imterah/element-portable
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Adjust recording waveform behaviour for voice messages

Browse source 
Fixes https://github.com/vector-im/element-web/issues/17683
This commit is contained in:
Travis Ralston 2021-07-12 13:48:01 -06:00
parent 1b39dbdb53
commit ec0f940ef0
5 changed files with 148 additions and 49 deletions
Download patch file Download diff file Expand all files Collapse all files

27
src/voice/RecorderWorklet.ts
View file

@ -22,14 +22,29 @@ declare const currentTime: number;
// declare const currentFrame: number;
// declare const sampleRate: number;
// We rate limit here to avoid overloading downstream consumers with amplitude information.
// The two major consumers are the voice message waveform thumbnail (resampled down to an
// appropriate length) and the live waveform shown to the user. Effectively, this controls
// the refresh rate of that live waveform and the number of samples the thumbnail has to
// work with.
const TARGET_AMPLITUDE_FREQUENCY = 16; // Hz
function roundTimeToTargetFreq(seconds: number): number {
// Epsilon helps avoid floating point rounding issues (1 + 1 = 1.999999, etc)
return Math.round((seconds + Number.EPSILON) * TARGET_AMPLITUDE_FREQUENCY) / TARGET_AMPLITUDE_FREQUENCY;
}
function nextTimeForTargetFreq(roundedSeconds: number): number {
// The extra round is just to make sure we cut off any floating point issues
return roundTimeToTargetFreq(roundedSeconds + (1 / TARGET_AMPLITUDE_FREQUENCY));
}
class MxVoiceWorklet extends AudioWorkletProcessor {
private nextAmplitudeSecond = 0;
private amplitudeIndex = 0;
process(inputs, outputs, parameters) {
// We only fire amplitude updates once a second to avoid flooding the recording instance
// with useless data. Much of the data would end up discarded, so we ratelimit ourselves
// here.
const currentSecond = Math.round(currentTime);
const currentSecond = roundTimeToTargetFreq(currentTime);
if (currentSecond === this.nextAmplitudeSecond) {
// We're expecting exactly one mono input source, so just grab the very first frame of
// samples for the analysis.
@ -47,9 +62,9 @@ class MxVoiceWorklet extends AudioWorkletProcessor {
this.port.postMessage(<IAmplitudePayload>{
ev: PayloadEvent.AmplitudeMark,
amplitude: amplitude,
forSecond: currentSecond,
forIndex: this.amplitudeIndex++,
});
this.nextAmplitudeSecond++;
this.nextAmplitudeSecond = nextTimeForTargetFreq(currentSecond);
}
// We mostly use this worklet to fire regular clock updates through to components