Created pommicket.github.io

1 files changed, 130 insertions, 0 deletions

diff --git a/js/riffwave.js b/js/riffwave.js
new file mode 100644
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+++ b/js/riffwave.js
@@ -0,0 +1,130 @@
+/* 
+ * RIFFWAVE.js v0.03 - Audio encoder for HTML5 <audio> elements.
+ * Copyleft 2011 by Pedro Ladaria <pedro.ladaria at Gmail dot com>
+ *
+ * Public Domain
+ *
+ * Changelog:
+ *
+ * 0.01 - First release
+ * 0.02 - New faster base64 encoding
+ * 0.03 - Support for 16bit samples
+ *
+ * Notes:
+ *
+ * 8 bit data is unsigned: 0..255
+ * 16 bit data is signed: −32,768..32,767
+ *
+ */
+
+var FastBase64 = {
+
+    chars: "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=",
+    encLookup: [],
+
+    Init: function() {
+        for (var i=0; i<4096; i++) {
+            this.encLookup[i] = this.chars[i >> 6] + this.chars[i & 0x3F];
+        }
+    },
+
+    Encode: function(src) {
+        var len = src.length;
+        var dst = '';
+        var i = 0;
+        while (len > 2) {
+            n = (src[i] << 16) | (src[i+1]<<8) | src[i+2];
+            dst+= this.encLookup[n >> 12] + this.encLookup[n & 0xFFF];
+            len-= 3;
+            i+= 3;
+        }
+        if (len > 0) {
+            var n1= (src[i] & 0xFC) >> 2;
+            var n2= (src[i] & 0x03) << 4;
+            if (len > 1) n2 |= (src[++i] & 0xF0) >> 4;
+            dst+= this.chars[n1];
+            dst+= this.chars[n2];
+            if (len == 2) {
+                var n3= (src[i++] & 0x0F) << 2;
+                n3 |= (src[i] & 0xC0) >> 6;
+                dst+= this.chars[n3];
+            }
+            if (len == 1) dst+= '=';
+            dst+= '=';
+        }
+        return dst;
+    } // end Encode
+
+}
+
+FastBase64.Init();
+
+var RIFFWAVE = function(data) {
+
+    this.data = [];        // Array containing audio samples
+    this.wav = [];         // Array containing the generated wave file
+    this.dataURI = '';     // http://en.wikipedia.org/wiki/Data_URI_scheme
+
+    this.header = {                         // OFFS SIZE NOTES
+        chunkId      : [0x52,0x49,0x46,0x46], // 0    4    "RIFF" = 0x52494646
+        chunkSize    : 0,                     // 4    4    36+SubChunk2Size = 4+(8+SubChunk1Size)+(8+SubChunk2Size)
+        format       : [0x57,0x41,0x56,0x45], // 8    4    "WAVE" = 0x57415645
+        subChunk1Id  : [0x66,0x6d,0x74,0x20], // 12   4    "fmt " = 0x666d7420
+        subChunk1Size: 16,                    // 16   4    16 for PCM
+        audioFormat  : 1,                     // 20   2    PCM = 1
+        numChannels  : 1,                     // 22   2    Mono = 1, Stereo = 2...
+        sampleRate   : 8000,                  // 24   4    8000, 44100...
+        byteRate     : 0,                     // 28   4    SampleRate*NumChannels*BitsPerSample/8
+        blockAlign   : 0,                     // 32   2    NumChannels*BitsPerSample/8
+        bitsPerSample: 8,                     // 34   2    8 bits = 8, 16 bits = 16
+        subChunk2Id  : [0x64,0x61,0x74,0x61], // 36   4    "data" = 0x64617461
+        subChunk2Size: 0                      // 40   4    data size = NumSamples*NumChannels*BitsPerSample/8
+    };
+
+    function u32ToArray(i) {
+        return [i&0xFF, (i>>8)&0xFF, (i>>16)&0xFF, (i>>24)&0xFF];
+    }
+
+    function u16ToArray(i) {
+        return [i&0xFF, (i>>8)&0xFF];
+    }
+
+    function split16bitArray(data) {
+        var r = [];
+        var j = 0;
+        var len = data.length;
+        for (var i=0; i<len; i++) {
+            r[j++] = data[i] & 0xFF;
+            r[j++] = (data[i]>>8) & 0xFF;
+        }
+        return r;
+    }
+
+    this.Make = function(data) {
+        if (data instanceof Array) this.data = data;
+        this.header.blockAlign = (this.header.numChannels * this.header.bitsPerSample) >> 3;
+        this.header.byteRate = this.header.blockAlign * this.sampleRate;
+        this.header.subChunk2Size = this.data.length * (this.header.bitsPerSample >> 3);
+        this.header.chunkSize = 36 + this.header.subChunk2Size;
+
+        this.wav = this.header.chunkId.concat(
+            u32ToArray(this.header.chunkSize),
+            this.header.format,
+            this.header.subChunk1Id,
+            u32ToArray(this.header.subChunk1Size),
+            u16ToArray(this.header.audioFormat),
+            u16ToArray(this.header.numChannels),
+            u32ToArray(this.header.sampleRate),
+            u32ToArray(this.header.byteRate),
+            u16ToArray(this.header.blockAlign),
+            u16ToArray(this.header.bitsPerSample),    
+            this.header.subChunk2Id,
+            u32ToArray(this.header.subChunk2Size),
+            (this.header.bitsPerSample == 16) ? split16bitArray(this.data) : this.data
+        );
+        this.dataURI = 'data:audio/wav;base64,'+FastBase64.Encode(this.wav);
+    };
+
+    if (data instanceof Array) this.Make(data);
+
+}; // end RIFFWAVE