REVISION
Definition in file DECODER__wav.c.
#include "../SYSTEM/sys_hardware.h"
#include "../MESSAGE/message.h"
#include "../codec/codec.h"
#include "../coder/coder.h"
#include "decoder.h"
Include dependency graph for DECODER__wav.c:
Go to the source code of this file.
Functions | |
| BOOL | DECODER__wav (void) |
| Function serves as the wav decoder task handle. | |
| int | DECODER__wavdecode (BITSTRM_Obj *in, int *out) |
| Function serves as the WAV decoder to convert little-endian audio data into big-endian. | |
|
|
Function serves as the wav decoder task handle.
Definition at line 50 of file DECODER__wav.c. References Audio, st_DECODER::decodeBitstrm, Decoder, DECODER__wavdecode(), st_DECODER::firstPacketOffset, st_DECODER::flag, GEN_zeroOut(), st_AUDIO::offset, st_DECODER::pipe, PIPE_writeNext(), st_AUDIO::playtime, SAUDIOTIME_UPDT, and st_DECODER::status. Referenced by DECODER__wavfirst(). 00051 {
00052 unsigned long tmpUL;
00053 PIPE_Obj * pipe = &Decoder.pipe;
00054 int error = DECODE_NO_ERROR;
00055 int dataLength;
00056 BOOL ret = TRUE;
00057
00058 // Try to decode as long as output pipe is open.
00059 while( PIPE_writeFrameNum(pipe) )
00060 {
00061 BITSTRM_pack(Decoder.decodeBitstrm);
00062 dataLength = BITSTRM_numDataWords(Decoder.decodeBitstrm);
00063
00064 // YES. valid data detected, prepare to decode.
00065 if ( Decoder.flag & (DEC_FFWD|DEC_FRWD|DEC_MEDIASEEK) )
00066 {
00067 BITSTRM_remove(Decoder.decodeBitstrm, dataLength);
00068 if(Decoder.flag & DEC_MEDIASEEK)
00069 {
00070 wvEndOfReadPtr = Audio.offset;
00071 Decoder.flag &= ~DEC_MEDIASEEK;
00072 }
00073 else
00074 {
00075 if(Decoder.flag & DEC_FFWD) wvEndOfReadPtr += wvFastFwdLen;
00076 else if(wvEndOfReadPtr>wvFastFwdLen+Decoder.firstPacketOffset)
00077 wvEndOfReadPtr -= wvFastFwdLen;
00078 else
00079 {
00080 // Send silence to get rid of the noise.
00081 wvSilence = 6L*Decoder.status.bitRate/8000L;
00082 wvEndOfReadPtr = Decoder.firstPacketOffset;
00083 }
00084 }
00085 wvReadPtr = wvEndOfReadPtr;
00086 Decoder.flag &= ~(DEC_FFWD|DEC_FRWD);
00087 ret = FALSE;
00088 break;
00089 }
00090 else
00091 {
00092 if(wvSilence)
00093 {
00094 GEN_zeroOut((UINT16*)pipe->WrFrame.Frame, WAV_PIPE_FRAMELEN);
00095 wvSilence--;
00096 }
00097 else
00098 {
00099 // is there enough data to be decoded?
00100 if( dataLength < WAV_INPUT_BUFFER_SIZE - READ_THRESHOLD_WAV ) ret = FALSE;
00101
00102 if( dataLength < (Decoder.status.frameSize) )
00103 {
00104 // NO. data not enough yet, bring up media task.
00105 return ret;
00106 }
00107
00108 // decode the bitstream
00109 error = DECODER__wavdecode(Decoder.decodeBitstrm, (Int *)pipe->WrFrame.Frame);
00110 }
00111
00112 // no error, output the data, prepare for the next write as well.
00113 if (error == DECODE_NO_ERROR) PIPE_writeNext(pipe);
00114 }
00115 }
00116
00117 BITSTRM_pack(Decoder.decodeBitstrm);
00118 // Check to update time.
00119 tmpUL = 0;
00120 if(wvReadPtr > Decoder.firstPacketOffset)
00121 tmpUL = (wvReadPtr-Decoder.firstPacketOffset)/wvAverageWordRate;
00122 if ( Audio.playtime != tmpUL )
00123 {
00124 Audio.playtime = tmpUL;
00125 mMSG_send(sysMsgQ, SYS_MSG_ID, SAUDIOTIME_UPDT, DONTCARE, 0);
00126 }
00127
00128 return ret;
00129 }
|
Here is the call graph for this function:
|
||||||||||||
|
Function serves as the WAV decoder to convert little-endian audio data into big-endian.
Definition at line 143 of file DECODER__wav.c. References Decoder, st_WAVHEADER::nBitsPerSample, and st_DECODER::status. Referenced by DECODER__wav(). 00144 {
00145 int *pSrc, *pDst, *pDst1;
00146 int nBitsPerSample;
00147 int len;
00148
00149 pSrc = (int*)BITSTRM_readPtr(in);
00150 pDst = out;
00151 pDst1 = pDst + (WAV_PIPE_FRAMELEN/2);
00152
00153 //nBitsPerSample = Decoder.status.bitRate/(Decoder.status.numChannels*Decoder.status.sampleRate);
00154 nBitsPerSample = wvHeader.nBitsPerSample;
00155
00156 switch(Decoder.status.numChannels)
00157 {
00158 case 1: //Mono
00159 switch(nBitsPerSample)
00160 {
00161 case 8:
00162 len = WAV_PIPE_FRAMELEN/4;
00163 while(len--)
00164 {
00165 // *pDst = (((*pSrc) & 0x0FF00) - 128) >> 1;
00166 // Subtracting 8-bit unsigned data from 128 increases noise.
00167 *pDst1 =
00168 *pDst = (((*pSrc) & 0x0FF00)) >> 1;
00169
00170 // *pDst = ~(*pDst) + 1;
00171 // Converting to 2's complement increases noise.
00172 pDst++;
00173 pDst1++;
00174
00175 // *pDst = (((*pSrc) & 0x0FF) - 128) << 7;
00176 *pDst1 =
00177 *pDst = (((*pSrc) & 0x0FF) ) << 7;
00178 // *pDst = ~(*pDst) + 1;
00179 pDst++;
00180 pDst1++;
00181 pSrc++;
00182 }
00183 // Advances the read pointer.
00184 BITSTRM_remove(in, WAV_PIPE_FRAMELEN/4);
00185 wvReadPtr += WAV_PIPE_FRAMELEN/4;
00186 break;
00187
00188 case 16:
00189 len = WAV_PIPE_FRAMELEN/2;
00190 while(len--)
00191 {
00192 //*(pDst+(WAV_PIPE_FRAMELEN/2)) = (((*pSrc) & 0x0FF) << 8) | (((*pSrc) & 0x0FF00) >> 8);
00193 *pDst1 =
00194 *pDst = ((*pSrc) << 8) | (((*pSrc) >> 8) & 0x0FF);
00195
00196 pDst++;
00197 pDst1++;
00198 pSrc++;
00199 }
00200 // Advances the read pointer.
00201 BITSTRM_remove(in, WAV_PIPE_FRAMELEN/2);
00202 wvReadPtr += WAV_PIPE_FRAMELEN/2;
00203 break;
00204
00205 default:
00206 break;
00207 }
00208 break;
00209
00210 case 2: //Stereo
00211 switch(nBitsPerSample)
00212 {
00213 case 8:
00214 len = WAV_PIPE_FRAMELEN;
00215 while(len--)
00216 {
00217 if( len & 0x01 )
00218 {
00219 // Lower half Decoder.pipe.WrFrame.Frame stored left channel
00220 // samples (even address in Decoder.decodeBitstrm).
00221 //*pDst = (((*pSrc) & 0x0FF00) >> 8) << 7;
00222 *pDst = ((*pSrc) & 0x0FF00) >> 1 ;
00223 // *pDst = ~(*pDst) + 1;
00224 }
00225 else
00226 {
00227 // Upper half Decoder.pipe.WrFrame.Frame stored right channel
00228 // samples (odd address in Decoder.decodeBitstrm).
00229 *pDst1 = ((*pSrc) & 0x0FF) << 7;
00230 // *(pDst+(WAV_PIPE_FRAMELEN/2)) = ~(*(pDst+(WAV_PIPE_FRAMELEN/2))) + 1;
00231 pDst++;
00232 pDst1++;
00233 pSrc++;
00234 }
00235 }
00236 // Advances the read pointer.
00237 BITSTRM_remove(in, WAV_PIPE_FRAMELEN/2);
00238 wvReadPtr += WAV_PIPE_FRAMELEN/2;
00239 break;
00240
00241 case 16:
00242 // Stereo 16-bit Mode.
00243 // Read number of WAV_PIPE_FRAMELEN samples from decodeBitstrm.
00244 // Change data format from little-endian to big-endian.
00245 len = WAV_PIPE_FRAMELEN;
00246 while(len--)
00247 {
00248 if( len & 0x01 )
00249 {
00250 // Low-address half Decoder.pipe.WrFrame.Frame stored left channel
00251 // samples (even address in Decoder.decodeBitstrm).
00252 *pDst = ((*pSrc) << 8) | (((*pSrc) >> 8) & 0x0FF);
00253 pDst++;
00254 }
00255 else
00256 {
00257 // High-address half Decoder.pipe.WrFrame.Frame stored right channel
00258 // samples (odd address in Decoder.decodeBitstrm).
00259 *pDst1 = ((*pSrc) << 8) | (((*pSrc) >> 8) & 0x0FF);
00260 pDst1++;
00261 }
00262 pSrc++;
00263 }
00264
00265 // Advances the read pointer.
00266 BITSTRM_remove(in, WAV_PIPE_FRAMELEN);
00267 wvReadPtr += WAV_PIPE_FRAMELEN;
00268 break;
00269
00270 default:
00271 break;
00272 }
00273 break;
00274
00275 default:
00276 break;
00277 }
00278 return DECODE_NO_ERROR;
00279 }
|
1.3.9.1