shared-utils/test/create_sin_file.js

contains useful utilities to read/write WAV file to/from a buffer, various float to int conversions, 32 bit float to 16 bit int conversion, random number generator for ints or floats in which optionally uses same random sequence across runs

#!/usr/bin/env node 

var output_dir = process.argv[2] || "/tmp";

// var audio_utils = require("audio-utils").audio_utils();
var audio_utils = require("audio-utils");

console.log("audio_utils ", audio_utils);



var shared_utils = require("../");

console.log("shared_utils ", shared_utils);

// ---

var path = require('path');

function resolvePath(str) {
  if (str.substr(0, 2) === '~/') {
    str = (process.env.HOME || process.env.HOMEPATH || process.env.HOMEDIR || process.cwd()) + str.substr(1);
  }
  return path.resolve(str);
}

// -------------------------------------------------------- //

function cb_send_to_browser() {

	console.log("TOP TOP TOP cb_send_to_browser");

};

// ---

var cb_read_file_done = function(audio_obj) {

    console.log("cb_read_file_done ");
    console.log("cb_read_file_done ");
    console.log("cb_read_file_done ");
    console.log("cb_read_file_done ");

    shared_utils.show_object(audio_obj, 
        "backHome audio_obj 32 bit signed float   read_file_done", "total", 0);
};

// ------------------------------------------------------------------------------------ //

// shared_utils.set_random_seed(17); // comment out if U want fresh random sequence for each run ... o/w sequence repeats

// ------------  synthesize an audio buffer  ------------  //

/*
2^12 4096
2^13 8192
2^14 16384
2^15 32768
2^16 65536
2^17 131072
2^18 262144
2^19 524288
2^20 1048576
*/

// var SIZE_BUFFER_SOURCE = 5;
// var SIZE_BUFFER_SOURCE = 256;
// var SIZE_BUFFER_SOURCE = 4096;
// var SIZE_BUFFER_SOURCE = 16384;
// var SIZE_BUFFER_SOURCE = 32768;
// var SIZE_BUFFER_SOURCE = 65536;
// var SIZE_BUFFER_SOURCE = 262144;
var SIZE_BUFFER_SOURCE = 8388608;

var samples_per_cycle = 64;
// var samples_per_cycle = 128;  // lower tone
// var samples_per_cycle = 256;
// var samples_per_cycle = 512;  // higher tone
// var samples_per_cycle = 1024;  // higher tone

var source_obj = {}; // we populate its buffer with random float values then save to output WAV file 
var target_obj = {}; // then read back WAV file to populate this target buffer then do curve diff to confirm curves match

source_obj.buffer = new Float32Array(SIZE_BUFFER_SOURCE);

var max_index = SIZE_BUFFER_SOURCE;

source_obj = audio_utils.pop_audio_buffer(SIZE_BUFFER_SOURCE, samples_per_cycle);





/*
for (var index = 0; index < max_index; index++) {

    source_obj.buffer[index] = shared_utils.get_random_in_range_inclusive_float(-1.0, 1.0);

    console.log(index, " pop_audio_buffer ", source_obj.buffer[index]);
}
*/


// ----------------------------



// var output_dir = resolvePath(process.env.AUDIO_DIR);

var output_format = ".wav";

console.log(" output_dir ", output_dir);


// ---------- write to output file ------------- //


var source_wave = "source_sine_wave";

// var source_wave_filename = path.join(output_dir, source_wave + output_format);
var source_wave_filename = path.join(output_dir, source_wave + "_" + SIZE_BUFFER_SOURCE + "_" + samples_per_cycle + output_format);

// SIZE_BUFFER_SOURCE, samples_per_cycle 




console.log("source_wave_filename   ", source_wave_filename);

shared_utils.write_32_bit_float_buffer_to_16_bit_wav_file(source_obj, source_wave_filename);

console.log("source_wave_filename   ", source_wave_filename);

return;


// return;


// ------------ read wav file -------------------- //

console.log("\n\nread wav file\n\n");

// IF you have a pre-defined callback to handle output buffer use this
// shared_utils.read_wav_file(source_wave_filename, cb_read_file_done);

// __ELSE__ this just defines a callback when DONE inline

var MAX_DIFF_ERROR_PERMITTED = 0.1; // percentage error allowed when diffing audio curve pre -vs- post storing in WAV file

var cb_read_done = function(audio_obj) {

    console.log("cb_read_file_done ");

    console.log("populated buffer size ", audio_obj.buffer.length);

    shared_utils.show_object(audio_obj,
        "audio_obj 32 bit float   cb_read_done", "total", 10);

    var diff_spec = {};

    shared_utils.diff_buffers(source_obj, audio_obj, diff_spec);


    shared_utils.show_object(diff_spec,
        "diff_spec   cb_read_done", "total", 10);

    console.log("diff_spec.total_raw_left ", diff_spec.total_raw_left);
    console.log("diff_spec.total_raw_right ", diff_spec.total_raw_right);
    console.log("diff_spec.total_diffs ", diff_spec.total_diffs);
    console.log("diff_spec.size_buffer ", diff_spec.size_buffer);

    if (SIZE_BUFFER_SOURCE !== diff_spec.size_buffer) {

        console.error("ERROR - seeing mismatch diff_spec.size_buffer " + diff_spec.size_buffer,
            " is NOT same as SIZE_BUFFER_SOURCE " + SIZE_BUFFER_SOURCE);
    } else {

        console.log("OK - seeing exact match SIZE_BUFFER_SOURCE == diff_spec.size_buffer == ",
            diff_spec.size_buffer);
    }

    var actual_error_detected = (2.0 * SIZE_BUFFER_SOURCE * diff_spec.total_diffs) / 
                                (diff_spec.total_raw_left + diff_spec.total_raw_right);

    if (actual_error_detected < MAX_DIFF_ERROR_PERMITTED) {

        console.log("OK - actual_error_detected " + actual_error_detected + " < " +
            MAX_DIFF_ERROR_PERMITTED);

    } else {

        console.error("ERROR - actual_error_detected " + actual_error_detected +
                    " exceeds MAX_DIFF_ERROR_PERMITTED " + MAX_DIFF_ERROR_PERMITTED);
    }
};

shared_utils.read_wav_file(source_wave_filename, cb_read_done);


// ------------------ diff audio between source and target ------------- //
//
//      above we saved source audio buffer to output WAV file then read back WAV file to populate target buffer
//
//      below we diff buffers :  source -vs- target

console.log("source_obj.buffer.length ", source_obj.buffer.length);
// console.log("target_obj.buffer.length ", target_obj.buffer.length);

// --- done --- //