lili/data-over-audio
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remove packet size prefix from packet

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This commit is contained in:
Lewis Moten
2024-05-07 16:00:21 -04:00
parent fc9de6b6d3
commit 6bddb95f6e
2 changed files with 12 additions and 48 deletions
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1
index.html
View File

@@ -35,7 +35,6 @@
<h2>Decoded</h2>
<div class="raw-data" id="decoded-data"></div><br />
Error Percent: <span id="decoded-data-error-percent">N/A</span>%<br />
Data Byte Count: <span id="decoded-byte-count">N/A</span><br />
</div>
<div>
<h2>Decoded Text</h2>

59
index.js
View File

@@ -185,9 +185,9 @@ function handleTextToSendInput() {
const text = textToSend.value;
const dataByteCount = text.length;
const dataBitCount = dataByteCount * 8;
const nibblesToEncode = HAMMING_ERROR_CORRECTION ? Math.ceil((dataBitCount + PACKET_SIZE_BITS) / 4) : 0;
const nibblesToEncode = HAMMING_ERROR_CORRECTION ? Math.ceil((dataBitCount) / 4) : 0;
const errorCorrectionBits = nibblesToEncode * 3;
const totalBits = errorCorrectionBits + dataBitCount + PACKET_SIZE_BITS;
const totalBits = errorCorrectionBits + dataBitCount;
const totalBytes = Math.ceil(totalBits / 8);
const channelCount = getChannels().length;
const segmentCount = Math.ceil(totalBits / channelCount);
@@ -202,7 +202,7 @@ function handleTextToSendInput() {
document.getElementById('packet-send-channel-count').innerText = channelCount.toLocaleString();
document.getElementById('packet-send-segment-count').innerText = segmentCount.toLocaleString();
document.getElementById('packet-send-segment-duration').innerText = (SEGMENT_DURATION / 1000).toLocaleString();
document.getElementById('data-size-header-bits').innerText = PACKET_SIZE_BITS.toLocaleString();
document.getElementById('data-size-header-bits').innerText = '0';
}
function updateFrequencyResolution() {
@@ -461,14 +461,6 @@ function sendBits(bits) {
return;
}
const packetLength = ((byteCount - 1) >>> 0)
.toString(2)
.padStart(PACKET_SIZE_BITS, '0')
.split('')
.map(Number);
bits.unshift(...packetLength);
EXPECTED_BITS = bits.slice();
document.getElementById('sent-data').value = bits.reduce(bitReducer, '');
@@ -565,6 +557,7 @@ function collectSample() {
// we already have this sample
if(time === frequencyOverTime[0].time) return;
}
const channelCount = getChannels().length;
const frequencies = new Uint8Array(analyser.frequencyBinCount);
analyser.getByteFrequencyData(frequencies);
const length = audioContext.sampleRate / analyser.fftSize;
@@ -593,11 +586,15 @@ function collectSample() {
// proposed end
data.streamEnded = priorStreamEnded;
} else {
const totalBits = 2 ** PACKET_SIZE_BITS;
const segments = Math.ceil(totalBits / channelCount);
const duration = segments * SEGMENT_DURATION;
if(pauseTimeoutId) {
window.clearTimeout(pauseTimeoutId);
pauseTimeoutId = undefined;
// recover prior bit stream
data.streamStarted = LAST_STREAM_STARTED;
data.streamEnded = LAST_STREAM_STARTED + duration;
} else {
// new bit stream
data.streamStarted = time;
@@ -606,6 +603,7 @@ function collectSample() {
packetReceivedBits.length = 0;
packetUninterlievedBits.length = 0;
packetDataByteCount = 0;
data.streamEnded = time + duration;
}
}
@@ -698,7 +696,6 @@ if((sampleDuration / SEGMENT_DURATION) < LAST_SEGMENT_PERCENT) return;
packetReceivedBits.push(...bitValues);
packetUninterlievedBits.push(...removeInterleaving(bitValues));
const encodingRatio = HAMMING_ERROR_CORRECTION ? ERROR_CORRECTION_BLOCK_SIZE/4 : 1;
if(HAMMING_ERROR_CORRECTION) {
packetDecodedBits.length = 0;
for(let i = 0; i < packetUninterlievedBits.length; i += ERROR_CORRECTION_BLOCK_SIZE) {
@@ -711,38 +708,6 @@ if((sampleDuration / SEGMENT_DURATION) < LAST_SEGMENT_PERCENT) return;
packetDecodedBits.push(...packetUninterlievedBits);
}
// Determine if we can identify the length of data comming
const encodedBitsNeededForDataLength = Math.ceil(Math.ceil(PACKET_SIZE_BITS / 4) * encodingRatio);
if(packetDecodedBits.length >= encodedBitsNeededForDataLength) {
// we can evaluate when we should know many bytes are comming
const dataLengthIndex = Math.floor(encodedBitsNeededForDataLength / channelCount);
// if(dataLengthIndex === segmentIndex) {
// we just got the bits we needed
packetDataByteCount = 1 + packetDecodedBits
.slice(0, PACKET_SIZE_BITS)
.reduce((value, bit) => (value << 1) | bit);
document.getElementById('decoded-byte-count').innerText = packetDataByteCount;
// let's get the end time
const totalBits = Math.ceil(((packetDataByteCount * 8) + PACKET_SIZE_BITS) * encodingRatio);
const segments = Math.ceil(totalBits / channelCount);
const duration = segments * SEGMENT_DURATION;
const streamEnded = streamStarted + duration;
// update everyones proposed end time
frequencyOverTime
.filter(fot => fot.streamStarted === streamStarted)
.forEach(fot => {
fot.streamEnded = streamEnded
});
// }
// remove phantom bits
// const totalBits = Math.ceil(((packetDataByteCount * 8) + PACKET_SIZE_BITS) * encodingRatio);
if(packetReceivedBits.length > totalBits) {
// const excess = packetReceivedBits.length % totalBits;
// packetReceivedBits.length = totalBits;
// bitValues.length = bitValues.length - excess;
}
}
document.getElementById('decoded-data').innerHTML = packetDecodedBits.reduce(bitExpectorReducer(EXPECTED_BITS), '');
document.getElementById('received-data').innerHTML = packetReceivedBits.reduce(bitExpectorReducer(EXPECTED_ENCODED_BITS), '');
@@ -779,14 +744,14 @@ const bitExpectorReducer = expected => (all, bit, i) => {
}
const textExpectorReducer = expected => (all, bit, i, bits) => {
if(i < PACKET_SIZE_BITS) return all;
if((i - PACKET_SIZE_BITS) % 8 === 0) {
if(i % 8 === 0) {
const bitString = bits.slice(
i,
i + 8
).join('').padEnd(8, '0');
const ascii = parseInt(bitString, 2);
const char = String.fromCharCode(ascii);
const charIndex = Math.floor((i - PACKET_SIZE_BITS) / 8);
const charIndex = Math.floor(i / 8);
if(char !== expected[charIndex]) {
all += '<span class="bit-wrong">' + htmlEncode(printable(char)) + '</span>';
} else {
@@ -1121,7 +1086,7 @@ function getDataBitCount() {
return dataByteCount * 8;
}
function getPacketSizeUnencodedBitCount() {
return getDataBitCount() + PACKET_SIZE_BITS;
return getDataBitCount();
}
function getErrorCorrectionBlocks() {
if(!HAMMING_ERROR_CORRECTION) return 0;