sse2(uint8_t *dest, int line_size, int16_t *block);
void ff_simple_idct10_put_avx(uint8_t *dest, int line_size, int16_t *block);
void ff_simple_idct12_sse2(int16_t *block);
void ff_simple_idct12_avx(int16_t *block);
void ff_simple_idct12_put_sse2(uint8_t *dest, int line_size, int16_t *block);
void ff_simple_idct12_put_avx(uint8_t *dest, int line_size, int16_t *block);
#endif /* AVCODEC_X86_SIMPLE_IDCT_H */

16
libavcodec/x86/simple_idct10.asm
View File

@ -29,9 +29,12 @@
SECTION_RODATA
cextern pw_2
cextern pw_16
cextern pw_1023
cextern pw_4095
pd_round_12: times 4 dd 1<<(12-1)
pd_round_15: times 4 dd 1<<(15-1)
pd_round_19: times 4 dd 1<<(19-1)
%include "libavcodec/x86/simple_idct10_template.asm"
@ -46,6 +49,19 @@ cglobal simple_idct10, 1, 1, 16
cglobal simple_idct10_put, 3, 3, 16
IDCT_FN "", 12, "", 19, 0, pw_1023
RET
cglobal simple_idct12, 1, 1, 16
; coeffs are already 15bits, adding the offset would cause
; overflow in the input
IDCT_FN "", 15, pw_2, 16
RET
cglobal simple_idct12_put, 3, 3, 16
; range isn't known, so the C simple_idct range is used
; Also, using a bias on input overflows, so use the bias
; on output of the first butterfly instead
IDCT_FN "", 15, pw_2, 16, 0, pw_4095
RET
%endmacro
INIT_XMM sse2