playwav now resamples LPCM

This commit is contained in:
minjaesong
2023-01-05 18:22:03 +09:00
parent 049064cca5
commit 006ff5015b
4 changed files with 203 additions and 34 deletions

View File

@@ -1,10 +1,10 @@
// this program will serve as a step towards the ADPCM decoding, and tests if RIFF data are successfully decoded.
let HW_SAMPLING_RATE = 30000
let filename = exec_args[1]
const port = _TVDOS.DRV.FS.SERIAL._toPorts("A")[0]
function printdbg(s) {
if (0) serial.println(s)
if (1) serial.println(s)
}
@@ -92,14 +92,14 @@ function readBytes(length, ptrToDecode) {
function readInt() {
let b = readBytes(4)
let i = (sys.peek(b) & 255) | ((sys.peek(b+1) & 255) << 8) | ((sys.peek(b+2) & 255) << 16) | ((sys.peek(b+3) & 255) << 24)
let i = (sys.peek(b)) | (sys.peek(b+1) << 8) | (sys.peek(b+2) << 16) | (sys.peek(b+3) << 24)
sys.free(b)
return i
}
function readShort() {
let b = readBytes(2)
let i = (sys.peek(b) & 255) | ((sys.peek(b+1) & 255) << 8)
let i = (sys.peek(b)) | (sys.peek(b+1) << 8)
sys.free(b)
return i
}
@@ -134,6 +134,29 @@ function printComments() {
}
}
function GCD(a, b) {
a = Math.abs(a)
b = Math.abs(b)
if (b > a) {var temp = a; a = b; b = temp}
while (true) {
if (b == 0) return a
a %= b
if (a == 0) return b
b %= a
}
}
function LCM(a, b) {
return (!a || !b) ? 0 : Math.abs((a * b) / GCD(a, b))
}
function lerp(start, end, x) {
return (1 - x) * start + x * end
}
function lerpAndRound(start, end, x) {
return Math.round(lerp(start, end, x))
}
// decode header
if (readFourCC() != "RIFF") {
@@ -160,33 +183,166 @@ let comments = {};
let readPtr = undefined
let decodePtr = undefined
function clampS16(i) { return (i < -32768) ? -32768 : (i > 32767) ? 32767 : i }
const uNybToSnyb = [0,1,2,3,4,5,6,7,-8,-7,-6,-5,-4,-3,-2,-1]
// returns: [unsigned high, unsigned low, signed high, signed low]
function getNybbles(b) { return [b >> 4, b & 15, uNybToSnyb[b >> 4], uNybToSnyb[b & 15]] }
function s16Tou8(i) { return ((i >>> 8)) + 128 }
function u16Tos16(i) { return (i > 32767) ? i - 65536 : i }
function checkIfPlayable() {
if (pcmType != 1) return `PCM Type not LPCM (${pcmType})`
if (pcmType != 1 && pcmType != 2) return `PCM Type not LPCM/ADPCM (${pcmType})`
if (nChannels != 2) return `Audio not stereo but instead has ${nChannels} channels`
if (samplingRate != 30000) return `Sampling rate is not 30000: ${samplingRate}`
if (pcmType != 1 && samplingRate != HW_SAMPLING_RATE) return `Format is ADPCM but sampling rate is not ${HW_SAMPLING_RATE}: ${samplingRate}`
return "playable!"
}
function decodeInfilePcm(inPtr, outPtr, inputLen) {
// LPCM
if (1 == pcmType) {
let bytes = bitsPerSample / 8
if (2 == bytes) {
for (let k = 0; k < inputLen / 2; k++) {
let s8 = sys.peek(inPtr + k*2 + 1) & 255
let u8 = s8 + 128
sys.poke(outPtr + k, u8)
}
function decodeLPCM(inPtr, outPtr, inputLen) {
let bytes = bitsPerSample / 8
if (2 == bytes) {
if (HW_SAMPLING_RATE == samplingRate) {
for (let k = 0; k < inputLen / 2; k++) {
sys.poke(outPtr + k, s16Tou8(sys.peek(inPtr + k*2 + 1)))
}
return inputLen / 2
}
// resample!
else {
throw Error(`24-bit or 32-bit PCM not supported (bits per sample: ${bitsPerSample})`)
// for rate 44100 16 bits, the inputLen will be 8232, if EOF not reached; otherwise pad with zero
let indexStride = samplingRate / HW_SAMPLING_RATE // note: a sample can span multiple bytes (2 for s16b)
let indices = (inputLen / indexStride) / nChannels / bytes
let sample = [
u16Tos16(sys.peek(inPtr+0) | (sys.peek(inPtr+1) << 8)),
u16Tos16(sys.peek(inPtr+2) | (sys.peek(inPtr+3) << 8))
]
printdbg(`indices: ${indices}; indexStride = ${indexStride}`)
// write out first sample
sys.poke(outPtr+0, s16Tou8(sample[0]))
sys.poke(outPtr+1, s16Tou8(sample[1]))
let sendoutLength = 2
for (let i = 1; i < indices; i++) {
for (let channel = 0; channel < nChannels; channel++) {
let iEnd = i * indexStride // sampleA, sampleB
let iA = iEnd|0
if (Math.abs((iEnd / iA) - 1.0) < 0.0001) {
// iEnd on integer point (no lerp needed)
let iR = Math.round(iEnd)
sample[channel] = u16Tos16(sys.peek(inPtr + 4*iR + 2*channel) | (sys.peek(inPtr + 4*iR + 2*channel + 1) << 8))
}
else {
// iEnd not on integer point (lerp needed)
// sampleA = samples[iEnd|0], sampleB = samples[1 + (iEnd|0)], lerpScale = iEnd - (iEnd|0)
// sample = lerp(sampleA, sampleB, lerpScale)
let sampleA = u16Tos16(sys.peek(inPtr + 4*iA + 2*channel + 0) | (sys.peek(inPtr + 4*iA + 2*channel + 1) << 8))
let sampleB = u16Tos16(sys.peek(inPtr + 4*iA + 2*channel + 4) | (sys.peek(inPtr + 4*iA + 2*channel + 5) << 8))
let scale = iEnd - iA
sample[channel] = (lerpAndRound(sampleA, sampleB, scale))
}
// soothing visualiser(????)
/*let ls = sample[0].toString(2)
if (sample[0] < 0)
ls = ls.padStart(16, ' ') + ' '
else
ls = ' ' + ls.padEnd(16, ' ')
let rs = sample[1].toString(2)
if (sample[1] < 0)
rs = rs.padStart(16, ' ') + ' '
else
rs = ' ' + rs.padEnd(16, ' ')
println(`${ls} | ${rs}`)*/
// writeout
sys.poke(outPtr + sendoutLength, s16Tou8(sample[channel]))
sendoutLength += 1
}
}
// pad with zero (might have lost the last sample of the input audio but whatever)
for (let k = 0; k < sendoutLength % nChannels; k++) {
sys.poke(outPtr + sendoutLength, 0)
sendoutLength += 1
}
return sendoutLength // for full chunk, this number should be equal to indices * 2
}
}
else {
throw Error(`PCM Type not LPCM or ADPCM (${pcmType})`)
throw Error(`24-bit or 32-bit PCM not supported (bits per sample: ${bitsPerSample})`)
}
}
// @see https://wiki.multimedia.cx/index.php/Microsoft_ADPCM
// @see https://github.com/Snack-X/node-ms-adpcm/blob/master/index.js
function decodeMS_ADPCM(inPtr, outPtr, blockSize) {
const adaptationTable = [
230, 230, 230, 230, 307, 409, 512, 614,
768, 614, 512, 409, 307, 230, 230, 230
]
const coeff1 = [256, 512, 0, 192, 240, 460, 392]
const coeff2 = [ 0,-256, 0, 64, 0,-208,-232]
if (2 == nChannels) {
let predictorL = sys.peek(inPtr + 0)
// if (predictorL < 0 || predictorR > 6) throw Error(`undefined predictorL ${predictorL}`)
let coeffL1 = coeff1[predictorL]
let coeffL2 = coeff2[predictorL]
let predictorR = sys.peek(inPtr + 1)
// if (predictorR < 0 || predictorR > 6) throw Error(`undefined predictorR ${predictorR}`)
let coeffR1 = coeff1[predictorR]
let coeffR2 = coeff2[predictorR]
let deltaL = sys.peek(inPtr + 2) | (sys.peek(inPtr + 3) << 8)
let deltaR = sys.peek(inPtr + 4) | (sys.peek(inPtr + 5) << 8)
// write initial two samples
let samL1 = u16Tos16(sys.peek(inPtr + 6) | (sys.peek(inPtr + 7) << 8))
let samR1 = u16Tos16(sys.peek(inPtr + 8) | (sys.peek(inPtr + 9) << 8))
let samL2 = u16Tos16(sys.peek(inPtr + 10) | (sys.peek(inPtr + 11) << 8))
let samR2 = u16Tos16(sys.peek(inPtr + 12) | (sys.peek(inPtr + 13) << 8))
sys.poke(outPtr + 0, s16Tou8(samL2))
sys.poke(outPtr + 1, s16Tou8(samR2))
sys.poke(outPtr + 2, s16Tou8(samL1))
sys.poke(outPtr + 3, s16Tou8(samR1))
let bytesSent = 4
// start delta-decoding
for (let curs = 14; curs < blockSize; curs++) {
let byte = sys.peek(inPtr + curs)
let [unybL, unybR, snybL, snybR] = getNybbles(byte)
// predict
predictorL = clampS16(((samL1 * coeffL1 + samL2 * coeffL2) >> 8) + (snybL * deltaL))
predictorR = clampS16(((samR1 * coeffR1 + samR2 * coeffR2) >> 8) + (snybR * deltaR))
// sendout
sys.poke(outPtr + bytesSent, s16Tou8(predictorL));bytesSent += 1;
sys.poke(outPtr + bytesSent, s16Tou8(predictorR));bytesSent += 1;
// shift samples
samL2 = samL1
samL1 = predictorL
samR2 = samR1
samR1 = predictorR
// compute next adaptive scale factor
deltaL = (deltaL * adaptationTable[unybL]) >> 8
deltaR = (deltaR * adaptationTable[unybR]) >> 8
// saturate delta to lower bound of 16
if (deltaL < 16) deltaL = 16
if (deltaR < 16) deltaR = 16
}
return bytesSent
}
else {
throw Error(`Only stereo sound decoding is supported (channels: ${nCHannels})`)
}
}
// @return decoded sample length (not count!)
function decodeInfilePcm(inPtr, outPtr, inputLen) {
// LPCM
if (1 == pcmType)
return decodeLPCM(inPtr, outPtr, inputLen)
else if (2 == pcmType)
return decodeMS_ADPCM(inPtr, outPtr, inputLen)
else
throw Error(`PCM Type not LPCM or ADPCM (${pcmType})`)
}
// read chunks loop
while (readCount < FILE_SIZE - 8) {
let chunkName = readFourCC()
@@ -203,12 +359,22 @@ while (readCount < FILE_SIZE - 8) {
bitsPerSample = readShort()
discardBytes(chunkSize - 16)
// define BLOCK_SIZE as integer multiple of blockSize
while (BLOCK_SIZE < 4096) {
BLOCK_SIZE += blockSize
// define BLOCK_SIZE as integer multiple of blockSize, for LPCM
// ADPCM will be decoded per-block basis
if (1 == pcmType) {
// get GCD of given values; this wll make resampling headache-free
let blockSizeIncrement = LCM(blockSize, samplingRate / GCD(samplingRate, HW_SAMPLING_RATE))
while (BLOCK_SIZE < 4096) {
BLOCK_SIZE += blockSizeIncrement // for rate 44100, BLOCK_SIZE will be 4116
}
INFILE_BLOCK_SIZE = BLOCK_SIZE * bitsPerSample / 8 // for rate 44100, INFILE_BLOCK_SIZE will be 8232
}
else if (2 == pcmType) {
BLOCK_SIZE = blockSize
INFILE_BLOCK_SIZE = BLOCK_SIZE
}
INFILE_BLOCK_SIZE = BLOCK_SIZE * bitsPerSample / 8
printdbg(`BLOCK_SIZE=${BLOCK_SIZE}, INFILE_BLOCK_SIZE=${INFILE_BLOCK_SIZE}`)
}
@@ -263,11 +429,11 @@ while (readCount < FILE_SIZE - 8) {
readBytes(readLength, readPtr)
let decodedSampleCount = decodeInfilePcm(readPtr, decodePtr, readLength)
printdbg(` decodedSampleCount: ${decodedSampleCount}`)
let decodedSampleLength = decodeInfilePcm(readPtr, decodePtr, readLength)
printdbg(` decodedSampleLength: ${decodedSampleLength}`)
audio.putPcmDataByPtr(decodePtr, decodedSampleCount, 0)
audio.setSampleUploadLength(0, decodedSampleCount)
audio.putPcmDataByPtr(decodePtr, decodedSampleLength, 0)
audio.setSampleUploadLength(0, decodedSampleLength)
audio.startSampleUpload(0)
if (repeat > 1) sys.sleep(10)