ppc: fix usage of dsp_mask

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/ppc/dsputil_ppc.c

@@ -146,6 +146,14 @@ static void prefetch_ppc(void *mem, int stride, int h)
 void dsputil_init_ppc(DSPContext* c, AVCodecContext *avctx)
 {
     const int high_bit_depth = avctx->bits_per_raw_sample > 8;
+    int mm_flags = av_get_cpu_flags();
+
+    if (avctx->dsp_mask) {
+        if (avctx->dsp_mask & AV_CPU_FLAG_FORCE)
+            mm_flags |= (avctx->dsp_mask & 0xffff);
+        else
+            mm_flags &= ~(avctx->dsp_mask & 0xffff);
+    }
 
     // Common optimizations whether AltiVec is available or not
     c->prefetch = prefetch_ppc;
@@ -165,7 +173,7 @@ void dsputil_init_ppc(DSPContext* c, AVCodecContext *avctx)
 #if HAVE_ALTIVEC
     if(CONFIG_H264_DECODER) dsputil_h264_init_ppc(c, avctx);
 
-    if (av_get_cpu_flags() & AV_CPU_FLAG_ALTIVEC) {
+    if (mm_flags & AV_CPU_FLAG_ALTIVEC) {
         dsputil_init_altivec(c, avctx);
         float_init_altivec(c, avctx);
         int_init_altivec(c, avctx);