First commit

Makefile

@@ -0,0 +1,10 @@
+CC = gcc
+CFLAGS = -Wall
+DEPS = wave.h
+OBJ = PCM_Wav_Play.o wave.o
+
+%.o %.c $(DEPS)
+        $(cc) $(CFLAGS) -c -o $@ $<
+
+PCM_Wav_Play : $(OBJ)
+        gcc $(CFLAGS) -o $@ $^

PCM_Wav_Play.c

@@ -0,0 +1,118 @@
+/*
+ * A simple code to read from a wav file 
+ * and play it. 
+ * 
+ * Adopted from the linux journal 
+ * https://www.linuxjournal.com/article/6735
+ * 
+ * */
+
+// Tell Alsa to use newer version of its API
+#define ALSA_PCM_NEW_HW_PARAMS_API
+
+#include <alsa/asoundlib.h>
+#include "wave_play.h"
+
+#define SECOND 1000000
+#define file_name "sample_wav.wav"
+/*
+ * 
+ * 
+ *
+ * */
+int main(){
+
+	// PCM device handle
+	snd_pcm_t *handle;
+	// Structure used to configure the PCM device
+	snd_pcm_hw_params_t *params;
+	// name of the device, default for now
+	char * device_name =  "default";
+	// Variable to store return values of functions
+	int return_val;
+	// frames used to determine size of a period
+	snd_pcm_uframes_t frames;
+	// Buffer to store data to be captured or played
+	char *buffer;
+	//char * file_name = "sample_wav.wav";
+	unsigned int size, sample_rate, period_time, loop_time, num_loops;
+
+	// open PCM device 
+	if ( (return_val = snd_pcm_open(&handle, device_name, 
+                    SND_PCM_STREAM_PLAYBACK, 0)) < 0){
+		fprintf(stderr, 
+            "unable to open pcm device %s : %s\n", device_name \
+            , snd_strerror(return_val));
+		exit(1);
+	}
+	fprintf(stdout, "PCM Device \"%s\" successfully opened\n" \
+			, device_name );
+
+    // Allocate params 
+	snd_pcm_hw_params_alloca(&params);
+	// Initialize with default values
+	snd_pcm_hw_params_any(handle, params);
+
+	// Set Configuration values in params
+	// set access type to RW interleaved and 
+	// check function callback 
+	if (snd_pcm_hw_params_set_access(handle, params,
+                      SND_PCM_ACCESS_RW_INTERLEAVED) < 0 ){
+		fprintf(stderr, 
+            "unable to set access type to RW Interleaved");
+		exit(1);					
+	}
+	// Set the data format to Signed 16-bit little-endian 
+	if (snd_pcm_hw_params_set_format(handle, params,
+                              SND_PCM_FORMAT_S16_LE) < 0 ){
+		fprintf(stderr, 
+            "unable to set format to Signed 16-bit little-endian");
+		exit(1);							 	
+	}
+	// set setrio channels
+	if (snd_pcm_hw_params_set_channels(handle, params, 2) < 0 ){
+		fprintf(stderr, 
+            "unable to set channel to sterio");
+		exit(1);
+	}
+	// sample rate of sample wav file is 256000 bits/second 
+	// Invalid argument error if Sample rate is higher than 200,000
+	sample_rate = 8000;
+	if (snd_pcm_hw_params_set_rate_near(handle, params, 
+                                  &sample_rate, 0) < 0){
+		fprintf(stderr, 
+            "unable to set sample rate to %d ",sample_rate);
+		exit(1);
+	}							  
+	// set period size to 32 frames. A frame has 2 samples, left and 
+	// right samples. A sample has 2 bytes, most and least significant. 
+	frames = 64;
+	fprintf(stdout,"Set number of frames is %d \n", frames);
+	if (snd_pcm_hw_params_set_period_size_near(handle,
+                              params, &frames, 0) < 0){
+		fprintf(stderr, 
+            "unable to set period size to %d frames",frames);
+		exit(1);						  	
+	}
+    // Finally, write the params to the actual hardware device
+	if ((return_val = snd_pcm_hw_params(handle, params)) < 0) {
+		fprintf(stderr, 
+            "unable to set hw parameters: %s\n",
+            snd_strerror(return_val));
+		exit(1);
+	}
+	// get actual period size. It could be different from 
+	// the previously set value. 
+	snd_pcm_hw_params_get_period_size(params, &frames,0);
+    fprintf(stdout,"Got a period size of %d \n", frames);
+
+	// This function will open a wav file and play it using
+	// the handle. 
+	read_wave_and_play(file_name, handle, frames);
+	// Drain and close the PCM handle
+	snd_pcm_drain(handle);
+	snd_pcm_close(handle);
+
+	return 0;
+
+}

README.md

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+# Alsa_Wave_Play

gcc_compile_script

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+gcc -I. PCM_Wav_Play.c wave_play.c -o PCM_Wav_Play -lasound

wave_play.c

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+/*
+ * 
+ * Wave.c
+ * A simple program to parse wav and play files .
+ * 
+ * Adopted from 
+ * http://truelogic.org/wordpress/2015/09/04/parsing-a-wav-file-in-c/
+ * 
+ * */
+
+// Tell Alsa to use newer version of its API
+
+#define ALSA_PCM_NEW_HW_PARAMS_API
+
+#include <alsa/asoundlib.h>
+
+#include <stdio.h>
+#include "wave_play.h"
+#include <unistd.h>
+#include <string.h>
+#include <stdlib.h>
+
+#define TRUE 1
+#define FALSE 0
+#define READ_in_CHUNKS 1
+#define HEADER_SIZE 44
+#define NUM_BYTES 4
+
+// struct for the
+struct WAV_HEADER wave_header; 
+// file ptr
+FILE *file_ptr; 
+unsigned char temp_buffer[4];
+unsigned char temp_buffer_2[2];
+
+int read_wave_and_play(char *file_name, snd_pcm_t *handle, 
+			snd_pcm_uframes_t frames){
+
+	int ret, data_size; 
+	long number_of_samples, size_of_samples, i = 0;
+	long low_limit=0l, high_limit = 0l;
+	float duration_in_sec;
+	char * data_temp_buffer;
+
+
+	fprintf(stdout,"Wave file reading started \n");
+
+	if ( (file_ptr = fopen(file_name, "rb") ) == NULL){
+			printf("error in opening file");
+			exit(1);
+	}
+
+	// read header data
+	ret = fread(wave_header.riff, sizeof(wave_header.riff),1,file_ptr);
+	printf("RIFF header values %s .\n",wave_header.riff);
+	// read file size
+	ret = fread(temp_buffer, sizeof(temp_buffer), 1, file_ptr);
+	wave_header.file_size = temp_buffer[0] | (temp_buffer[1] << 8) | \
+	                (temp_buffer[2] << 16) | (temp_buffer[3] << 24);
+	printf("Wav file size %u KB.\n",wave_header.file_size / 1024);
+	// get wav header
+	ret = fread(wave_header.wave, sizeof(wave_header.wave),1, file_ptr);
+	printf("Wave marker is %s .\n",wave_header.wave);
+	// fmt marker
+	ret = fread(wave_header.fmt_chunk_marker, \
+				sizeof(wave_header.fmt_chunk_marker), 1, file_ptr);
+	printf("Fmt chunk marker is %s .\n",wave_header.fmt_chunk_marker);
+	// read fmt length  
+	ret = fread(temp_buffer, sizeof(temp_buffer), 1, file_ptr);
+	wave_header.length_of_fmt = temp_buffer[0] | (temp_buffer[1] << 8) | \
+	                    (temp_buffer[2] << 16) | (temp_buffer[3] << 24);
+	printf("Length of fmt header %u B.\n", wave_header.length_of_fmt);
+	// get format type
+	ret = fread(temp_buffer_2, sizeof(temp_buffer_2), 1, file_ptr);
+	wave_header.format_type = temp_buffer_2[0] | temp_buffer_2[1] << 8 ;
+	switch(wave_header.format_type){
+		case (1): printf("Format type PCM \n");
+				 break;
+		default:  printf("Format type other \n");
+				 break;
+	}
+	// get channels
+	ret = fread(temp_buffer_2, sizeof(temp_buffer_2), 1, file_ptr);
+	wave_header.channels = temp_buffer_2[0] | temp_buffer_2[1] << 8 ;
+	printf("Channels %u .\n", wave_header.channels);
+	// read sample rate
+	ret = fread(temp_buffer, sizeof(temp_buffer), 1, file_ptr);
+	wave_header.sample_rate = temp_buffer[0] | (temp_buffer[1] << 8) | \
+	                (temp_buffer[2] << 16) | (temp_buffer[3] << 24);
+	printf("Sample rate %u .\n",wave_header.sample_rate);
+	// read byte rate
+	ret = fread(temp_buffer, sizeof(temp_buffer), 1, file_ptr);
+	wave_header.byterate = temp_buffer[0] | (temp_buffer[1] << 8) | \
+	                  (temp_buffer[2] << 16) | (temp_buffer[3] << 24);
+	printf("Byte rate %u.\n",wave_header.byterate);
+	// read block allignment 
+	ret = fread(temp_buffer_2, sizeof(temp_buffer_2), 1, file_ptr);
+	wave_header.block_align = temp_buffer_2[0] | temp_buffer_2[1] << 8 ;
+	printf("Block alignment %u .\n", wave_header.block_align);
+	// get bit's per sample
+	ret = fread(temp_buffer_2, sizeof(temp_buffer_2), 1, file_ptr);
+	wave_header.bits_per_sample = temp_buffer_2[0] | temp_buffer_2[1] << 8 ;
+	printf("Bit's per sample %u .\n", wave_header.bits_per_sample);
+	// read data marker
+	ret = fread(wave_header.data_chunk_header, 
+				sizeof(wave_header.data_chunk_header),
+				1, file_ptr);
+	printf("data_chunk_header %s .\n",wave_header.data_chunk_header);
+	// read data size
+	ret = fread(temp_buffer, sizeof(temp_buffer), 1, file_ptr);
+	wave_header.data_size = temp_buffer[0] | (temp_buffer[1] << 8) | \
+	                  (temp_buffer[2] << 16) | (temp_buffer[3] << 24);
+	printf("Data size %u .\n",wave_header.data_size );
+
+	// calculate number of samples; 
+	size_of_samples = (wave_header.channels * \
+						wave_header.bits_per_sample)/8;		
+	number_of_samples = ( 8 * wave_header.data_size) 
+				/ (size_of_samples);
+	duration_in_sec = (float) wave_header.file_size \
+				/ wave_header.byterate;
+    printf("%lu samples, each %ld bytes, %f seconds \n",
+			number_of_samples, size_of_samples, duration_in_sec);
+
+	// Reading all data at once 
+	// get actual data size
+	fseek(file_ptr, 0, SEEK_END);
+	data_size = ftell(file_ptr) - HEADER_SIZE;
+	printf("File size is %u %u %u\n", data_size, ftell(file_ptr) );
+	fseek(file_ptr, HEADER_SIZE, SEEK_SET);
+	// Read all data at once
+	if (!READ_in_CHUNKS){
+		data_temp_buffer = (char *) malloc(data_size );
+		ret = fread(data_temp_buffer, NUM_BYTES , data_size/NUM_BYTES, 
+					file_ptr);
+		printf("Num samp is %d, read is %d \n", data_size/NUM_BYTES, 
+					ret);
+		snd_pcm_writei(handle, data_temp_buffer, data_size/NUM_BYTES);
+		free(data_temp_buffer);
+
+	} 
+	else{
+		// reading chunks
+		// allocate temp_buffer for each chunk
+		data_temp_buffer = (char *) malloc(NUM_BYTES * frames);
+		// get the number of samples/chunks
+		number_of_samples = data_size/ (NUM_BYTES *frames);
+
+		for (i=0; i< number_of_samples; i++){
+
+			ret = fread(data_temp_buffer, NUM_BYTES ,frames, file_ptr);
+			printf("Reading sample %d of %d %lu samples \n",i,\
+				number_of_samples , sizeof(data_temp_buffer));
+			if (ret == 0) {
+				fprintf(stderr, "file reading error \n");
+				break;
+			} 
+			ret = snd_pcm_writei(handle, data_temp_buffer, frames);
+			if (ret == -EPIPE) {
+				///* EPIPE means underrun */
+				fprintf(stderr, "underrun occurred\n");
+				snd_pcm_prepare(handle);
+			} else if (ret < 0) {
+				fprintf(stderr,
+				  "error from writei: %s\n",
+				  snd_strerror(ret));
+			}  else if (ret != (int)frames) {
+				fprintf(stderr, 
+				  "short write, write %d frames\n", ret);
+			}
+		}
+	}
+	free(data_temp_buffer);
+	fclose(file_ptr);
+	return 0;
+}

wave_play.h

@@ -0,0 +1,33 @@
+
+/*
+ * 
+ * Wave.h 
+ * A header file for a simple wav file parser
+ * Adopted from 
+ * http://truelogic.org/wordpress/2015/09/04/parsing-a-wav-file-in-c/
+ * 
+ * */
+
+
+// A structure to hold header of a wave file
+struct WAV_HEADER{
+
+	unsigned char riff[4];             //Bytes for RIFF file format
+	unsigned int file_size;            // An int (4 bytes) for file size
+	unsigned char wave[4];             // Chars for file headers
+	unsigned char fmt_chunk_marker[4]; // fmt string data
+	unsigned int length_of_fmt;        // length of format data
+	unsigned int format_type;          // format type
+	unsigned int channels; 
+	unsigned int sample_rate;
+	unsigned int byterate;
+	unsigned int block_align;
+	unsigned int bits_per_sample; 
+	unsigned char data_chunk_header [4];
+	unsigned int data_size; 
+
+};
+
+
+int read_wave_and_play(char *file_name, snd_pcm_t *handle, 
+			snd_pcm_uframes_t frames);