/*----------------------------------------------------------------------------
*
* File:
* eas_imaadpcm.c
*
* Contents and purpose:
* Implements the IMA ADPCM decoder
*
* Copyright Sonic Network Inc. 2005
* 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.
*
*----------------------------------------------------------------------------
* Revision Control:
* $Revision: 847 $
* $Date: 2007-08-27 21:30:08 -0700 (Mon, 27 Aug 2007) $
*----------------------------------------------------------------------------
*/
#include "eas_data.h"
#include "eas_host.h"
#include "eas_pcm.h"
#include "eas_math.h"
#include "eas_report.h"
// #define _DEBUG_IMA_ADPCM_LOCATE
/*----------------------------------------------------------------------------
* externs
*----------------------------------------------------------------------------
*/
extern const EAS_I16 imaIndexTable[];
extern const EAS_I16 imaStepSizeTable[];
/*----------------------------------------------------------------------------
* prototypes
*----------------------------------------------------------------------------
*/
static EAS_RESULT IMADecoderInit (EAS_DATA_HANDLE pEASData, S_PCM_STATE *pState);
static EAS_RESULT IMADecoderSample (EAS_DATA_HANDLE pEASData, S_PCM_STATE *pState);
static void IMADecoderADPCM (S_DECODER_STATE *pState, EAS_U8 nibble);
static EAS_RESULT IMADecoderLocate (EAS_DATA_HANDLE pEASData, S_PCM_STATE *pState, EAS_I32 time);
/*----------------------------------------------------------------------------
* IMA ADPCM Decoder interface
*----------------------------------------------------------------------------
*/
const S_DECODER_INTERFACE IMADecoder =
{
IMADecoderInit,
IMADecoderSample,
IMADecoderLocate
};
/*----------------------------------------------------------------------------
* IMADecoderInit()
*----------------------------------------------------------------------------
* Purpose:
* Initializes the IMA ADPCM decoder
*
* Inputs:
*
*
* Outputs:
*
*
* Side Effects:
*
*----------------------------------------------------------------------------
*/
/*lint -esym(715, pEASData) common decoder interface - pEASData not used */
static EAS_RESULT IMADecoderInit (EAS_DATA_HANDLE pEASData, S_PCM_STATE *pState)
{
pState->decoderL.step = 0;
pState->decoderR.step = 0;
return EAS_SUCCESS;
}
/*----------------------------------------------------------------------------
* IMADecoderSample()
*----------------------------------------------------------------------------
* Purpose:
* Decodes an IMA ADPCM sample
*
* Inputs:
*
*
* Outputs:
*
*
* Side Effects:
*
*----------------------------------------------------------------------------
*/
static EAS_RESULT IMADecoderSample (EAS_DATA_HANDLE pEASData, S_PCM_STATE *pState)
{
EAS_RESULT result;
EAS_I16 sTemp;
/* if high nibble, decode */
if (pState->hiNibble)
{
IMADecoderADPCM(&pState->decoderL, (EAS_U8)(pState->srcByte >> 4));
pState->hiNibble = EAS_FALSE;
}
/* low nibble, need to fetch another byte */
else
{
/* check for loop */
if ((pState->bytesLeft == 0) && (pState->loopSamples != 0))
{
/* seek to start of loop */
if ((result = EAS_HWFileSeek(pEASData->hwInstData, pState->fileHandle, (EAS_I32) (pState->startPos + pState->loopLocation))) != EAS_SUCCESS)
return result;
pState->bytesLeft = pState->byteCount = (EAS_I32) pState->bytesLeftLoop;
pState->blockCount = 0;
pState->flags &= ~PCM_FLAGS_EMPTY;
{ /* dpp: EAS_ReportEx(_EAS_SEVERITY_DETAIL, "IMADecoderSample: Rewind file to %d, bytesLeft = %d\n", pState->startPos, pState->bytesLeft); */ }
}
/* if start of block, fetch new predictor and step index */
if ((pState->blockSize != 0) && (pState->blockCount == 0) && (pState->bytesLeft != 0))
{
/* get predicted sample for left channel */
if ((result = EAS_HWGetWord(pEASData->hwInstData, pState->fileHandle, &sTemp, EAS_FALSE)) != EAS_SUCCESS)
return result;
#ifdef _DEBUG_IMA_ADPCM
{ /* dpp: EAS_ReportEx(_EAS_SEVERITY_DETAIL, "Predictor: Was %d, now %d\n", pState->decoderL.acc, sTemp); */ }
#endif
pState->decoderL.acc = pState->decoderL.x1 = sTemp;
/* get step index for left channel - upper 8 bits are reserved */
if ((result = EAS_HWGetWord(pEASData->hwInstData, pState->fileHandle, &sTemp, EAS_FALSE)) != EAS_SUCCESS)
return result;
#ifdef _DEBUG_IMA_ADPCM
{ /* dpp: EAS_ReportEx(_EAS_SEVERITY_DETAIL, "Step: Was %d, now %d\n", pState->decoderL.step, sTemp); */ }
#endif
pState->decoderL.step = sTemp & 0xff;
if (pState->flags & PCM_FLAGS_STEREO)
{
/* get predicted sample for right channel */
if ((result = EAS_HWGetWord(pEASData->hwInstData, pState->fileHandle, &sTemp, EAS_FALSE)) != EAS_SUCCESS)
return result;
pState->decoderR.acc = pState->decoderR.x1 = sTemp;
/* get step index for right channel - upper 8 bits are reserved */
if ((result = EAS_HWGetWord(pEASData->hwInstData, pState->fileHandle, &sTemp, EAS_FALSE)) != EAS_SUCCESS)
return result;
#ifdef _DEBUG_IMA_ADPCM
{ /* dpp: EAS_ReportEx(_EAS_SEVERITY_DETAIL, "Step: Was %d, now %d\n", pState->decoderR.step, sTemp); */ }
#endif
pState->decoderR.step = sTemp & 0xff;
pState->blockCount = pState->blockSize - 8;
pState->bytesLeft -= 8;
}
else
{
pState->blockCount = pState->blockSize - 4;
pState->bytesLeft -= 4;
}
}
else
{
/* get another ADPCM data pair */
if (pState->bytesLeft)
{
if ((result = EAS_HWGetByte(pEASData->hwInstData, pState->fileHandle, &pState->srcByte)) != EAS_SUCCESS)
return result;
/* decode the low nibble */
pState->bytesLeft--;
pState->blockCount--;
IMADecoderADPCM(&pState->decoderL, (EAS_U8)(pState->srcByte & 0x0f));
if (pState->flags & PCM_FLAGS_STEREO)
IMADecoderADPCM(&pState->decoderR, (EAS_U8)(pState->srcByte >> 4));
else
pState->hiNibble = EAS_TRUE;
}
/* out of ADPCM data, generate enough samples to fill buffer */
else
{
pState->decoderL.x1 = pState->decoderL.x0;
pState->decoderR.x1 = pState->decoderR.x0;
}
}
}
return EAS_SUCCESS;
}
/*----------------------------------------------------------------------------
* IMADecoderADPCM()
*----------------------------------------------------------------------------
* Purpose:
* Decodes an IMA ADPCM sample
*
* Inputs:
*
*
* Outputs:
*
*
* Side Effects:
*
*----------------------------------------------------------------------------
*/
static void IMADecoderADPCM (S_DECODER_STATE *pState, EAS_U8 nibble)
{
EAS_INT delta;
EAS_INT stepSize;
/* get stepsize from table */
stepSize = imaStepSizeTable[pState->step];
/* delta = (abs(delta) + 0.5) * step / 4 */
delta = 0;
if (nibble & 4)
delta += stepSize;
if (nibble & 2)
/*lint -e{702} use shift for performance */
delta += stepSize >> 1;
if (nibble & 1)
/*lint -e{702} use shift for performance */
delta += stepSize >> 2;
/*lint -e{702} use shift for performance */
delta += stepSize >> 3;
/* integrate the delta */
if (nibble & 8)
pState->acc -= delta;
else
pState->acc += delta;
/* saturate */
if (pState->acc > 32767)
pState->acc = 32767;
if (pState->acc < -32768)
pState->acc = -32768;
pState->x1 = (EAS_PCM) pState->acc;
/* compute new step size */
pState->step += imaIndexTable[nibble];
if (pState->step < 0)
pState->step = 0;
if (pState->step > 88)
pState->step = 88;
#ifdef _DEBUG_IMA_ADPCM
{ /* dpp: EAS_ReportEx(_EAS_SEVERITY_DETAIL, "In=%u, Pred=%d, Step=%d\n", nibble, pState->acc, imaStepSizeTable[pState->step]); */ }
#endif
}
/*----------------------------------------------------------------------------
* IMADecoderLocate()
*----------------------------------------------------------------------------
* Locate in an IMA ADPCM stream
*----------------------------------------------------------------------------
*/
static EAS_RESULT IMADecoderLocate (EAS_DATA_HANDLE pEASData, S_PCM_STATE *pState, EAS_I32 time)
{
EAS_RESULT result;
EAS_I32 temp;
EAS_I32 samplesPerBlock;
EAS_I32 secs, msecs;
/* no need to calculate if time is zero */
if (time == 0)
temp = 0;
/* not zero */
else
{
/* can't seek if not a blocked file */
if (pState->blockSize == 0)
return EAS_ERROR_FEATURE_NOT_AVAILABLE;
/* calculate number of samples per block */
if (pState->flags & PCM_FLAGS_STEREO)
samplesPerBlock = pState->blockSize - 7;
else
samplesPerBlock = (pState->blockSize << 1) - 7;
/* break down into secs and msecs */
secs = time / 1000;
msecs = time - (secs * 1000);
/* calculate sample number fraction from msecs */
temp = (msecs * pState->sampleRate);
temp = (temp >> 10) + ((temp * 49) >> 21);
/* add integer sample count */
temp += secs * pState->sampleRate;
#ifdef _DEBUG_IMA_ADPCM_LOCATE
EAS_ReportEx(_EAS_SEVERITY_NOFILTER, 0x2380b977, 0x00000006 , time, temp);
#endif
/* for looped samples, calculate position in the loop */
if ((temp > pState->byteCount) && (pState->loopSamples != 0))
{
EAS_I32 numBlocks;
EAS_I32 samplesPerLoop;
EAS_I32 samplesInLastBlock;
numBlocks = (EAS_I32) (pState->loopStart / pState->blockSize);
samplesInLastBlock = (EAS_I32) pState->loopStart - (numBlocks * pState->blockSize);
if (samplesInLastBlock)
{
if (pState->flags & PCM_FLAGS_STEREO)
samplesInLastBlock = samplesInLastBlock - 7;
else
/*lint -e{703} use shift for performance */
samplesInLastBlock = (samplesInLastBlock << 1) - 7;
}
samplesPerLoop = numBlocks * samplesPerBlock + samplesInLastBlock;
temp = temp % samplesPerLoop;
#ifdef _DEBUG_IMA_ADPCM_LOCATE
EAS_ReportEx(_EAS_SEVERITY_NOFILTER, 0x2380b977, 0x00000007 , numBlocks, samplesPerLoop, samplesInLastBlock, temp);
#endif
}
/* find start of block for requested sample */
temp = (temp / samplesPerBlock) * pState->blockSize;
#ifdef _DEBUG_IMA_ADPCM_LOCATE
EAS_ReportEx(_EAS_SEVERITY_NOFILTER, 0x2380b977, 0x00000008 , temp);
#endif
}
/* seek to new location */
if ((result = EAS_PESeek(pEASData, pState, &temp)) != EAS_SUCCESS)
return result;
#ifdef _DEBUG_IMA_ADPCM_LOCATE
EAS_ReportEx(_EAS_SEVERITY_NOFILTER, 0x2380b977, 0x00000009 , pState->bytesLeft);
#endif
/* reset state */
pState->blockCount = 0;
pState->hiNibble = EAS_FALSE;
if ((pState->state != EAS_STATE_PAUSING) && (pState->state != EAS_STATE_PAUSED))
pState->state = EAS_STATE_READY;
return EAS_SUCCESS;
}