1 |
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2 | var JsMadProcessing = function(audio_id,active_workflow) {
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3 |
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4 | this.audio_id = audio_id;
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5 | this.active_workflow = active_workflow || null;
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6 |
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7 | var url = $('#'+audio_id).attr("href");
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8 | console.info("JsMadProcessing::JsMadProcessing() retrieving over AJAX: " + url);
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9 |
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10 | var stream = new Mad.AjaxStream(url);
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11 |
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12 | var that = this;
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13 |
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14 | var channels = 2; // stereo
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15 | var rate = 44100; // 44.1 Khz
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16 | //var rate = 48000; // 44.1 Khz
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17 | //var bufsize = 65536 * 4096;
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18 | //var bufsize = 65536 * 1024;
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19 | //var bufsize = 2048;
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20 | var bufsize = 1024 * 8;
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21 |
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22 | //this.dev = Sink(function(buffer) {that.refill(buffer)}, channels, bufsize, rate);
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23 | //console.log("*** got sample rate of: " + this.dev.sampleRate);
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24 |
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25 |
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26 | this.playBufferStore = new Array();
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27 |
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28 | /*
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29 | // default is to operate as fast as possible
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30 | if (BrowserDetect.browser == "Firefox") {
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31 | this.speedup_batch_limit = 100;
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32 | this.speedup_pause = 0;
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33 | }
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34 | else {
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35 | // e.g. Chrome
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36 | // => the following values played more nicely with letting DSP playback operate straightaway
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37 | // i.e. when jsmad is still working its way through the frames
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38 |
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39 | this.speedup_batch_limit = 10;
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40 | this.speedup_pause = 2;
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41 |
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42 | //speedup_batch_limit = 100;
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43 | //speedup_pause = 0;
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44 |
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45 | //console.log("*** Running JsMadProcessing with: batch limit = " + speedup_batch_limit
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46 | // + ", pause = " + this.speedup_pause + " msecs");
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47 | }
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48 | */
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49 |
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50 | // Assume slow, unless the user explicitly activates "speed up"
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51 | this.speedup_batch_limit = 10;
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52 | this.speedup_pause = 1000;
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53 |
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54 | this.processing_finished = false;
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55 |
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56 | stream.requestAbsolute(1 * 1024, function() { that.streamCallback(stream) });
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57 |
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58 | }
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59 |
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60 | JsMadProcessing.prototype.setSpeedupParams = function(new_batch_limit,new_pause) {
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61 | this.speedup_batch_limit = new_batch_limit;
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62 | this.speedup_pause = new_pause;
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63 | }
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64 |
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65 |
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66 | JsMadProcessing.prototype.processingFinished = function() {
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67 | return this.processing_finished;
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68 | }
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69 |
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70 | JsMadProcessing.prototype.streamCallback = function(stream) {
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71 |
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72 |
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73 | var mp3 = new Mad.MP3File(stream);
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74 | var mpeg = mp3.getMpegStream();
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75 |
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76 | //var howmuch = 10000;
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77 | var ss1 = Date.now();
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78 |
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79 | var synth = new Mad.Synth();
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80 | var frame = new Mad.Frame();
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81 |
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82 | frame = Mad.Frame.decode(frame, mpeg); // decode first frame to establish num channels and samplerate
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83 | var num_channels = frame.header.nchannels();
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84 | var sampleRate = frame.header.samplerate;
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85 |
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86 | console.info("JsMadProcessing::streamCallback() decoding URL retrieved MP3 with " + num_channels + " channels, samplerate = " + sampleRate);
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87 |
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88 |
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89 | var that = this;
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90 |
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91 | var numSamples = 0;
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92 |
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93 | synth.frame(frame);
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94 | var prev_synth_frame_len = synth.pcm.samples[0].length;
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95 | console.info("JsMadProcesing.streamCallback(): synth frame length (initial frame) = " + prev_synth_frame_len);
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96 |
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97 | var i=1; // already processed one frame
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98 |
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99 | var overflowBuffer = null;
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100 |
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101 | console.log("*** main-jsmad.js::stream_callback(): hardwiring workflow buffer size to 2048");
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102 |
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103 | var $acc_proc_status = $('#accProcStatus') || null;
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104 |
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105 |
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106 | (function() {
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107 |
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108 | var more_frames = 1;
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109 | try {
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110 |
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111 | var speedup_i = 0;
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112 |
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113 | while (speedup_i < that.speedup_batch_limit) { // Decode 100 frames at a time, before setTimeout break
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114 |
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115 | frame = Mad.Frame.decode(frame, mpeg);
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116 | synth.frame(frame);
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117 |
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118 | var synth_frame_len = synth.pcm.samples[0].length;
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119 |
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120 | var playBuffer = null;
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121 | var pbp = 0; // pbp = play buffer pos
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122 |
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123 | if (overflowBuffer != null) {
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124 | playBuffer = new Float32Array(overflowBuffer.length+(synth_frame_len*num_channels));
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125 | playBuffer.set(overflowBuffer);
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126 | pbp = overflowBuffer.length;
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127 | overflowBuffer = null;
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128 | }
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129 | else {
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130 | playBuffer = new Float32Array(synth_frame_len*num_channels);
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131 | pbp = 0;
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132 | }
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133 |
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134 |
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135 | for (var sfp=0; sfp<synth_frame_len; sfp++) {
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136 | for (var c=0; c<num_channels; c++) {
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137 | playBuffer[pbp] = synth.pcm.samples[c][sfp];
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138 | pbp++;
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139 | }
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140 | }
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141 |
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142 | numSamples += synth_frame_len;
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143 |
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144 | // uncomment the following line if you want to hear speeded-up playback as it works through the audio file
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145 | //var written = pannedPlayback.mozWriteAudio(playBuffer);
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146 |
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147 |
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148 | if (synth_frame_len != prev_synth_frame_len) {
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149 | console.log("*** new synth frame len (frame num = " + i + "): len = " + synth_frame_len);
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150 | prev_synth_frame_len = synth_frame_len;
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151 | }
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152 |
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153 | if (that.active_workflow != null) {
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154 | // Send the data into the Javascript DSP workflow
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155 |
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156 | // Note: workflow geared to 2048 samples at a time
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157 |
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158 | var wi = 0;
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159 |
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160 | var playBufferLen = playBuffer.length;
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161 | while (wi<playBuffer.length) {
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162 |
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163 | if (wi+2048<=playBufferLen) {
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164 | var workflowBuffer = playBuffer.subarray(wi,wi+2048);
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165 | that.active_workflow.pumpDataHead("rawInput",workflowBuffer);
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166 | that.playBufferStore.push(workflowBuffer);
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167 | }
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168 | else {
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169 | // tail end => set up in overflow buffer
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170 | var workflowBufferTail = playBuffer.subarray(wi);
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171 |
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172 | overflowBuffer = new Float32Array(playBufferLen-wi);
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173 | overflowBuffer.set(workflowBufferTail);
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174 |
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175 | }
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176 | wi += 2048;
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177 | }
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178 |
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179 |
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180 | // Old approach: pump data in, in frames that are set by webAudioContext
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181 | //that.active_workflow.pumpDataHead("rawInput",playBuffer);
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182 | }
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183 |
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184 | speedup_i++;
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185 | i++;
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186 |
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187 |
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188 | if ((i%10)==0) {
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189 | if ($acc_proc_status != null) {
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190 | $acc_proc_status.text(" (decoded " + i + " frames)");
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191 | }
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192 | }
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193 |
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194 | }
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195 |
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196 | }
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197 | catch(err) {
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198 | if (err == "Header decoding failed") {
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199 | console.info("JsMadProcessing::streamCallack() decoded " + i + " frames");
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200 | $acc_proc_status.text(" (done)");
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201 | that.processing_finished = true;
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202 | }
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203 | else {
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204 | console.error(err);
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205 | }
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206 | more_frames = 0;
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207 | }
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208 |
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209 | if (more_frames) {
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210 | setTimeout(arguments.callee,that.speedup_pause); // even a delay of '0' gives the browser thread a break
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211 | }
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212 | else {
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213 | var ss2 = Date.now();
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214 |
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215 | var song_duration = numSamples / sampleRate;
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216 | var speedup_duration = (ss2 - ss1)/1000;
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217 |
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218 | var speedup_factor = song_duration / speedup_duration;
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219 | //console.log("Computed song duration: " + song_duration + " secs");
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220 | console.info("JsMad processing done in " + speedup_duration + " secs (a speed factor of " + speedup_factor + ")");
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221 |
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222 | $acc_proc_status.text(" (done)");
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223 | that.processing_finished = true;
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224 |
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225 | }
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226 |
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227 | })();
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228 |
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229 | }
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230 |
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231 |
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232 | JsMadProcessing.prototype.refill = function(buffer)
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233 | {
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234 | console.log("refill called, asking for size = " + buffer.length);
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235 |
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236 | var buffer_len = buffer.length;
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237 | var buffer_pos = 0;
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238 |
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239 | while ((this.playBufferStore.length>0) && (buffer_pos<buffer_len)) {
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240 |
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241 | var playBuffer = this.playBufferStore.shift();
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242 | buffer.set(playBuffer,buffer_pos);
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243 |
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244 | buffer_pos += playBuffer.length;
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245 | }
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246 |
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247 |
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248 | }
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