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authorDave Burke <daveburke@google.com>2012-04-17 09:51:45 -0700
committerDave Burke <daveburke@google.com>2012-04-17 23:04:43 -0700
commit9bf37cc9712506b2483650c82d3c41152337ef7e (patch)
tree77db44e2bae06e3d144b255628be2b7a55c581d3 /libAACdec/src/aacdec_hcr_bit.cpp
parenta37315fe10ee143d6d0b28c19d41a476a23e63ea (diff)
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Fraunhofer AAC codec.
License boilerplate update to follow. Change-Id: I2810460c11a58b6d148d84673cc031f3685e79b5
Diffstat (limited to 'libAACdec/src/aacdec_hcr_bit.cpp')
-rw-r--r--libAACdec/src/aacdec_hcr_bit.cpp103
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diff --git a/libAACdec/src/aacdec_hcr_bit.cpp b/libAACdec/src/aacdec_hcr_bit.cpp
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+/***************************** MPEG-4 AAC Decoder ***************************
+
+ (C) Copyright Fraunhofer IIS 2000-2008
+ All Rights Reserved
+
+ Please be advised that this software and/or program delivery is
+ Confidential Information of Fraunhofer and subject to and covered by the
+
+ Fraunhofer IIS Software Evaluation Agreement
+ between Google Inc. and Fraunhofer
+ effective and in full force since March 1, 2012.
+
+ You may use this software and/or program only under the terms and
+ conditions described in the above mentioned Fraunhofer IIS Software
+ Evaluation Agreement. Any other and/or further use requires a separate agreement.
+
+
+ $Id$
+ Author(s): Robert Weidner (DSP Solutions)
+ Description: HCR Decoder: Bitstream reading
+
+ This software and/or program is protected by copyright law and international
+ treaties. Any reproduction or distribution of this software and/or program,
+ or any portion of it, may result in severe civil and criminal penalties, and
+ will be prosecuted to the maximum extent possible under law.
+
+*******************************************************************************/
+
+#include "aacdec_hcr_bit.h"
+
+
+/*---------------------------------------------------------------------------------------------
+ description: This function toggles the read direction.
+-----------------------------------------------------------------------------------------------
+ input: current read direction
+-----------------------------------------------------------------------------------------------
+ return: new read direction
+-------------------------------------------------------------------------------------------- */
+UCHAR ToggleReadDirection(UCHAR readDirection)
+{
+ if ( readDirection == FROM_LEFT_TO_RIGHT ) {
+ return FROM_RIGHT_TO_LEFT;
+ }
+ else {
+ return FROM_LEFT_TO_RIGHT;
+ }
+}
+
+
+/*---------------------------------------------------------------------------------------------
+ description: This function returns a bit from the bitstream according to read direction.
+ It is called very often, therefore it makes sense to inline it (runtime).
+-----------------------------------------------------------------------------------------------
+ input: - handle to FDK bitstream
+ - reference value marking start of bitfield
+ - pLeftStartOfSegment
+ - pRightStartOfSegment
+ - readDirection
+-----------------------------------------------------------------------------------------------
+ return: - bit from bitstream
+-------------------------------------------------------------------------------------------- */
+UINT HcrGetABitFromBitstream(HANDLE_FDK_BITSTREAM bs,
+ USHORT *pLeftStartOfSegment,
+ USHORT *pRightStartOfSegment,
+ UCHAR readDirection)
+{
+ UINT bit;
+ INT readBitOffset;
+
+ if (readDirection == FROM_LEFT_TO_RIGHT) {
+ readBitOffset = *pLeftStartOfSegment-FDKgetBitCnt(bs);
+ if( readBitOffset ) {
+ FDKpushBiDirectional(bs, readBitOffset);
+ }
+
+ bit = FDKreadBits(bs, 1);
+
+ *pLeftStartOfSegment += 1;
+ }
+ else {
+ readBitOffset = *pRightStartOfSegment-FDKgetBitCnt(bs);
+ if( readBitOffset ) {
+ FDKpushBiDirectional(bs, readBitOffset);
+ }
+
+ /* to be replaced with a brother function of FDKreadBits() */
+ bit = FDKreadBits(bs, 1);
+ FDKpushBack(bs, 2);
+
+ *pRightStartOfSegment -= 1;
+ }
+
+
+#if ERROR_GENERATOR_BIT_STREAM_HCR
+ static int a;
+ if ((++a % MODULO_DIVISOR_HCR) == 0) {
+ bit = (bit == 0) ? 1 : 0;
+ }
+#endif
+
+ return (bit);
+}
+