lili/data-over-audio
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send data over multiple packets

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This commit is contained in:
Lewis Moten
2024-05-07 22:59:51 -04:00
parent 6bddb95f6e
commit bc26da11f3
2 changed files with 277 additions and 89 deletions
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17
index.html
View File

@@ -19,6 +19,23 @@
<button id="send-button">Send</button><br />
<textarea id="sent-data" rows="10" cols="40"></textarea><br />
</div>
<div>
<h2>Data</h2>
Data Bytes: <span id="data-byte-count"></span><br>
Data Bits: <span id="data-bit-count"></span><br>
Bits per Packet: <span id="packet-bit-count"></span><br>
Data Bits per Packet: <span id="packet-data-bit-count"></span><br>
Error Correction: <span id="packet-error-correction"></span><br>
Error Blocks per packet: <span id="packet-error-block-count"></span><br>
Unused bits per packet: <span id="packet-unused-bit-count"></span><br>
Unused bits in last packet: <span id="last-packet-unused-bit-count"></span><br>
Last segment unused channels in packet: <span id="last-segment-unused-channel-count"></span><br>
Packet Count: <span id="packet-count"></span><br>
Segments Per Packet: <span id="segments-per-packet"></span><br>
Segment Duration: <span id="segment-transfer-duration"></span><br>
Packet Duration: <span id="packet-transfer-duration"></span><br>
Total Duration: <span id="data-transfer-duration"></span><br>
</div>
<div>
<h2>Encoded</h2>
<textarea id="encoded-data" rows="10" cols="40"></textarea><br />

349
index.js
View File

@@ -34,6 +34,7 @@ let PERIODIC_INTERLEAVING = true;
let WAVE_FORM = "triangle";
const ERROR_CORRECTION_BLOCK_SIZE = 7;
const ERROR_CORRECTION_DATA_SIZE = 4;
let CHANNEL_OVER = -1;
let CHANNEL_SELECTED = -1;
let SEGMENT_OVER = -1;
@@ -49,7 +50,7 @@ var samplesPerBit = [];
var bitSampleCount = 0;
var PAUSE = false;
var PAUSE_AFTER_END = true;
var PACKET_SIZE_BITS = 8;
var PACKET_SIZE_BITS = 5; // 32 bytes, 256 bits
var EXPECTED_ENCODED_BITS = [];
var EXPECTED_BITS = [];
@@ -87,6 +88,7 @@ function handleWindowLoad() {
document.getElementById('packet-size-power').addEventListener('input', event => {
PACKET_SIZE_BITS = parseInt(event.target.value);
document.getElementById('packet-size').innerText = friendlyByteSize(2 ** PACKET_SIZE_BITS);
showSpeed();
});
document.getElementById('pause-after-end').checked = PAUSE_AFTER_END;
document.getElementById('error-correction-hamming').checked = HAMMING_ERROR_CORRECTION;
@@ -185,7 +187,7 @@ function handleTextToSendInput() {
const text = textToSend.value;
const dataByteCount = text.length;
const dataBitCount = dataByteCount * 8;
const nibblesToEncode = HAMMING_ERROR_CORRECTION ? Math.ceil((dataBitCount) / 4) : 0;
const nibblesToEncode = HAMMING_ERROR_CORRECTION ? Math.ceil((dataBitCount) / ERROR_CORRECTION_DATA_SIZE) : 0;
const errorCorrectionBits = nibblesToEncode * 3;
const totalBits = errorCorrectionBits + dataBitCount;
const totalBytes = Math.ceil(totalBits / 8);
@@ -203,6 +205,7 @@ function handleTextToSendInput() {
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 = '0';
updatePacketStats();
}
function updateFrequencyResolution() {
@@ -228,7 +231,7 @@ function showSpeed() {
document.getElementById('data-transfer-speed-bits-per-second').innerText = baud.toFixed(2);
document.getElementById('data-transfer-speed-bytes-per-second').innerText = bytes.toFixed(2);
if(HAMMING_ERROR_CORRECTION) {
const effectiveBaud = baud * 4 / ERROR_CORRECTION_BLOCK_SIZE;
const effectiveBaud = baud * ERROR_CORRECTION_DATA_SIZE / ERROR_CORRECTION_BLOCK_SIZE;
const effectiveBytes = effectiveBaud / 8;
document.getElementById('effective-speed-bits-per-second').innerText = effectiveBaud.toFixed(2);
document.getElementById('effective-speed-bytes-per-second').innerText = effectiveBytes.toFixed(2);
@@ -263,6 +266,25 @@ function showSpeed() {
})
handleTextToSendInput();
drawChannels();
updatePacketStats();
}
function updatePacketStats() {
const text = textToSend.value;
const bits = textToBits(text);
document.getElementById('data-byte-count').innerText = (bits.length / 8).toLocaleString();
document.getElementById('data-bit-count').innerText = bits.length.toLocaleString();
document.getElementById('packet-bit-count').innerText = getPacketBitCount().toLocaleString();
document.getElementById('packet-count').innerText = getPacketCount(bits).toLocaleString();
document.getElementById('packet-error-correction').innerText = HAMMING_ERROR_CORRECTION ? 'Yes' : 'No';
document.getElementById('packet-error-block-count').innerText = getPacketErrorBlockCount().toLocaleString();
document.getElementById('packet-data-bit-count').innerText = getPacketDataBitCount().toLocaleString();
document.getElementById('packet-unused-bit-count').innerText = getPacketUnusedBitCount().toLocaleString();
document.getElementById('last-packet-unused-bit-count').innerText = getPacketLastUnusedBitCount(bits).toLocaleString();
document.getElementById('last-segment-unused-channel-count').innerText = getPacketLastSegmentUnusedChannelCount().toLocaleString()
document.getElementById('packet-transfer-duration').innerText = getPacketDurationSeconds(bits).toLocaleString() + 's';
document.getElementById('segment-transfer-duration').innerText = getSegmentTransferDurationSeconds().toLocaleString() + 's';
document.getElementById('data-transfer-duration').innerText = getDataTransferDurationSeconds(bits).toLocaleString() + 's';
document.getElementById('segments-per-packet').innerText = getPacketSegmentCount().toLocaleString();
}
function drawChannels() {
const sampleRate = getAudioContext().sampleRate;
@@ -323,7 +345,7 @@ function percentInFrequency(hz, frequencyResolution) {
return percent;
}
function nibbleToHamming(nibble) {
if(nibble.length !== 4) return [];
if(nibble.length !== ERROR_CORRECTION_DATA_SIZE) return [];
return [
nibble[0] ^ nibble[1] ^ nibble[3],
nibble[0] ^ nibble[2] ^ nibble[3],
@@ -414,10 +436,10 @@ function staggerValues(values, blockSize, undo) {
function applyErrorCorrection(bits) {
if(!HAMMING_ERROR_CORRECTION) return bits;
const encodedBits = [];
for(let i = 0; i < bits.length; i+= 4) {
const nibble = bits.slice(i, i + 4);
while(nibble.length < 4) nibble.push(0);
encodedBits.push(...nibbleToHamming(bits.slice(i, i + 4)));
for(let i = 0; i < bits.length; i+= ERROR_CORRECTION_DATA_SIZE) {
const nibble = bits.slice(i, i + ERROR_CORRECTION_DATA_SIZE);
while(nibble.length < ERROR_CORRECTION_DATA_SIZE) nibble.push(0);
encodedBits.push(...nibbleToHamming(bits.slice(i, i + ERROR_CORRECTION_DATA_SIZE)));
}
return encodedBits;
}
@@ -449,77 +471,247 @@ function logSent(text) {
sentDataTextArea.scrollTop = sentDataTextArea.scrollHeight;
}
function sendBits(bits) {
const byteCount = bits.length / 8;
if(bits.length === 0) {
logSent('No bits to send!');
return;
} else if(bits.length % 8 !== 0 || bits.length === 0) {
logSent('Bit count must be divisible by 8.');
return;
} else if(byteCount > (1 << PACKET_SIZE_BITS)) {
logSent(`Can not transfer more than ${(1 << PACKET_SIZE_BITS)} bytes.`);
return;
}
const channelCount = getChannels().length;
EXPECTED_BITS = bits.slice();
document.getElementById('sent-data').value = bits.reduce(bitReducer, '');
EXPECTED_ENCODED_BITS = bits = applyInterleaving(
applyErrorCorrection(bits)
EXPECTED_ENCODED_BITS = [];
const startSeconds = audioContext.currentTime + 0.1;
const startMilliseconds = startSeconds * 1000;
const packetCount = getPacketCount(bits);
const packetBitCount = getPacketBitCount();
const totalDurationSeconds = getDataTransferDurationSeconds(bits);
const totalDurationMilliseconds = getDataTransferDurationSeconds(bits);
const packetDurationSeconds = getPacketDurationSeconds();
sendButton.innerText = 'Stop';
createOscillators(startSeconds);
// send all packets
for(let i = 0; i < packetCount; i++) {
let packet = getPacketBits(bits, i);
if(packet.length > packetBitCount) {
console.error('cant send packet of %s bits with more than %s bits', packet.length, packetBitCount);
disconnectOscillators();
return;
}
packet = applyInterleaving(packet);
EXPECTED_ENCODED_BITS.push(...packet);
sendPacket(packet, startSeconds + (i * packetDurationSeconds));
}
stopOscillators(startSeconds + totalDurationSeconds);
stopTimeoutId = window.setTimeout(
disconnectOscillators,
startMilliseconds + totalDurationMilliseconds
);
document.getElementById('encoded-data').value = EXPECTED_ENCODED_BITS.reduce(bitReducer, '');
var audioContext = getAudioContext();
const channels = getChannels();
const oscillators = [];
const channelCount = channels.length;
const currentTime = audioContext.currentTime + 0.1;
const destination = SEND_VIA_SPEAKER ? audioContext.destination : getAnalyser();
// create our oscillators
for(let i = 0; i < channelCount; i++) {
var oscillator = audioContext.createOscillator();
oscillator.connect(destination);
oscillator.type = WAVE_FORM;
oscillators.push(oscillator);
}
// change our channel frequencies for the bit
for(let i = 0; i < bits.length; i++) {
const isHigh = bits[i];
const channel = i % channelCount;
const segment = Math.floor(i / channelCount);
var offset = ((segment * SEGMENT_DURATION)/1000);
var offset2 = (((segment+1) * SEGMENT_DURATION)/1000) - (1/100000);
oscillators[channel].frequency.setValueAtTime(
channels[channel][isHigh ? 1 : 0],
currentTime + offset
);
oscillators[channel].frequency.setValueAtTime(
channels[channel][isHigh ? 1 : 0],
currentTime + offset2
);
}
// start sending our signal
oscillators.forEach(o => o.start(currentTime));
// silence oscillators when done
for(let i = bits.length; i < bits.length + channelCount; i++) {
const channel = i % channelCount;
const segment = Math.floor(i / channelCount);
const offset = ((segment * SEGMENT_DURATION) / 1000);
oscillators[channel].frequency.setValueAtTime(0, currentTime + offset);
oscillators[channel].stop(currentTime + offset);
}
// start the graph moving again
resumeGraph();
}
let stopTimeoutId;
function getDataTransferDurationMilliseconds(bits) {
return getPacketCount(bits) * getPacketDurationMilliseconds();
}
function getDataTransferDurationSeconds(bits) {
return getDataTransferDurationMilliseconds(bits) / 1000;
}
function getPacketDurationMilliseconds() {
return getPacketSegmentCount() * SEGMENT_DURATION;
}
function getPacketDurationSeconds() {
return getPacketDurationMilliseconds() / 1000;
}
function getSegmentTransferDurationSeconds() {
return SEGMENT_DURATION / 1000;
}
function getPacketSegmentCount() {
return Math.ceil(getPacketBitCount() / getChannels().length);
}
function getPacketCount(bits) {
if(!canSendPacket()) return 0;
// How many data bits will be encoded in our packet?
let dataBitCount = getPacketDataBitCount();
// Return the total number of packets needed to send all data
return Math.ceil(bits.length / dataBitCount);
}
function getPacketBits(bits, packetIndex) {
if(!canSendPacket()) return [];
const packetBits = getPacketUsedBits(bits, packetIndex);
// How many bits expected in our packet?
const packetBitCount = getPacketBitCount();
// pad the array to the entire packet size
return padArray(packetBits, packetBitCount, 0);
}
function getPacketUsedBits(bits, packetIndex) {
if(!canSendPacket()) return [];
// How many data bits will be in our packet?
const dataBitCount = getPacketDataBitCount();
// grab our data
const startIndex = packetIndex * dataBitCount;
const endIndex = startIndex + dataBitCount;
let packetBits = bits.slice(startIndex, endIndex);
// Are we using error correction?
if(HAMMING_ERROR_CORRECTION) {
// encode data bits
packetBits = applyErrorCorrection(packetBits);
}
return packetBits;
}
function getPacketErrorBlockCount() {
const bitCount = getPacketBitCount();
// No error correction?
if(!HAMMING_ERROR_CORRECTION) {
// No error blocks
return 0;
}
// How many error blocks can be in a packet?
return Math.floor(
bitCount /
ERROR_CORRECTION_BLOCK_SIZE
);
}
function getPacketByteCount() {
// Convert packet size as power of 2
return 2 ** PACKET_SIZE_BITS;
}
function getPacketBitCount() {
// 8 bits per byte
return getPacketByteCount() * 8;
}
function canSendPacket() {
const max = getPacketBitCount();
// Need at least 1 bit to send
if(max < 1) return false;
// Has error correction?
if(HAMMING_ERROR_CORRECTION) {
// Need enough bits to fit one or more blocks
return max >= ERROR_CORRECTION_BLOCK_SIZE;
}
// 1 or more is great without encoding
return true;
}
function getPacketLastSegmentUnusedChannelCount() {
const channelCount = getChannels().length;
return (channelCount - (getPacketBitCount() % channelCount));
}
function getPacketUnusedBitCount() {
return getPacketBitCount() - getPacketDataBitCount();
}
function getPacketLastUnusedBitCount(bits) {
const packetCount = getPacketCount(bits);
const availableBits = getPacketBitCount();
const usedBits = getPacketUsedBits(bits, packetCount-1).length;
return availableBits - usedBits;
}
function getPacketDataBitCount() {
const bitCount = getPacketBitCount();
// No error correction?
if(!HAMMING_ERROR_CORRECTION) {
// Return all bits available
return bitCount;
}
return getPacketErrorBlockCount() * ERROR_CORRECTION_DATA_SIZE;
}
function padArray(values, length, value) {
while(values.length < length) values.push(value);
return values;
}
const CHANNEL_OSCILLATORS = [];
function getOscillators() {
return CHANNEL_OSCILLATORS;
}
function createOscillators(streamStartSeconds) {
console.log('create oscillators', streamStartSeconds);
const oscillators = getOscillators();
if(oscillators.length !== 0) disconnectOscillators();
var audioContext = getAudioContext();
const channels = getChannels();
const channelCount = channels.length;
const destination = SEND_VIA_SPEAKER ? audioContext.destination : getAnalyser();
// create our oscillators
for(let i = 0; i < channelCount; i++) {
const oscillator = audioContext.createOscillator();
oscillator.connect(destination);
oscillator.type = WAVE_FORM;
oscillator.start(streamStartSeconds);
oscillators.push(oscillator);
}
return oscillators;
}
function disconnectOscillators() {
console.log('disconnect oscillators');
stopOscillators(getAudioContext().currentTime);
const oscillators = getOscillators();
oscillators.forEach(
oscillator => oscillator.disconnect()
)
oscillators.length = 0;
sendButton.innerText = 'Send';
stopTimeoutId = undefined;
}
function stopOscillators(streamEndSeconds) {
console.log('stop oscillators', streamEndSeconds);
const channels = getChannels();
const oscillators = getOscillators();
const channelCount = channels.length;
// silence oscillators when done
for(let channel = 0; channel < channelCount; channel++) {
const oscillator = oscillators[channel];
oscillator?.stop(streamEndSeconds);
}
}
function sendPacket(bits, packetStartSeconds) {
console.log('packet start', packetStartSeconds);
const channels = getChannels();
const oscillators = getOscillators();
const channelCount = channels.length;
let bitCount = bits.length;
const lastChannel = bits.length % channelCount;
if(lastChannel !== channelCount - 1) {
// make sure all channels are set for the last segment
bitCount += (channelCount - lastChannel)
}
const segmentDurationSeconds = getSegmentTransferDurationSeconds();
// change our channel frequencies for the bit
for(let i = 0; i < bitCount; i++) {
// missing bits past end of bit stream set to zero
const isHigh = bits[i] ?? 0;
const channel = i % channelCount;
// already at correct frequency
if(oscillators[channel].on === isHigh) continue;
oscillators[channel].on = isHigh;
const segmentIndex = Math.floor(i / channelCount);
var offsetSeconds = segmentIndex * segmentDurationSeconds;
oscillators[channel].frequency.setValueAtTime(
channels[channel][isHigh ? 1 : 0],
packetStartSeconds + offsetSeconds
);
}
}
function stopGraph() {
PAUSE = true;
stopCollectingSamples();
@@ -806,6 +998,10 @@ function textToBits(text) {
return bits.join('').split('').map(Number);
}
function handleSendButtonClick() {
if(stopTimeoutId) {
disconnectOscillators();
return;
}
receivedDataTextarea.value = '';
sentDataTextArea.value = '';
@@ -1080,37 +1276,12 @@ function getTimePercent(time, newest) {
if(newest - time > duration) return -1;
return ((newest - time) / duration);
}
function getDataBitCount() {
const text = document.getElementById('text-to-send').value;
const dataByteCount = text.length;
return dataByteCount * 8;
}
function getPacketSizeUnencodedBitCount() {
return getDataBitCount();
}
function getErrorCorrectionBlocks() {
if(!HAMMING_ERROR_CORRECTION) return 0;
const dataBitCount = getPacketSizeUnencodedBitCount();
return Math.ceil(dataBitCount / 4);
}
function getErrorCorrectionBitCount() {
return getErrorCorrectionBlocks() * 3;
}
function getPacketSizeEncodedBitCount() {
return getErrorCorrectionBitCount() + getPacketSizeUnencodedBitCount();
}
function getPacketSizeEncodedByteCount() {
return Math.ceil(getPacketSizeEncodedBitCount() / 8);
}
function getPacketSizeSegmentCount() {
const totalBits = getPacketSizeEncodedBitCount();
const totalBits = getPacketBitCount();
const channelCount = getChannels().length;
return Math.ceil(totalBits / channelCount);
}
function getPacketDurationMilliseconds() {
const segmentCount = getPacketSizeSegmentCount();
return segmentCount * SEGMENT_DURATION;
}
function drawChannelData() {
// Do/did we have a stream?
if(!LAST_STREAM_STARTED) return;
@@ -1118,7 +1289,7 @@ function drawChannelData() {
const latest = frequencyOverTime[0].time;
// will any of the stream appear?
const packetBitCount = getPacketSizeEncodedBitCount();
const packetBitCount = getPacketBitCount();
const packetDuration = getPacketDurationMilliseconds();
const lastStreamEnded = LAST_STREAM_STARTED + packetDuration;