Revert input buffer count for the SoftAAC* decoders back to 4.

This improves the netflix bandwidth change responsiveness.
With the old count of 32 the audio decoder running at a higher
priority would starve the video decoder for about 1 sec while
draining the input data.

I haven't been able to break any stream playback using MediaCodec
using the lower count, even though I'm sure I had a good reason
to increase it in the first place (see bug 6478823)

Change-Id: I7fd3e71794b0cc1570ea9d27d1d869ab1e1750c4
related-to-bug: 6685031
diff --git a/media/libstagefright/codecs/aacdec/SoftAAC.h b/media/libstagefright/codecs/aacdec/SoftAAC.h
index c0789ab..2e75005 100644
--- a/media/libstagefright/codecs/aacdec/SoftAAC.h
+++ b/media/libstagefright/codecs/aacdec/SoftAAC.h
@@ -45,7 +45,7 @@
 
 private:
     enum {
-        kNumInputBuffers        = 32,
+        kNumInputBuffers        = 4,
         kNumOutputBuffers       = 4,
     };
 
diff --git a/media/libstagefright/codecs/aacdec/SoftAAC2.h b/media/libstagefright/codecs/aacdec/SoftAAC2.h
index ac379f4..0353196 100644
--- a/media/libstagefright/codecs/aacdec/SoftAAC2.h
+++ b/media/libstagefright/codecs/aacdec/SoftAAC2.h
@@ -44,7 +44,7 @@
 
 private:
     enum {
-        kNumInputBuffers        = 32,
+        kNumInputBuffers        = 4,
         kNumOutputBuffers       = 4,
     };