commit 34ce250e9075adda4fb8a797c7f47dc049476e8b
author John Grossman <johngro@google.com> Wed Sep 12 14:08:09 2012 -0700
committer John Grossman <johngro@google.com> Wed Sep 12 14:20:05 2012 -0700
tree 1c545f7fbb01b629a9232adb3f3ae66e99c2530e
parent 381d69840ad3af2259f0b7ef49236f9ee9c76b76

Don't zero out spec coeffs before doing the final IMDCT.

Addresses bug 7140347.

When flushing the decoder, you need to make sure to zero out any
lingering spectral coefficients as well as zero out the overlap buffer
state after decoding the final access unit.  Zeroing out the spec
coefficients *before* you decode the last block, however, seems like a
mistake.  If the final block contains any useful information for the
stream, then you end up outputting the overlap portion of the second
to last decoded block combined with zeros.  Because of the shape of
the second to last block's windows, this results in what appears to be
a fade out, but actually is a zero'ed out final block.

Signed-off-by: John Grossman <johngro@google.com>
Change-Id: I0fab9ee1a5899811d5519a91dc05631e9bf4963c

libAACdec/src/aacdecoder.cpp

diff --git a/libAACdec/src/aacdecoder.cpp b/libAACdec/src/aacdecoder.cpp
index 4cf1391..2843e9f 100644
--- a/libAACdec/src/aacdecoder.cpp
+++ b/libAACdec/src/aacdecoder.cpp
@@ -1646,10 +1646,6 @@
               self->sbrEnabled
             );
 
-      if ( flags&AACDEC_FLUSH ) {
-        FDKmemclear(pAacDecoderChannelInfo->pSpectralCoefficient, sizeof(FIXP_DBL)*self->streamInfo.aacSamplesPerFrame);
-      }
-
       switch (pAacDecoderChannelInfo->renderMode)
       {
         case AACDEC_RENDER_IMDCT:
@@ -1677,6 +1673,7 @@
           break;
       }
       if ( flags&AACDEC_FLUSH ) {
+        FDKmemclear(pAacDecoderChannelInfo->pSpectralCoefficient, sizeof(FIXP_DBL)*self->streamInfo.aacSamplesPerFrame);
         FDKmemclear(self->pAacDecoderStaticChannelInfo[c]->pOverlapBuffer, OverlapBufferSize*sizeof(FIXP_DBL));
       }
     }