Diff: wavplayer.cpp

Revision:

0:ae31fe6f181c

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/wavplayer.cpp	Thu Feb 23 14:35:52 2012 +0000
@@ -0,0 +1,153 @@
+/*
+ Library wave file player by Tom Coxon
+
+ Based on WAVEplayer by Vlad Cazan/Stephan Rochon modified by Tom Coxon to:
+
+ 1. Run correctly on the Embedded Artists LPCXpresso baseboard.
+ 2. To play 8 bit sample size in addition to original 16 bit
+ 3. To be more fault tolerant when playing wav files.
+*/
+
+#include "wavplayer.h"
+
+Ticker tick;
+
+AnalogOut DACout(p18);
+
+void WavPlayer::dac_out() {
+    if (DAC_on) {
+        DACout.write_u16(DAC_fifo[DAC_rptr]);
+        DAC_rptr=(DAC_rptr+1) & 0xff;
+    }
+}
+
+//void play_wave(char *wavname) {
+void WavPlayer::play_wave(char *wavname) {
+    unsigned chunk_id,chunk_size,channel;
+    unsigned data,samp_int,i;
+    short dac_data;
+    char *slice_buf;
+    short *data_sptr;
+    FMT_STRUCT wav_format;
+    FILE *wavfile;
+    long slice,num_slices;
+    DAC_wptr=0;
+    DAC_rptr=0;
+
+    size_t result;
+
+    for (i=0;i<256;i+=2) {
+        DAC_fifo[i]=0;
+        DAC_fifo[i+1]=3000;
+    }
+    DAC_wptr=4;
+    DAC_on=0;
+
+    printf("Playing wave file '%s'\r\n",wavname);
+
+    wavfile=fopen(wavname,"rb");
+    if (!wavfile) {
+        printf("Unable to open wav file '%s'\r\n",wavname);
+        exit(1);
+    }
+
+    fread(&chunk_id,4,1,wavfile);
+    fread(&chunk_size,4,1,wavfile);
+    while (!feof(wavfile)) {
+        printf("Read chunk ID 0x%x, size 0x%x\r\n",chunk_id,chunk_size);
+        switch (chunk_id) {
+            case 0x46464952:
+                fread(&data,4,1,wavfile);
+                printf("RIFF chunk\r\n");
+                printf("  chunk size %d (0x%x)\r\n",chunk_size,chunk_size);
+                printf("  RIFF type 0x%x\r\n",data);
+                break;
+            case 0x20746d66:
+                fread(&wav_format,sizeof(wav_format),1,wavfile);
+                printf("FORMAT chunk\r\n");
+                printf("  chunk size %d (0x%x)\r\n",chunk_size,chunk_size);
+                printf("  compression code %d\r\n",wav_format.comp_code);
+                printf("  %d channels\r\n",wav_format.num_channels);
+                printf("  %d samples/sec\r\n",wav_format.sample_rate);
+                printf("  %d bytes/sec\r\n",wav_format.avg_Bps);
+                printf("  block align %d\r\n",wav_format.block_align);
+                printf("  %d bits per sample\r\n",wav_format.sig_bps);
+                if (chunk_size > sizeof(wav_format))
+                    fseek(wavfile,chunk_size-sizeof(wav_format),SEEK_CUR);
+// create a slice buffer large enough to hold multiple slices
+                slice_buf=(char *)malloc(wav_format.block_align*SLICE_BUF_SIZE);
+                if (!slice_buf) {
+                    printf("Unable to malloc slice buffer");
+                    exit(1);
+                }
+                break;
+            case 0x61746164:
+                slice_buf=(char *)malloc(wav_format.block_align*SLICE_BUF_SIZE);
+                if (!slice_buf) {
+                    printf("Unable to malloc slice buffer");
+                    exit(1);
+                }
+                num_slices=chunk_size/wav_format.block_align;
+                printf("DATA chunk\r\n");
+                printf("  chunk size %d (0x%x)\r\n",chunk_size,chunk_size);
+                printf("  %d slices\r\n",num_slices);
+                printf("  Ideal sample interval=%d\r\n",(unsigned)(1000000.0/wav_format.sample_rate));
+                samp_int=1000000/(wav_format.sample_rate);
+                printf("  programmed interrupt tick interval=%d\r\n",samp_int);
+
+// starting up ticker to write samples out -- no printfs until tick.detach is called
+                tick.attach_us(this,&WavPlayer::dac_out, samp_int);
+                DAC_on=1;
+                for (slice=0;slice<num_slices;slice+=SLICE_BUF_SIZE) {
+
+                    result = fread(slice_buf,wav_format.block_align*SLICE_BUF_SIZE,1,wavfile);
+                    if (feof(wavfile)) {
+                        printf("Oops -- not enough slices in the wave file\r\n");
+
+                        break;
+                    }
+
+                    data_sptr=(short *)slice_buf;
+                    for (i=0;i<SLICE_BUF_SIZE;i++) {
+                        dac_data=0;
+
+// for a stereo wave file average the two channels.
+                        for (channel=0;channel<wav_format.num_channels;channel++) {
+                            switch (wav_format.sig_bps) {
+                                case 16:
+                                    dac_data+=(  ((int)(*data_sptr++)) +32768 );
+                                    break;
+                                case 8:
+                                    dac_data+=(  ((int)(*data_sptr++)) +32768 <<8);
+                                    break;
+                            }
+                        }
+                        DAC_fifo[DAC_wptr]=dac_data;
+                        DAC_wptr=(DAC_wptr+1) & 0xff;
+                        while (DAC_wptr==DAC_rptr) {
+                            wait_us(10);
+                        }
+                    }
+                }
+                DAC_on=0;
+                tick.detach();
+                printf("Ticker detached\r\n");
+                free(slice_buf);
+                break;
+            case 0x5453494c:
+                printf("INFO chunk, size %d\r\n",chunk_size);
+                fseek(wavfile,chunk_size,SEEK_CUR);
+                break;
+            default:
+                printf("unknown chunk type 0x%x, size %d\r\n",chunk_id,chunk_size);
+                data=fseek(wavfile,chunk_size,SEEK_CUR);
+                break;
+        }
+        fread(&chunk_id,4,1,wavfile);
+        fread(&chunk_size,4,1,wavfile);
+    }
+    printf("++++++++++++ Done with wave file ++++++++++\r\n");
+    fclose(wavfile);
+}
+
+