MediaExtractor MediaCodec手动解码播放音乐

MediaExtractor MediaCodec手动解码播放音乐,笔记

private class DecodeAudio implements Runnable {

        @Override
        public void run() {
            //开始播放pcm
            audioTrack.play();
            MediaExtractor extractor = null;
            MediaCodec codec = null;
            Log.i(TAG, "run: init");
            FileOutputStream fileOutputStream = null;
            try (AssetFileDescriptor assetFileDescriptor = context.getAssets().openFd("outfile3.mp3")) {
                Thread.sleep(300);
                Log.i(TAG, "run: start");
                extractor = new MediaExtractor();
                extractor.setDataSource(assetFileDescriptor);
                int trackIndex = selectAudioTrack(extractor); // 选择音频轨道（如果有多个）
                if (trackIndex == -1) {
                    extractor.release();
                    throw new Exception("没有音频轨道");
                }
                extractor.selectTrack(trackIndex); // 选择指定轨道

                Log.i(TAG, "run: 获取信息:" + trackIndex);
                MediaFormat format = extractor.getTrackFormat(trackIndex);
                Log.i(TAG, "run: 获取信息字段:" + format.toString());
                String mime = format.getString(MediaFormat.KEY_MIME);
                Log.i(TAG, "run: 创建解码器");
                codec = MediaCodec.createDecoderByType(mime);
                codec.configure(format, null, null, 0);
                codec.start();

                // start decode
                final int TIMEOUT_US = 10000; // 超时时间
                MediaCodec.BufferInfo info = new MediaCodec.BufferInfo();
                ByteBuffer[] inputBuffers = codec.getInputBuffers();
                ByteBuffer[] outputBuffers = codec.getOutputBuffers();

                Log.i(TAG, "run: start looper");
                fileOutputStream = new FileOutputStream(targetFile2);

                while (!isEndOfStream) {
                    int inputBufferIndex = codec.dequeueInputBuffer(TIMEOUT_US);
                    if (inputBufferIndex >= 0) {
                        Log.i(TAG, "run: 读取到数据了 :" + inputBufferIndex);
                        ByteBuffer inputBuffer = inputBuffers[inputBufferIndex];
                        int sampleSize = extractor.readSampleData(inputBuffer, 0);
                        if (sampleSize < 0) {
                            // 到达流的结束点
                            codec.queueInputBuffer(inputBufferIndex, 0, 0, 0, MediaCodec.BUFFER_FLAG_END_OF_STREAM);
                            isEndOfStream = true;
                        } else {
                            long presentationTimeUs = extractor.getSampleTime();
                            codec.queueInputBuffer(inputBufferIndex, 0, sampleSize, presentationTimeUs, 0);
                            extractor.advance();
                        }
                    }

                    Log.i(TAG, "run: 进入解码过程");

                    int outputBufferIndex = codec.dequeueOutputBuffer(info, TIMEOUT_US);
                    if (outputBufferIndex >= 0) {
                        Log.i(TAG, "run: 开始解码中：" + outputBufferIndex);
                        ByteBuffer outputBuffer = outputBuffers[outputBufferIndex];
                        byte[] pcmData = new byte[info.size];
                        outputBuffer.get(pcmData); // 获取PCM数据
                        Log.i(TAG, "run: pcm data:" + pcmData.length);
                        // 写入pcm
                        audioTrack.write(pcmData, 0, pcmData.length);
                        fileOutputStream.write(pcmData, 0, pcmData.length);
                        outputBuffer.clear();
                        codec.releaseOutputBuffer(outputBufferIndex, false);
                    }
                    Thread.sleep(2);
                }
                Log.i(TAG, "run: 成功解码");
            } catch (Exception e) {
                e.printStackTrace();
                Log.i(TAG, "run: error:" + e.getMessage());
            } finally {
                try {
                    Thread.sleep(288);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                if (fileOutputStream != null) {
                    try {
                        fileOutputStream.flush();
                        fileOutputStream.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
                if (codec != null) {
                    codec.stop();
                    codec.release();
                }
                if (extractor != null) {
                    extractor.release();
                }

                isEndOfPlayer = true;
                isEndOfRecord = true;

                releaseAudioPlayer();
                Log.i(TAG, "run: 线程结束");
            }
        }

        private int selectAudioTrack(MediaExtractor extractor) {
            for (int i = 0; i < extractor.getTrackCount(); i++) {
                MediaFormat format = extractor.getTrackFormat(i);
                String mimeType = format.getString(MediaFormat.KEY_MIME);

                if (mimeType.startsWith("audio/")) {
                    // 找到音频轨道
                    return i;
                }
            }
            return -1;
        }
    }