dcadec: skip QMF on unused channels
authorMichael Niedermayer <michaelni@gmx.at>
Mon, 29 Oct 2012 04:21:47 +0000 (05:21 +0100)
committerJustin Ruggles <justin.ruggles@gmail.com>
Tue, 27 Nov 2012 03:50:37 +0000 (22:50 -0500)
When the extra rear channel is present but unused, the
s->channel_order_tab[] value for that channel is -1. The QMF can be
skipped for the extra channel, and doing so avoids an out-of-array read
on s->samples_chanptr[].

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Signed-off-by: Justin Ruggles <justin.ruggles@gmail.com>
libavcodec/dcadec.c

index 712a72aed0352306d56b55ed220774c37ed45a9d..325f3fe96dc8eb9586fcdf21c8acf889e1249862 100644 (file)
@@ -1279,9 +1279,10 @@ static int dca_filter_channels(DCAContext *s, int block_index)
     for (k = 0; k < s->prim_channels; k++) {
 /*        static float pcm_to_double[8] = { 32768.0, 32768.0, 524288.0, 524288.0,
                                             0, 8388608.0, 8388608.0 };*/
-        qmf_32_subbands(s, k, subband_samples[k],
-                        s->samples_chanptr[s->channel_order_tab[k]],
-                        M_SQRT1_2 / 32768.0 /* pcm_to_double[s->source_pcm_res] */);
+        if (s->channel_order_tab[k] >= 0)
+            qmf_32_subbands(s, k, subband_samples[k],
+                            s->samples_chanptr[s->channel_order_tab[k]],
+                            M_SQRT1_2 / 32768.0 /* pcm_to_double[s->source_pcm_res] */);
     }
 
     /* Down mixing */