xvididct: Ensure that the scantable permutation is always set correctly

This fixes cases where the scantable permuation would get overwritten by
the general idctdsp initialization.

libavcodec/x86/idctdsp_init.c

@@ -37,6 +37,8 @@ static const uint8_t simple_mmx_permutation[64] = {
     0x32, 0x3A, 0x36, 0x3B, 0x33, 0x3E, 0x37, 0x3F,
 };
 
+static const uint8_t idct_sse2_row_perm[8] = { 0, 4, 1, 5, 2, 6, 3, 7 };
+
 av_cold int ff_init_scantable_permutation_x86(uint8_t *idct_permutation,
                                               enum idct_permutation_type perm_type)
 {
@@ -47,6 +49,10 @@ av_cold int ff_init_scantable_permutation_x86(uint8_t *idct_permutation,
         for (i = 0; i < 64; i++)
             idct_permutation[i] = simple_mmx_permutation[i];
         return 1;
+    case FF_IDCT_PERM_SSE2:
+        for (i = 0; i < 64; i++)
+            idct_permutation[i] = (i & 0x38) | idct_sse2_row_perm[i & 7];
+        return 1;
     }
 
     return 0;

libavcodec/x86/xvididct_init.c

@@ -25,17 +25,6 @@
 #include "idct_xvid.h"
 #include "idctdsp.h"
 
-static const uint8_t idct_sse2_row_perm[8] = { 0, 4, 1, 5, 2, 6, 3, 7 };
-
-static av_cold void init_scantable_permutation_sse2(uint8_t *idct_permutation,
-                                                    enum idct_permutation_type perm_type)
-{
-    int i;
-
-    for (i = 0; i < 64; i++)
-        idct_permutation[i] = (i & 0x38) | idct_sse2_row_perm[i & 7];
-}
-
 av_cold void ff_xvididct_init_x86(IDCTDSPContext *c)
 {
     int cpu_flags = av_get_cpu_flags();
@@ -44,12 +33,14 @@ av_cold void ff_xvididct_init_x86(IDCTDSPContext *c)
         c->idct_put  = ff_idct_xvid_mmx_put;
         c->idct_add  = ff_idct_xvid_mmx_add;
         c->idct      = ff_idct_xvid_mmx;
+        c->perm_type = FF_IDCT_PERM_NONE;
     }
 
     if (INLINE_MMXEXT(cpu_flags)) {
         c->idct_put  = ff_idct_xvid_mmxext_put;
         c->idct_add  = ff_idct_xvid_mmxext_add;
         c->idct      = ff_idct_xvid_mmxext;
+        c->perm_type = FF_IDCT_PERM_NONE;
     }
 
     if (INLINE_SSE2(cpu_flags)) {
@@ -57,7 +48,5 @@ av_cold void ff_xvididct_init_x86(IDCTDSPContext *c)
         c->idct_add  = ff_idct_xvid_sse2_add;
         c->idct      = ff_idct_xvid_sse2;
         c->perm_type = FF_IDCT_PERM_SSE2;
-
-        init_scantable_permutation_sse2(c->idct_permutation, c->perm_type);
     }
 }

libavcodec/xvididct.c

@@ -33,4 +33,6 @@ av_cold void ff_xvididct_init(IDCTDSPContext *c, AVCodecContext *avctx)
 
     if (ARCH_X86)
         ff_xvididct_init_x86(c);
+
+    ff_init_scantable_permutation(c->idct_permutation, c->perm_type);
 }