deepvoice_client/local_plugins/opus/lib/opus.dart

import 'dart:async';
import 'dart:typed_data';

import 'package:flutter/services.dart';

/// Opus 音频格式的应用类型
class OpusApplicationType {
  /// 通用音频编码 (OPUS_APPLICATION_AUDIO)
  static const int audio = 2048;
  
  /// 语音编码 (OPUS_APPLICATION_VOIP)
  static const int voip = 2048;
  
  /// 低延迟编码 (OPUS_APPLICATION_RESTRICTED_LOWDELAY)
  static const int restrictedLowDelay = 2051;
}

/// Opus 编解码插件，提供对 Opus 音频格式的编码和解码功能
class Opus {
  static const MethodChannel _channel = MethodChannel('com.yunqiinnovation.opus');
  
  /// 创建 Opus 编码器实例
  /// 
  /// [sampleRate] 采样率 (Hz)，常用值：8000, 16000, 24000, 48000
  /// [channels] 声道数，1=单声道，2=立体声
  /// [application] 应用类型，默认为音频编码 [OpusApplicationType.audio]
  /// [complexity] 复杂度 (0-10)，数值越高质量越好，但CPU占用也更高
  /// [frameSize] 编码帧大小，常用值：120, 240, 480, 960, 2880
  /// 
  /// 返回创建是否成功
  static Future<bool> createEncoder({
    int sampleRate = 48000,
    int channels = 2,
    int application = OpusApplicationType.audio,
    int complexity = 10,
    int frameSize = 960,
  }) async {
    try {
      final bool? success = await _channel.invokeMethod<bool>('createEncoder', {
        'sampleRate': sampleRate,
        'channels': channels,
        'application': application,
        'complexity': complexity,
        'frameSize': frameSize,
      });
      return success ?? false;
    } on PlatformException catch (e) {
      print('Failed to create Opus encoder: ${e.message}');
      return false;
    }
  }
  
  /// 创建 Opus 解码器实例
  /// 
  /// [sampleRate] 采样率 (Hz)，常用值：8000, 16000, 24000, 48000
  /// [channels] 声道数，1=单声道，2=立体声
  /// 
  /// 返回创建是否成功
  static Future<bool> createDecoder({
    int sampleRate = 48000,
    int channels = 2,
  }) async {
    try {
      final bool? success = await _channel.invokeMethod<bool>('createDecoder', {
        'sampleRate': sampleRate,
        'channels': channels,
      });
      return success ?? false;
    } on PlatformException catch (e) {
      print('Failed to create Opus decoder: ${e.message}');
      return false;
    }
  }
  
  /// 编码 PCM 数据为 Opus 格式
  /// 
  /// [pcmData] 16位 PCM 音频数据
  /// 
  /// 返回编码后的 Opus 数据，如果失败返回 null
  static Future<Uint8List?> encodeData(Uint8List pcmData) async {
    try {
      final result = await _channel.invokeMethod<Uint8List>('encodeData', {
        'input': pcmData,
      });
      return result;
    } on PlatformException catch (e) {
      print('Failed to encode data: ${e.message}');
      return null;
    }
  }
  
  /// 解码 Opus 数据为 PCM 格式
  /// 
  /// [opusData] Opus 编码数据
  /// [frameSize] 解码帧大小，需要与编码时使用的帧大小匹配
  /// 
  /// 返回解码后的 PCM 数据，如果失败返回 null
  static Future<Uint8List?> decodeData(Uint8List opusData, {int frameSize = 960}) async {
    try {
      final result = await _channel.invokeMethod<Uint8List>('decodeData', {
        'input': opusData,
        'frameSize': frameSize,
      });
      return result;
    } on PlatformException catch (e) {
      print('Failed to decode data: ${e.message}');
      return null;
    }
  }
  
  /// 释放编码器资源
  static Future<void> disposeEncoder() async {
    try {
      await _channel.invokeMethod<void>('disposeEncoder');
    } on PlatformException catch (e) {
      print('Failed to dispose encoder: ${e.message}');
    }
  }
  
  /// 释放解码器资源
  static Future<void> disposeDecoder() async {
    try {
      await _channel.invokeMethod<void>('disposeDecoder');
    } on PlatformException catch (e) {
      print('Failed to dispose decoder: ${e.message}');
    }
  }
}