android中 MediaCodec 压缩视频使用示例,带调用的main方法，压缩一个测试的视频

好的，以下是一个简单的使用 MediaCodec 压缩视频的示例代码，包括调用的 main 方法和压缩测试视频：

import android.media.MediaCodec;
import android.media.MediaCodecInfo;
import android.media.MediaFormat;
import android.media.MediaMuxer;
import android.os.Environment;
import android.util.Log;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.nio.ByteBuffer;

public class VideoCompressor {

    private static final String TAG = "VideoCompressor";
    private static final String TEST_VIDEO_PATH = Environment.getExternalStorageDirectory() + "/test.mp4";
    private static final String COMPRESSED_VIDEO_PATH = Environment.getExternalStorageDirectory() + "/compressed.mp4";
    private static final String MIME_TYPE = "video/avc";
    private static final int FRAME_RATE = 30;
    private static final int I_FRAME_INTERVAL = 1;
    private static final int BIT_RATE = 500000;

    public static void main(String[] args) {
        try {
            VideoCompressor compressor = new VideoCompressor();
            compressor.compressVideo(TEST_VIDEO_PATH, COMPRESSED_VIDEO_PATH);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public void compressVideo(String inputFilePath, String outputFilePath) throws IOException {
        Log.i(TAG, "compressVideo: inputFilePath=" + inputFilePath + ", outputFilePath=" + outputFilePath);

        // Read input video file
        FileInputStream inputFile = new FileInputStream(new File(inputFilePath));
        byte[] inputData = new byte[inputFile.available()];
        inputFile.read(inputData);
        inputFile.close();

        // Set up MediaCodec encoder
        MediaCodec encoder = MediaCodec.createEncoderByType(MIME_TYPE);
        MediaFormat format = MediaFormat.createVideoFormat(MIME_TYPE, 1920, 1080);
        format.setInteger(MediaFormat.KEY_COLOR_FORMAT, MediaCodecInfo.CodecCapabilities.COLOR_FormatSurface);
        format.setInteger(MediaFormat.KEY_BIT_RATE, BIT_RATE);
        format.setInteger(MediaFormat.KEY_FRAME_RATE, FRAME_RATE);
        format.setInteger(MediaFormat.KEY_I_FRAME_INTERVAL, I_FRAME_INTERVAL);
        encoder.configure(format, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE);
        encoder.start();

        // Set up MediaMuxer
        MediaMuxer muxer = new MediaMuxer(outputFilePath, MediaMuxer.OutputFormat.MUXER_OUTPUT_MPEG_4);

        // Start encoding
        ByteBuffer[] inputBuffers = encoder.getInputBuffers();
        ByteBuffer[] outputBuffers = encoder.getOutputBuffers();
        MediaCodec.BufferInfo bufferInfo = new MediaCodec.BufferInfo();
        boolean isInputDone = false;
        boolean isOutputDone = false;
        int frameCount = 0;
        while (!isOutputDone) {
            if (!isInputDone) {
                int inputBufferIndex = encoder.dequeueInputBuffer(-1);
                if (inputBufferIndex >= 0) {
                    ByteBuffer inputBuffer = inputBuffers[inputBufferIndex];
                    inputBuffer.clear();
                    inputBuffer.put(inputData);
                    encoder.queueInputBuffer(inputBufferIndex, 0, inputData.length, frameCount * 1000000 / FRAME_RATE, 0);
                    frameCount++;
                } else {
                    isInputDone = true;
                }
            }

            while (!isOutputDone) {
                int outputBufferIndex = encoder.dequeueOutputBuffer(bufferInfo, 0);
                if (outputBufferIndex == MediaCodec.INFO_TRY_AGAIN_LATER) {
                    break;
                } else if (outputBufferIndex == MediaCodec.INFO_OUTPUT_FORMAT_CHANGED) {
                    MediaFormat newFormat = encoder.getOutputFormat();
                    Log.i(TAG, "compressVideo: output format changed: " + newFormat);
                    muxer.addTrack(newFormat);
                } else if (outputBufferIndex < 0) {
                    Log.w(TAG, "compressVideo: unexpected result from encoder.dequeueOutputBuffer: " + outputBufferIndex);
                } else {
                    ByteBuffer outputBuffer = outputBuffers[outputBufferIndex];
                    if ((bufferInfo.flags & MediaCodec.BUFFER_FLAG_CODEC_CONFIG) != 0) {
                        bufferInfo.size = 0;
                    }

                    if (bufferInfo.size != 0) {
                        outputBuffer.position(bufferInfo.offset);
                        outputBuffer.limit(bufferInfo.offset + bufferInfo.size);
                        muxer.writeSampleData(0, outputBuffer, bufferInfo);
                    }

                    encoder.releaseOutputBuffer(outputBufferIndex, false);

                    if ((bufferInfo.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0) {
                        isOutputDone = true;
                    }

                    break;
                }
            }
        }

        // Release resources
        muxer.stop();
        muxer.release();
        encoder.stop();
        encoder.release();

        Log.i(TAG, "compressVideo: done");
    }
}

这个示例代码会读取指定路径下的 `test.mp4` 视频文件，并使用 MediaCodec 将其压缩为指定路径下的 `compressed.mp4` 文件。压缩的视频编码格式为 H.264，分辨率为 1920x1080，帧率为 30 帧/秒，关键帧间隔为 1 秒，比特率为 500000 bps。这些参数可以根据实际需要进行修改。