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/* ------------------------------------------------------------------
* Copyright (C) 1998-2009 PacketVideo
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
* express or implied.
* See the License for the specific language governing permissions
* and limitations under the License.
* -------------------------------------------------------------------
*/
/*
Pathname: PVMP4AudioDecoderConfig
------------------------------------------------------------------------------
REVISION HISTORY
Description: (1) Modified to decode AudioSpecificConfig for any frame number
pVars->bno
(2) Update the input and output descriptions
Description: Eliminated search for ADIF header
Description: Added support for AAC+
Who: Date:
Description:
------------------------------------------------------------------------------
INPUT AND OUTPUT DEFINITIONS
Inputs:
pExt = pointer to the external interface structure. See the file
PVMP4AudioDecoder_API.h for a description of each field.
Data type of pointer to a tPVMP4AudioDecoderExternal
structure.
pExt->pInputBuffer: pointer to input buffer containing input
bitstream
pExt->inputBufferCurrentLength: number of bytes in the input buffer
pExt->inputBufferUsedLength: number of bytes already consumed in
input buffer
pExt->remainderBits: number of bits consumed in addition to
pExt->inputBufferUsedLength
pMem = void pointer to hide the internal implementation of the library
It is cast back to a tDec_Int_File structure. This structure
contains information that needs to persist between calls to
this function, or is too big to be placed on the stack, even
though the data is only needed during execution of this function
Data type void pointer, internally pointer to a tDec_Int_File
structure.
Local Stores/Buffers/Pointers Needed: None
(The memory set aside in pMem performs this task)
Global Stores/Buffers/Pointers Needed: None
Outputs:
status = 0 if no error occurred
MP4AUDEC_NONRECOVERABLE if a non-recoverable error occurred
MP4AUDEC_RECOVERABLE if a recoverable error occurred.
Presently a recoverable error does not exist, but this
was a requirement.
Pointers and Buffers Modified:
pMem contents are modified.
pExt: (more detail in the file PVMP4AudioDecoder_API.h)
inputBufferUsedLength - number of array elements used up by the stream.
remainderBits - remaining bits in the next UInt32 buffer
samplingRate - sampling rate in samples per sec
encodedChannels - channels found on the file (informative)
frameLength - length of the frame
Local Stores Modified: None.
Global Stores Modified: None.
------------------------------------------------------------------------------
FUNCTION DESCRIPTION
------------------------------------------------------------------------------
REQUIREMENTS
PacketVideo Document # CCC-AUD-AAC-ERS-0003
------------------------------------------------------------------------------
REFERENCES
(1) ISO/IEC 14496-3: 1999(E)
subclause 1.6
------------------------------------------------------------------------------
RESOURCES USED
When the code is written for a specific target processor the
the resources used should be documented below.
STACK USAGE: [stack count for this module] + [variable to represent
stack usage for each subroutine called]
where: [stack usage variable] = stack usage for [subroutine
name] (see [filename].ext)
DATA MEMORY USED: x words
PROGRAM MEMORY USED: x words
CLOCK CYCLES: [cycle count equation for this module] + [variable
used to represent cycle count for each subroutine
called]
where: [cycle count variable] = cycle count for [subroutine
name] (see [filename].ext)
------------------------------------------------------------------------------
*/
/*----------------------------------------------------------------------------
; INCLUDES
----------------------------------------------------------------------------*/
#include "pv_audio_type_defs.h"
#include "s_tdec_int_file.h"
#include "ibstream.h" /* where #define INBUF_ARRAY_INDEX_SHIFT */
#include "sfb.h" /* Where samp_rate_info[] is declared */
#include "get_audio_specific_config.h"
#include "pvmp4audiodecoder_api.h" /* Where this function is declared */
/*----------------------------------------------------------------------------
; MACROS
; Define module specific macros here
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; DEFINES
; Include all pre-processor statements here. Include conditional
; compile variables also.
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; LOCAL FUNCTION DEFINITIONS
; Function Prototype declaration
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; LOCAL STORE/BUFFER/POINTER DEFINITIONS
; Variable declaration - defined here and used outside this module
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; EXTERNAL FUNCTION REFERENCES
; Declare functions defined elsewhere and referenced in this module
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES
; Declare variables used in this module but defined elsewhere
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; FUNCTION CODE
----------------------------------------------------------------------------*/
OSCL_EXPORT_REF Int PVMP4AudioDecoderConfig(
tPVMP4AudioDecoderExternal *pExt,
void *pMem)
{
UInt initialUsedBits; /* Unsigned for C55x */
tDec_Int_File *pVars; /* Helper pointer */
Int status = MP4AUDEC_INCOMPLETE_FRAME;
/*
* Initialize "helper" pointers to existing memory.
*/
pVars = (tDec_Int_File *)pMem;
/*
* Translate input buffer variables.
*/
pVars->inputStream.pBuffer = pExt->pInputBuffer;
pVars->inputStream.inputBufferCurrentLength =
(UInt)pExt->inputBufferCurrentLength;
pVars->inputStream.availableBits =
(UInt)(pExt->inputBufferCurrentLength << INBUF_ARRAY_INDEX_SHIFT);
initialUsedBits =
(UInt)((pExt->inputBufferUsedLength << INBUF_ARRAY_INDEX_SHIFT) +
pExt->remainderBits);
pVars->inputStream.usedBits = initialUsedBits;
if (initialUsedBits <= pVars->inputStream.availableBits)
{
/*
* Buffer is not overrun, then
* decode the AudioSpecificConfig() structure
*/
pVars->aacConfigUtilityEnabled = false; /* set aac dec mode */
status = get_audio_specific_config(pVars);
}
byte_align(&pVars->inputStream);
if (status == SUCCESS)
{
pVars->bno++;
/*
* A possible improvement would be to set these values only
* when they change.
*/
pExt->samplingRate =
samp_rate_info[pVars->prog_config.sampling_rate_idx].samp_rate;
/*
* we default to 2 channel, even for mono files, (where channels have same content)
* this is done to ensure support for enhanced aac+ with implicit signalling
*/
pExt->aacPlusEnabled = pVars->aacPlusEnabled;
// pExt->encodedChannels = pVars->mc_info.nch;
pExt->encodedChannels = 2;
pExt->frameLength = pVars->frameLength;
#ifdef AAC_PLUS
pExt->aacPlusUpsamplingFactor = pVars->mc_info.upsamplingFactor;
#endif
}
else
{
/*
* Default to nonrecoverable error status unless there is a Buffer overrun
*/
status = MP4AUDEC_INVALID_FRAME;
if (pVars->inputStream.usedBits > pVars->inputStream.availableBits)
{
/* all bits were used but were not enough to complete parsing */
pVars->inputStream.usedBits = pVars->inputStream.availableBits;
status = MP4AUDEC_INCOMPLETE_FRAME; /* audio config too small */
}
}
/*
* Translate from units of bits back into units of words.
*/
pExt->inputBufferUsedLength =
pVars->inputStream.usedBits >> INBUF_ARRAY_INDEX_SHIFT;
pExt->remainderBits = pVars->inputStream.usedBits & INBUF_BIT_MODULO_MASK;
pVars->status = status;
return (status);
} /* PVMP4AudioDecoderDecodeFrame */
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