mp3 test

assets/disk0/home/mp3test.js

@@ -0,0 +1,70 @@
+const Mp3 = require('mp3dec')
+const pcm = require("pcm")
+
+
+Object.keys(Mp3).forEach(e=>{
+    print(`${e}\t`)
+})
+println()
+
+println("reading...")
+let arr = files.open("A:/gateless.mp3").bread()
+let ab = new ArrayBuffer(arr.length)
+let abba = new Uint8Array(ab)
+arr.forEach((v,i)=>{ abba[i] = v })
+
+
+let mp3ArrayBuffer = new Uint8Array(ab, 0, arr.length)
+
+println("decoding...")
+let decoder = Mp3.newDecoder(ab)
+if (decoder === null) throw Error("decoder is null")
+
+audio.resetParams(0)
+audio.purgeQueue(0)
+audio.setPcmMode(0)
+audio.setMasterVolume(0, 255)
+audio.play(0)
+
+let decodedLength = 0
+let readPtr = sys.malloc(8000)
+let decodePtr = sys.malloc(12000)
+
+
+function decodeAndResample(readArr, decodePtr, readLength) {
+    for (let i = 0; i < readLength; i+= 2) {
+        let sample = pcm.u16Tos16(readArr[i] | (readArr[i+1] << 8))
+        let u8 = pcm.s16Tou8(sample)
+
+        sys.poke(decodePtr + (i >> 1), u8)
+    }
+    return readLength / 2
+}
+
+
+function printPlayBar() {
+}
+
+
+const QUEUE_MAX = 4
+decoder.decode(obj=>{
+    let buf = obj.buf
+    let err = obj.err
+
+    decodedLength += buf.byteLength
+
+    let declen = decodeAndResample(buf, decodePtr, buf.byteLength)
+
+    audio.putPcmDataByPtr(decodePtr, declen, 0)
+    audio.setSampleUploadLength(0, declen)
+    audio.startSampleUpload(0)
+    audio.play(0)
+
+    serial.println(`Send sample (${audio.getPosition(0)})`)
+//    sys.sleep(0) // decoding time is slower than realtime :(
+
+
+}) // now you got decoded PCM data
+
+sys.free(readPtr)
+sys.free(decodePtr)