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avcodec/x86/idctdsp_init: Fix IDCT permutation for 32bit without SSE2

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bfb28b5ce8 removed the MMX idct_put
and idct_add functions, because they were overridden by SSE2 versions
(which use SSE2 only for the put/add part, not the actual IDCT).
This meant that for MMX, the idct functions are not set in unison,
so that the permutation which is meant to apply to all three
is incorrect on 32bit systems if SSE2 is unavailable/disabled.

Fix this by setting the MMX version only if SSE2 is enabled.

(No one complained, so apparently no one uses a new FFmpeg
with non-SSE2 capable systems.)

Reviewed-by: Lynne <dev@lynne.ee>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
This commit is contained in:
Andreas Rheinhardt
2025-11-04 13:56:01 +01:00
parent d4e0d5ed48
commit 86f8adc58e
1 changed files with 1 additions and 12 deletions
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13
libavcodec/x86/idctdsp_init.c
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@@ -65,18 +65,6 @@ av_cold void ff_idctdsp_init_x86(IDCTDSPContext *c, AVCodecContext *avctx,
{
int cpu_flags = av_get_cpu_flags();
#if ARCH_X86_32
if (EXTERNAL_MMX(cpu_flags)) {
if (!high_bit_depth &&
avctx->lowres == 0 &&
(avctx->idct_algo == FF_IDCT_AUTO ||
avctx->idct_algo == FF_IDCT_SIMPLEAUTO ||
avctx->idct_algo == FF_IDCT_SIMPLEMMX)) {
c->idct = ff_simple_idct_mmx;
}
}
#endif
if (EXTERNAL_SSE2(cpu_flags)) {
c->put_signed_pixels_clamped = ff_put_signed_pixels_clamped_sse2;
c->put_pixels_clamped = ff_put_pixels_clamped_sse2;
@@ -88,6 +76,7 @@ av_cold void ff_idctdsp_init_x86(IDCTDSPContext *c, AVCodecContext *avctx,
(avctx->idct_algo == FF_IDCT_AUTO ||
avctx->idct_algo == FF_IDCT_SIMPLEAUTO ||
avctx->idct_algo == FF_IDCT_SIMPLEMMX)) {
c->idct = ff_simple_idct_mmx;
c->idct_put = ff_simple_idct_put_sse2;
c->idct_add = ff_simple_idct_add_sse2;
c->perm_type = FF_IDCT_PERM_SIMPLE;