MP3Extractor and MP3 decoder fixes - DO NOT MERGE

cherry-picked the following patches from HC branch:
o PV's mp3 decoder mistreated inputBufferCurrentLength in unit of bytes as in unit of bits
o Do not enforce the rule in MP3Extractor that all audio frames in an mp3 file must have the same mode
o When the temp buffer wraps around, the next read position should start
    from what have been read to avoid reading the same remaining bytes in
    the buffer again.
o Speed up MP3Extractor using cached reads

bug - 4083532

Change-Id: I7bbd2bd358fd5ee322287866cb8ee0c2bb217fea

1 files changed, 4 insertions, 2 deletions

diff --git a/media/libstagefright/codecs/mp3dec/src/pvmp3_decode_header.cpp b/media/libstagefright/codecs/mp3dec/src/pvmp3_decode_header.cpp
index 8b0250a..d443b7c 100644
--- a/media/libstagefright/codecs/mp3dec/src/pvmp3_decode_header.cpp
+++ b/media/libstagefright/codecs/mp3dec/src/pvmp3_decode_header.cpp
@@ -121,9 +121,11 @@ ERROR_CODE pvmp3_decode_header(tmp3Bits  *inputStream,
     uint32  temp;
 
     /*
-     *  Verify that at least the header is complete
+     * Verify that at least the header is complete
+     * Note that SYNC_WORD_LNGTH is in unit of bits, but inputBufferCurrentLength
+     * is in unit of bytes.
      */
-    if (inputStream->inputBufferCurrentLength < (SYNC_WORD_LNGTH + 21))
+    if (inputStream->inputBufferCurrentLength < ((SYNC_WORD_LNGTH + 21) >> 3))
     {
         return NO_ENOUGH_MAIN_DATA_ERROR;
     }