nivedita velagaleti / wave_player_appbd

amended wave player

Fork of wave_player_appbd by jim hamblen

wave_player.cpp@3:b10ea1b38f08, 2015-04-09 (annotated)

Committer:
niv17
Date:
Thu Apr 09 20:23:37 2015 +0000
Revision:
3:b10ea1b38f08
Parent:
2:b1cea7afcfd2 
check code. find how to fix the buffer.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
sravet 0:62c18ade9a60 1 //-----------------------------------------------------------------------------
sravet 0:62c18ade9a60 2 // a sample mbed library to play back wave files.
sravet 0:62c18ade9a60 3 //
sravet 0:62c18ade9a60 4 // explanation of wave file format.
sravet 0:62c18ade9a60 5 // https://ccrma.stanford.edu/courses/422/projects/WaveFormat/
sravet 0:62c18ade9a60 6
sravet 0:62c18ade9a60 7 // if VERBOSE is uncommented then the wave player will enter a verbose
sravet 0:62c18ade9a60 8 // mode that displays all data values as it reads them from the file
sravet 0:62c18ade9a60 9 // and writes them to the DAC. Very slow and unusable output on the DAC,
sravet 0:62c18ade9a60 10 // but useful for debugging wave files that don't work.
sravet 0:62c18ade9a60 11 //#define VERBOSE
sravet 0:62c18ade9a60 12
sravet 0:62c18ade9a60 13
sravet 0:62c18ade9a60 14 #include <mbed.h>
sravet 0:62c18ade9a60 15 #include <stdio.h>
sravet 0:62c18ade9a60 16 #include <wave_player.h>
niv17 3:b10ea1b38f08 17 //Serial terminal(USBTX,USBRX);
sravet 0:62c18ade9a60 18
sravet 0:62c18ade9a60 19 //-----------------------------------------------------------------------------
sravet 0:62c18ade9a60 20 // constructor -- accepts an mbed pin to use for AnalogOut. Only p18 will work
niv17 3:b10ea1b38f08 21 wave_player::wave_player(AnalogOut *_dac, PwmOut *_pwm, unsigned short * waveArray)
4180_1 2:b1cea7afcfd2 22 {
4180_1 2:b1cea7afcfd2 23
4180_1 2:b1cea7afcfd2 24
4180_1 2:b1cea7afcfd2 25 wave_PWM= _pwm;
sravet 0:62c18ade9a60 26 wave_DAC=_dac;
sravet 0:62c18ade9a60 27 wave_DAC->write_u16(32768); //DAC is 0-3.3V, so idles at ~1.6V
4180_1 2:b1cea7afcfd2 28 *wave_PWM=32768;
sravet 0:62c18ade9a60 29 verbosity=0;
niv17 3:b10ea1b38f08 30 wavebuf = waveArray;
sravet 0:62c18ade9a60 31 }
sravet 0:62c18ade9a60 32
sravet 0:62c18ade9a60 33 //-----------------------------------------------------------------------------
sravet 0:62c18ade9a60 34 // if verbosity is set then wave player enters a mode where the wave file
sravet 0:62c18ade9a60 35 // is decoded and displayed to the screen, including sample values put into
sravet 0:62c18ade9a60 36 // the DAC FIFO, and values read out of the DAC FIFO by the ISR. The DAC output
sravet 0:62c18ade9a60 37 // itself is so slow as to be unusable, but this might be handy for debugging
sravet 0:62c18ade9a60 38 // wave files that don't play
sravet 0:62c18ade9a60 39 //-----------------------------------------------------------------------------
sravet 0:62c18ade9a60 40 void wave_player::set_verbosity(int v)
sravet 0:62c18ade9a60 41 {
sravet 0:62c18ade9a60 42 verbosity=v;
sravet 0:62c18ade9a60 43 }
sravet 0:62c18ade9a60 44
niv17 3:b10ea1b38f08 45
niv17 3:b10ea1b38f08 46
sravet 0:62c18ade9a60 47 //-----------------------------------------------------------------------------
sravet 0:62c18ade9a60 48 // player function. Takes a pointer to an opened wave file. The file needs
sravet 0:62c18ade9a60 49 // to be stored in a filesystem with enough bandwidth to feed the wave data.
sravet 0:62c18ade9a60 50 // LocalFileSystem isn't, but the SDcard is, at least for 22kHz files. The
sravet 0:62c18ade9a60 51 // SDcard filesystem can be hotrodded by increasing the SPI frequency it uses
sravet 0:62c18ade9a60 52 // internally.
sravet 0:62c18ade9a60 53 //-----------------------------------------------------------------------------
niv17 3:b10ea1b38f08 54
niv17 3:b10ea1b38f08 55
niv17 3:b10ea1b38f08 56
sravet 0:62c18ade9a60 57 void wave_player::play(FILE *wavefile)
sravet 0:62c18ade9a60 58 {
sravet 0:62c18ade9a60 59 unsigned chunk_id,chunk_size,channel;
sravet 0:62c18ade9a60 60 unsigned data,samp_int,i;
sravet 0:62c18ade9a60 61 short unsigned dac_data;
sravet 0:62c18ade9a60 62 long long slice_value;
sravet 0:62c18ade9a60 63 char *slice_buf;
sravet 0:62c18ade9a60 64 short *data_sptr;
sravet 0:62c18ade9a60 65 unsigned char *data_bptr;
sravet 0:62c18ade9a60 66 int *data_wptr;
sravet 0:62c18ade9a60 67 FMT_STRUCT wav_format;
sravet 0:62c18ade9a60 68 long slice,num_slices;
sravet 0:62c18ade9a60 69 DAC_wptr=0;
sravet 0:62c18ade9a60 70 DAC_rptr=0;
sravet 0:62c18ade9a60 71 for (i=0;i<256;i+=2) {
sravet 0:62c18ade9a60 72 DAC_fifo[i]=0;
sravet 0:62c18ade9a60 73 DAC_fifo[i+1]=3000;
sravet 0:62c18ade9a60 74 }
sravet 0:62c18ade9a60 75 DAC_wptr=4;
sravet 0:62c18ade9a60 76 DAC_on=0;
sravet 0:62c18ade9a60 77
sravet 0:62c18ade9a60 78 fread(&chunk_id,4,1,wavefile);
sravet 0:62c18ade9a60 79 fread(&chunk_size,4,1,wavefile);
sravet 0:62c18ade9a60 80 while (!feof(wavefile)) {
sravet 0:62c18ade9a60 81 if (verbosity)
sravet 0:62c18ade9a60 82 printf("Read chunk ID 0x%x, size 0x%x\n",chunk_id,chunk_size);
sravet 0:62c18ade9a60 83 switch (chunk_id) {
sravet 0:62c18ade9a60 84 case 0x46464952:
sravet 0:62c18ade9a60 85 fread(&data,4,1,wavefile);
sravet 0:62c18ade9a60 86 if (verbosity) {
sravet 0:62c18ade9a60 87 printf("RIFF chunk\n");
sravet 0:62c18ade9a60 88 printf(" chunk size %d (0x%x)\n",chunk_size,chunk_size);
sravet 0:62c18ade9a60 89 printf(" RIFF type 0x%x\n",data);
sravet 0:62c18ade9a60 90 }
sravet 0:62c18ade9a60 91 break;
sravet 0:62c18ade9a60 92 case 0x20746d66:
sravet 0:62c18ade9a60 93 fread(&wav_format,sizeof(wav_format),1,wavefile);
sravet 0:62c18ade9a60 94 if (verbosity) {
sravet 0:62c18ade9a60 95 printf("FORMAT chunk\n");
sravet 0:62c18ade9a60 96 printf(" chunk size %d (0x%x)\n",chunk_size,chunk_size);
sravet 0:62c18ade9a60 97 printf(" compression code %d\n",wav_format.comp_code);
sravet 0:62c18ade9a60 98 printf(" %d channels\n",wav_format.num_channels);
sravet 0:62c18ade9a60 99 printf(" %d samples/sec\n",wav_format.sample_rate);
sravet 0:62c18ade9a60 100 printf(" %d bytes/sec\n",wav_format.avg_Bps);
sravet 0:62c18ade9a60 101 printf(" block align %d\n",wav_format.block_align);
sravet 0:62c18ade9a60 102 printf(" %d bits per sample\n",wav_format.sig_bps);
sravet 0:62c18ade9a60 103 }
sravet 0:62c18ade9a60 104 if (chunk_size > sizeof(wav_format))
sravet 0:62c18ade9a60 105 fseek(wavefile,chunk_size-sizeof(wav_format),SEEK_CUR);
sravet 0:62c18ade9a60 106 break;
sravet 0:62c18ade9a60 107 case 0x61746164:
sravet 0:62c18ade9a60 108 // allocate a buffer big enough to hold a slice
sravet 0:62c18ade9a60 109 slice_buf=(char *)malloc(wav_format.block_align);
sravet 0:62c18ade9a60 110 if (!slice_buf) {
sravet 0:62c18ade9a60 111 printf("Unable to malloc slice buffer");
sravet 0:62c18ade9a60 112 exit(1);
sravet 0:62c18ade9a60 113 }
sravet 0:62c18ade9a60 114 num_slices=chunk_size/wav_format.block_align;
sravet 0:62c18ade9a60 115 samp_int=1000000/(wav_format.sample_rate);
sravet 0:62c18ade9a60 116 if (verbosity) {
sravet 0:62c18ade9a60 117 printf("DATA chunk\n");
sravet 0:62c18ade9a60 118 printf(" chunk size %d (0x%x)\n",chunk_size,chunk_size);
sravet 0:62c18ade9a60 119 printf(" %d slices\n",num_slices);
sravet 0:62c18ade9a60 120 printf(" Ideal sample interval=%d\n",(unsigned)(1000000.0/wav_format.sample_rate));
sravet 0:62c18ade9a60 121 printf(" programmed interrupt tick interval=%d\n",samp_int);
sravet 0:62c18ade9a60 122 }
sravet 0:62c18ade9a60 123
sravet 0:62c18ade9a60 124 // starting up ticker to write samples out -- no printfs until tick.detach is called
sravet 0:62c18ade9a60 125 if (verbosity)
sravet 0:62c18ade9a60 126 tick.attach_us(this,&wave_player::dac_out, 500000);
niv17 3:b10ea1b38f08 127 else{
niv17 3:b10ea1b38f08 128 //wavebuf[DAC_rptr] = DAC_fifo[DAC_rptr];
sravet 0:62c18ade9a60 129 tick.attach_us(this,&wave_player::dac_out, samp_int);
niv17 3:b10ea1b38f08 130 }
sravet 0:62c18ade9a60 131 DAC_on=1;
sravet 0:62c18ade9a60 132
sravet 0:62c18ade9a60 133 // start reading slices, which contain one sample each for however many channels
sravet 0:62c18ade9a60 134 // are in the wave file. one channel=mono, two channels=stereo, etc. Since
sravet 0:62c18ade9a60 135 // mbed only has a single AnalogOut, all of the channels present are averaged
sravet 0:62c18ade9a60 136 // to produce a single sample value. This summing and averaging happens in
sravet 0:62c18ade9a60 137 // a variable of type signed long long, to make sure that the data doesn't
sravet 0:62c18ade9a60 138 // overflow regardless of sample size (8 bits, 16 bits, 32 bits).
sravet 0:62c18ade9a60 139 //
sravet 0:62c18ade9a60 140 // note that from what I can find that 8 bit wave files use unsigned data,
sravet 0:62c18ade9a60 141 // while 16 and 32 bit wave files use signed data
sravet 0:62c18ade9a60 142 //
sravet 0:62c18ade9a60 143 for (slice=0;slice<num_slices;slice+=1) {
sravet 0:62c18ade9a60 144 fread(slice_buf,wav_format.block_align,1,wavefile);
sravet 0:62c18ade9a60 145 if (feof(wavefile)) {
sravet 0:62c18ade9a60 146 printf("Oops -- not enough slices in the wave file\n");
sravet 0:62c18ade9a60 147 exit(1);
sravet 0:62c18ade9a60 148 }
sravet 0:62c18ade9a60 149 data_sptr=(short *)slice_buf; // 16 bit samples
sravet 0:62c18ade9a60 150 data_bptr=(unsigned char *)slice_buf; // 8 bit samples
sravet 0:62c18ade9a60 151 data_wptr=(int *)slice_buf; // 32 bit samples
sravet 0:62c18ade9a60 152 slice_value=0;
sravet 0:62c18ade9a60 153 for (channel=0;channel<wav_format.num_channels;channel++) {
sravet 0:62c18ade9a60 154 switch (wav_format.sig_bps) {
sravet 0:62c18ade9a60 155 case 16:
sravet 0:62c18ade9a60 156 if (verbosity)
sravet 0:62c18ade9a60 157 printf("16 bit channel %d data=%d ",channel,data_sptr[channel]);
sravet 0:62c18ade9a60 158 slice_value+=data_sptr[channel];
sravet 0:62c18ade9a60 159 break;
sravet 0:62c18ade9a60 160 case 32:
sravet 0:62c18ade9a60 161 if (verbosity)
sravet 0:62c18ade9a60 162 printf("32 bit channel %d data=%d ",channel,data_wptr[channel]);
sravet 0:62c18ade9a60 163 slice_value+=data_wptr[channel];
sravet 0:62c18ade9a60 164 break;
sravet 0:62c18ade9a60 165 case 8:
sravet 0:62c18ade9a60 166 if (verbosity)
sravet 0:62c18ade9a60 167 printf("8 bit channel %d data=%d ",channel,(int)data_bptr[channel]);
sravet 0:62c18ade9a60 168 slice_value+=data_bptr[channel];
sravet 0:62c18ade9a60 169 break;
sravet 0:62c18ade9a60 170 }
sravet 0:62c18ade9a60 171 }
sravet 0:62c18ade9a60 172 slice_value/=wav_format.num_channels;
sravet 0:62c18ade9a60 173
sravet 0:62c18ade9a60 174 // slice_value is now averaged. Next it needs to be scaled to an unsigned 16 bit value
sravet 0:62c18ade9a60 175 // with DC offset so it can be written to the DAC.
sravet 0:62c18ade9a60 176 switch (wav_format.sig_bps) {
sravet 0:62c18ade9a60 177 case 8: slice_value<<=8;
sravet 0:62c18ade9a60 178 break;
sravet 0:62c18ade9a60 179 case 16: slice_value+=32768;
sravet 0:62c18ade9a60 180 break;
sravet 0:62c18ade9a60 181 case 32: slice_value>>=16;
sravet 0:62c18ade9a60 182 slice_value+=32768;
sravet 0:62c18ade9a60 183 break;
sravet 0:62c18ade9a60 184 }
sravet 0:62c18ade9a60 185 dac_data=(short unsigned)slice_value;
sravet 0:62c18ade9a60 186 if (verbosity)
sravet 0:62c18ade9a60 187 printf("sample %d wptr %d slice_value %d dac_data %u\n",slice,DAC_wptr,(int)slice_value,dac_data);
sravet 0:62c18ade9a60 188 DAC_fifo[DAC_wptr]=dac_data;
sravet 0:62c18ade9a60 189 DAC_wptr=(DAC_wptr+1) & 0xff;
sravet 0:62c18ade9a60 190 while (DAC_wptr==DAC_rptr) {
sravet 0:62c18ade9a60 191 }
sravet 0:62c18ade9a60 192 }
sravet 0:62c18ade9a60 193 DAC_on=0;
sravet 0:62c18ade9a60 194 tick.detach();
sravet 0:62c18ade9a60 195 free(slice_buf);
sravet 0:62c18ade9a60 196 break;
sravet 0:62c18ade9a60 197 case 0x5453494c:
sravet 0:62c18ade9a60 198 if (verbosity)
sravet 0:62c18ade9a60 199 printf("INFO chunk, size %d\n",chunk_size);
sravet 0:62c18ade9a60 200 fseek(wavefile,chunk_size,SEEK_CUR);
sravet 0:62c18ade9a60 201 break;
sravet 0:62c18ade9a60 202 default:
sravet 0:62c18ade9a60 203 printf("unknown chunk type 0x%x, size %d\n",chunk_id,chunk_size);
sravet 0:62c18ade9a60 204 data=fseek(wavefile,chunk_size,SEEK_CUR);
sravet 0:62c18ade9a60 205 break;
sravet 0:62c18ade9a60 206 }
sravet 0:62c18ade9a60 207 fread(&chunk_id,4,1,wavefile);
sravet 0:62c18ade9a60 208 fread(&chunk_size,4,1,wavefile);
sravet 0:62c18ade9a60 209 }
niv17 3:b10ea1b38f08 210 printf("\r\n********************END OF FILE*************\n");
sravet 0:62c18ade9a60 211 }
sravet 0:62c18ade9a60 212
sravet 0:62c18ade9a60 213
sravet 0:62c18ade9a60 214 void wave_player::dac_out()
sravet 0:62c18ade9a60 215 {
niv17 3:b10ea1b38f08 216
sravet 0:62c18ade9a60 217 if (DAC_on) {
sravet 0:62c18ade9a60 218 #ifdef VERBOSE
sravet 0:62c18ade9a60 219 printf("ISR rdptr %d got %u\n",DAC_rptr,DAC_fifo[DAC_rptr]);
sravet 0:62c18ade9a60 220 #endif
4180_1 2:b1cea7afcfd2 221 //scale down Analog voltage by 8 for PC speakers
niv17 3:b10ea1b38f08 222 wave_DAC->write_u16(DAC_fifo[DAC_rptr]>>3); // --removed
4180_1 2:b1cea7afcfd2 223 //Output to onboard speaker using PWM (Class D Audio Amp!)
niv17 3:b10ea1b38f08 224 wave_PWM->write(float(DAC_fifo[DAC_rptr]/65536.0)); // --removed
niv17 3:b10ea1b38f08 225
niv17 3:b10ea1b38f08 226
sravet 0:62c18ade9a60 227 DAC_rptr=(DAC_rptr+1) & 0xff;
sravet 0:62c18ade9a60 228 }
niv17 3:b10ea1b38f08 229
niv17 3:b10ea1b38f08 230
niv17 3:b10ea1b38f08 231
niv17 3:b10ea1b38f08 232
sravet 0:62c18ade9a60 233 }
sravet 0:62c18ade9a60 234
niv17 3:b10ea1b38f08 235 void wave_player::getFIFO(unsigned short * buf){
niv17 3:b10ea1b38f08 236 printf("\n*******PRINT FIFO********\r\n");
niv17 3:b10ea1b38f08 237 // buf = DAC_fifo;
niv17 3:b10ea1b38f08 238 for(int i =0; i<256; i++)
niv17 3:b10ea1b38f08 239 buf[i] = DAC_fifo[i];
niv17 3:b10ea1b38f08 240 printf("\n*******END OF FIFO********\r\n");
niv17 3:b10ea1b38f08 241 }