eas_imaadpcm.c revision 56c99cd2c2c1e6ab038dac5fced5b92ccf11ff6c 
1/*----------------------------------------------------------------------------
2 *
3 * File:
4 * eas_imaadpcm.c
5 *
6 * Contents and purpose:
7 * Implements the IMA ADPCM decoder
8 *
9 * Copyright Sonic Network Inc. 2005
10
11 * Licensed under the Apache License, Version 2.0 (the "License");
12 * you may not use this file except in compliance with the License.
13 * You may obtain a copy of the License at
14 *
15 *      http://www.apache.org/licenses/LICENSE-2.0
16 *
17 * Unless required by applicable law or agreed to in writing, software
18 * distributed under the License is distributed on an "AS IS" BASIS,
19 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
20 * See the License for the specific language governing permissions and
21 * limitations under the License.
22 *
23 *----------------------------------------------------------------------------
24 * Revision Control:
25 *   $Revision: 847 $
26 *   $Date: 2007-08-27 21:30:08 -0700 (Mon, 27 Aug 2007) $
27 *----------------------------------------------------------------------------
28*/
29
30#include "eas_data.h"
31#include "eas_host.h"
32#include "eas_pcm.h"
33#include "eas_math.h"
34#include "eas_report.h"
35
36// #define _DEBUG_IMA_ADPCM_LOCATE
37
38/*----------------------------------------------------------------------------
39 * externs
40 *----------------------------------------------------------------------------
41*/
42extern const EAS_I16 imaIndexTable[];
43extern const EAS_I16 imaStepSizeTable[];
44
45/*----------------------------------------------------------------------------
46 * prototypes
47 *----------------------------------------------------------------------------
48*/
49static EAS_RESULT IMADecoderInit (EAS_DATA_HANDLE pEASData, S_PCM_STATE *pState);
50static EAS_RESULT IMADecoderSample (EAS_DATA_HANDLE pEASData, S_PCM_STATE *pState);
51static void IMADecoderADPCM (S_DECODER_STATE *pState, EAS_U8 nibble);
52static EAS_RESULT IMADecoderLocate (EAS_DATA_HANDLE pEASData, S_PCM_STATE *pState, EAS_I32 time);
53
54/*----------------------------------------------------------------------------
55 * IMA ADPCM Decoder interface
56 *----------------------------------------------------------------------------
57*/
58const S_DECODER_INTERFACE IMADecoder =
59{
60    IMADecoderInit,
61    IMADecoderSample,
62    IMADecoderLocate
63};
64
65/*----------------------------------------------------------------------------
66 * IMADecoderInit()
67 *----------------------------------------------------------------------------
68 * Purpose:
69 * Initializes the IMA ADPCM decoder
70 *
71 * Inputs:
72 *
73 *
74 * Outputs:
75 *
76 *
77 * Side Effects:
78 *
79 *----------------------------------------------------------------------------
80*/
81/*lint -esym(715, pEASData) common decoder interface - pEASData not used */
82static EAS_RESULT IMADecoderInit (EAS_DATA_HANDLE pEASData, S_PCM_STATE *pState)
83{
84    pState->decoderL.step = 0;
85    pState->decoderR.step = 0;
86    return EAS_SUCCESS;
87}
88
89/*----------------------------------------------------------------------------
90 * IMADecoderSample()
91 *----------------------------------------------------------------------------
92 * Purpose:
93 * Decodes an IMA ADPCM sample
94 *
95 * Inputs:
96 *
97 *
98 * Outputs:
99 *
100 *
101 * Side Effects:
102 *
103 *----------------------------------------------------------------------------
104*/
105static EAS_RESULT IMADecoderSample (EAS_DATA_HANDLE pEASData, S_PCM_STATE *pState)
106{
107    EAS_RESULT result;
108    EAS_I16 sTemp;
109
110    /* if high nibble, decode */
111    if (pState->hiNibble)
112    {
113        IMADecoderADPCM(&pState->decoderL, (EAS_U8)(pState->srcByte >> 4));
114        pState->hiNibble = EAS_FALSE;
115    }
116
117    /* low nibble, need to fetch another byte */
118    else
119    {
120        /* check for loop */
121        if ((pState->bytesLeft == 0) && (pState->loopSamples != 0))
122        {
123            /* seek to start of loop */
124            if ((result = EAS_HWFileSeek(pEASData->hwInstData, pState->fileHandle, (EAS_I32) (pState->startPos + pState->loopLocation))) != EAS_SUCCESS)
125                return result;
126            pState->bytesLeft = pState->byteCount = (EAS_I32) pState->bytesLeftLoop;
127            pState->blockCount = 0;
128            pState->flags &= ~PCM_FLAGS_EMPTY;
129            { /* dpp: EAS_ReportEx(_EAS_SEVERITY_DETAIL, "IMADecoderSample: Rewind file to %d, bytesLeft = %d\n", pState->startPos, pState->bytesLeft); */ }
130        }
131
132        /* if start of block, fetch new predictor and step index */
133        if ((pState->blockSize != 0) && (pState->blockCount == 0) && (pState->bytesLeft != 0))
134        {
135
136            /* get predicted sample for left channel */
137            if ((result = EAS_HWGetWord(pEASData->hwInstData, pState->fileHandle, &sTemp, EAS_FALSE)) != EAS_SUCCESS)
138                return result;
139#ifdef _DEBUG_IMA_ADPCM
140            { /* dpp: EAS_ReportEx(_EAS_SEVERITY_DETAIL, "Predictor: Was %d, now %d\n", pState->decoderL.acc, sTemp); */ }
141#endif
142            pState->decoderL.acc = pState->decoderL.x1 = sTemp;
143
144            /* get step index for left channel - upper 8 bits are reserved */
145            if ((result = EAS_HWGetWord(pEASData->hwInstData, pState->fileHandle, &sTemp, EAS_FALSE)) != EAS_SUCCESS)
146                return result;
147#ifdef _DEBUG_IMA_ADPCM
148            { /* dpp: EAS_ReportEx(_EAS_SEVERITY_DETAIL, "Step: Was %d, now %d\n", pState->decoderL.step, sTemp); */ }
149#endif
150            pState->decoderL.step = sTemp & 0xff;
151
152            if (pState->flags & PCM_FLAGS_STEREO)
153            {
154                /* get predicted sample for right channel */
155                if ((result = EAS_HWGetWord(pEASData->hwInstData, pState->fileHandle, &sTemp, EAS_FALSE)) != EAS_SUCCESS)
156                    return result;
157                pState->decoderR.acc = pState->decoderR.x1 = sTemp;
158
159                /* get step index for right channel - upper 8 bits are reserved */
160                if ((result = EAS_HWGetWord(pEASData->hwInstData, pState->fileHandle, &sTemp, EAS_FALSE)) != EAS_SUCCESS)
161                    return result;
162#ifdef _DEBUG_IMA_ADPCM
163                { /* dpp: EAS_ReportEx(_EAS_SEVERITY_DETAIL, "Step: Was %d, now %d\n", pState->decoderR.step, sTemp); */ }
164#endif
165                pState->decoderR.step = sTemp & 0xff;
166
167                pState->blockCount = pState->blockSize - 8;
168                pState->bytesLeft -= 8;
169            }
170            else
171            {
172                pState->blockCount = pState->blockSize - 4;
173                pState->bytesLeft -= 4;
174            }
175        }
176        else
177        {
178
179            /* get another ADPCM data pair */
180            if (pState->bytesLeft)
181            {
182
183                if ((result = EAS_HWGetByte(pEASData->hwInstData, pState->fileHandle, &pState->srcByte)) != EAS_SUCCESS)
184                    return result;
185
186                /* decode the low nibble */
187                pState->bytesLeft--;
188                pState->blockCount--;
189                IMADecoderADPCM(&pState->decoderL, (EAS_U8)(pState->srcByte & 0x0f));
190
191                if (pState->flags & PCM_FLAGS_STEREO)
192                    IMADecoderADPCM(&pState->decoderR, (EAS_U8)(pState->srcByte >> 4));
193                else
194                    pState->hiNibble = EAS_TRUE;
195            }
196
197            /* out of ADPCM data, generate enough samples to fill buffer */
198            else
199            {
200                pState->decoderL.x1 = pState->decoderL.x0;
201                pState->decoderR.x1 = pState->decoderR.x0;
202            }
203        }
204    }
205
206    return EAS_SUCCESS;
207}
208
209/*----------------------------------------------------------------------------
210 * IMADecoderADPCM()
211 *----------------------------------------------------------------------------
212 * Purpose:
213 * Decodes an IMA ADPCM sample
214 *
215 * Inputs:
216 *
217 *
218 * Outputs:
219 *
220 *
221 * Side Effects:
222 *
223 *----------------------------------------------------------------------------
224*/
225static void IMADecoderADPCM (S_DECODER_STATE *pState, EAS_U8 nibble)
226{
227    EAS_INT delta;
228    EAS_INT stepSize;
229
230    /* get stepsize from table */
231    stepSize = imaStepSizeTable[pState->step];
232
233    /* delta = (abs(delta) + 0.5) * step / 4 */
234    delta = 0;
235    if (nibble & 4)
236        delta += stepSize;
237
238    if (nibble & 2)
239        /*lint -e{702} use shift for performance */
240        delta += stepSize >> 1;
241
242    if (nibble & 1)
243        /*lint -e{702} use shift for performance */
244        delta += stepSize >> 2;
245
246    /*lint -e{702} use shift for performance */
247    delta += stepSize >> 3;
248
249    /* integrate the delta */
250    if (nibble & 8)
251      pState->acc -= delta;
252    else
253      pState->acc += delta;
254
255    /* saturate */
256    if (pState->acc > 32767)
257        pState->acc = 32767;
258    if (pState->acc < -32768)
259        pState->acc = -32768;
260    pState->x1 = (EAS_PCM) pState->acc;
261
262    /* compute new step size */
263    pState->step += imaIndexTable[nibble];
264    if (pState->step < 0)
265        pState->step = 0;
266    if (pState->step > 88)
267        pState->step = 88;
268
269#ifdef _DEBUG_IMA_ADPCM
270    { /* dpp: EAS_ReportEx(_EAS_SEVERITY_DETAIL, "In=%u, Pred=%d, Step=%d\n", nibble, pState->acc,  imaStepSizeTable[pState->step]); */ }
271#endif
272}
273
274/*----------------------------------------------------------------------------
275 * IMADecoderLocate()
276 *----------------------------------------------------------------------------
277 * Locate in an IMA ADPCM stream
278 *----------------------------------------------------------------------------
279*/
280static EAS_RESULT IMADecoderLocate (EAS_DATA_HANDLE pEASData, S_PCM_STATE *pState, EAS_I32 time)
281{
282    EAS_RESULT result;
283    EAS_I32 temp;
284    EAS_I32 samplesPerBlock;
285    EAS_I32 secs, msecs;
286
287    /* no need to calculate if time is zero */
288    if (time == 0)
289        temp = 0;
290
291    /* not zero */
292    else
293    {
294
295        /* can't seek if not a blocked file */
296        if (pState->blockSize == 0)
297            return EAS_ERROR_FEATURE_NOT_AVAILABLE;
298
299        /* calculate number of samples per block */
300        if (pState->flags & PCM_FLAGS_STEREO)
301            samplesPerBlock = pState->blockSize - 7;
302        else
303            samplesPerBlock = (pState->blockSize << 1) - 7;
304
305        /* break down into secs and msecs */
306        secs = time / 1000;
307        msecs = time - (secs * 1000);
308
309        /* calculate sample number fraction from msecs */
310        temp = (msecs * pState->sampleRate);
311        temp = (temp >> 10) + ((temp * 49) >> 21);
312
313        /* add integer sample count */
314        temp += secs * pState->sampleRate;
315
316#ifdef _DEBUG_IMA_ADPCM_LOCATE
317        EAS_ReportEx(_EAS_SEVERITY_NOFILTER, 0x2380b977, 0x00000006 , time, temp);
318#endif
319
320        /* for looped samples, calculate position in the loop */
321        if ((temp > pState->byteCount) && (pState->loopSamples != 0))
322        {
323            EAS_I32 numBlocks;
324            EAS_I32 samplesPerLoop;
325            EAS_I32 samplesInLastBlock;
326
327            numBlocks = (EAS_I32) (pState->loopStart / pState->blockSize);
328            samplesInLastBlock = (EAS_I32) pState->loopStart - (numBlocks * pState->blockSize);
329            if (samplesInLastBlock)
330            {
331                if (pState->flags & PCM_FLAGS_STEREO)
332                    samplesInLastBlock = samplesInLastBlock - 7;
333                else
334                    /*lint -e{703} use shift for performance */
335                    samplesInLastBlock = (samplesInLastBlock << 1) - 7;
336            }
337            samplesPerLoop = numBlocks * samplesPerBlock + samplesInLastBlock;
338            temp = temp % samplesPerLoop;
339#ifdef _DEBUG_IMA_ADPCM_LOCATE
340            EAS_ReportEx(_EAS_SEVERITY_NOFILTER, 0x2380b977, 0x00000007 , numBlocks, samplesPerLoop, samplesInLastBlock, temp);
341#endif
342        }
343
344        /* find start of block for requested sample */
345        temp = (temp / samplesPerBlock) * pState->blockSize;
346#ifdef _DEBUG_IMA_ADPCM_LOCATE
347        EAS_ReportEx(_EAS_SEVERITY_NOFILTER, 0x2380b977, 0x00000008 , temp);
348#endif
349
350    }
351
352    /* seek to new location */
353    if ((result = EAS_PESeek(pEASData, pState, &temp)) != EAS_SUCCESS)
354        return result;
355
356#ifdef _DEBUG_IMA_ADPCM_LOCATE
357    EAS_ReportEx(_EAS_SEVERITY_NOFILTER, 0x2380b977, 0x00000009 , pState->bytesLeft);
358#endif
359
360    /* reset state */
361    pState->blockCount = 0;
362    pState->hiNibble = EAS_FALSE;
363    if ((pState->state != EAS_STATE_PAUSING) && (pState->state != EAS_STATE_PAUSED))
364        pState->state = EAS_STATE_READY;
365
366    return EAS_SUCCESS;
367}
368
369