Ansh rathod Ansh-Rathod

Reading waveform data in ffmpeg

When working on an audio player, I wanted to extract the audio waveform data to paint the audio waveform dynamically in the browser on a <canvas> element.

Initially I used the bbc/audiowaveform package but this proved problematic for a number of reasons. First I wasn't able to install that package (or build the binary) in macOS for local dev. The other big issue is that I was only able to figure out how to install it on Ubuntu, so I couldn't use it in Alpine (for Docker images) or other environments like cloud functions.

Initial approach

I found out from these docs it's possible to paint a waveform with ffmpeg by extracting raw audio data:

	import 'dart:async';

	import 'package:flutter/foundation.dart';
	import 'package:flutter/material.dart';
	import 'package:uri/uri.dart';

	class PathRouteMatch {
	PathRouteMatch(
	{required this.parameters,
	required this.route,

	import 'dart:collection';
	import 'dart:math';
	import 'dart:ui' as ui;

	import 'package:collection/collection.dart';
	import 'package:flutter/material.dart';

	// TODO
	// * check if [radius] / [radii] are not too big?
	// * use [Path.arcToPoint] so [radius] (and [radii]) can be specified as [Radius]

	import 'package:flutter/material.dart';
	import 'package:flutter_riverpod/flutter_riverpod.dart';
	import 'package:dio/dio.dart';

	// Disclaimer: This uses the "The Movie Database API (TMDB)"
	// https://developers.themoviedb.org/3/getting-started
	// With this endpoint:
	// https://developers.themoviedb.org/3/people/get-popular-people

	/// The FutureProvider that does the fetching of the paginated list of people