OPUS Audio OGG/CAF Converter

Convert OPUS audio files between OGG (standard) and CAF (Apple) container formats using pure dart.

OPUS is a modern, leading audio codec that is widely used for audio streaming and storage due to its smaller file size without loss of quality. However, Apple does not conform to the standard OGG container spec for OPUS files, so it is difficult to use the OPUS codec when building cross-platform apps in Flutter/Dart. For example, iOS devices cannot play OPUS audio files in OGG format, and Android devices cannot play OPUS audio files in CAF format.

This package provides a simple way to convert OPUS audio files between OGG and CAF container formats (in either direction) using pure dart, without any external libraries or encoders.

Conversion is fast since the audio itself is not being re-encoded, but simply repackaged into a different container format. This means that the audio quality is not affected by the conversion, and speed is primarily limited by the file system I/O speed.

Features

• Converts OPUS audio files from OGG (standard spec) to CAF (Apple) container format.
• Converts OPUS audio files from CAF (Apple) to OGG (standard spec) container format.
• Lightweight, pure dart implementation.

Platform Support

Android	iOS	Web	Windows	Linux	MacOS
✅	✅	❓	❓	❓	❓

Testing on unknown platforms is welcome! Please file a GitHub issue if you determine how the package functions on another platform.

Getting started

Add the package to your pubspec.yaml file:

dart pub add ogg_caf_converter

or

flutter pub add ogg_caf_converter

Usage

To convert an OPUS audio file from a standard OGG container format to an Apple CAF container format, use the convertOggToCaf() method.

To convert an OPUS audio file from an Apple CAF container format to a standard OGG container format, use the convertCafToOgg() method.

Both functions take the same input parameters:

• input: The path to the input file (must have read access to this file path).
• output: The path to the output file (must have write access to this file path).
• deleteInput: Whether to delete the input file after successful conversion (must have write access to the input file path). Defaults to false.

For in-memory conversion without creating a new file, use the convertOggToCafInMemory() and convertCafToOggInMemory() methods. These functions return a Uint8List of the converted audio file bytes. Both functions take an input parameter of the input file path.

Example

Make sure to place the function call inside of a try-catch block to handle any exceptions, and await the function call to ensure the conversion is complete before continuing.

import 'dart:typed_data';

import 'package:ogg_caf_converter/ogg_caf_converter.dart';

const String inputFilePath = 'path/to/input/file.opus'; // Input file location
const String outputFilePath =
    'path/to/output/file.opus'; // Output file location

void main() async {
  // Convert from OGG to CAF
  try {
    await OggCafConverter().convertOggToCaf(
      input: inputFilePath,
      output: outputFilePath,
      deleteInput: true,
    );
  } catch (e) {
    // Handle error
  }

  // Convert from CAF to OGG
  try {
    await OggCafConverter().convertCafToOgg(
      input: inputFilePath,
      output: outputFilePath,
      deleteInput: true,
    );
  } catch (e) {
    // Handle error
  }

  // Convert from OGG to CAF in memory
  try {
    final Uint8List bytes = await OggCafConverter().convertOggToCafInMemory(
      input: inputFilePath,
    );
  } catch (e) {
    // Handle error
  }

  // Convert from CAF to OGG in memory
  try {
    final Uint8List bytes = await OggCafConverter().convertCafToOggInMemory(
      input: inputFilePath,
    );
  } catch (e) {
    // Handle error
  }
}

Issues

Please file any bugs or feature requests on the GitHub repository.