java - jcodec - 有人看过这个库的文档吗？

Question

我正在尝试使用 jcodec 将缓冲图像编码为 h264 电影。只有我无法在任何地方找到示例代码。

过去有人用过这个库吗？我没有看到任何文档，甚至库附带的 javadoc 也没有包含使用信息。如果您看过示例，或者可以提供见解，请告诉我。

http://jcodec.org/

提前致谢

Answer 1

JCodec 不支持 H.264 编码。但是，您可以将 JNA 与 x264 库或 ffmpeg 一起使用。如果您选择这条路线，此线程可能会帮助您开始：如何使用 x264 C API 将一系列图像编码为 H264？.

[更新]从 0.1.0 版开始，JCodec 支持 H.264 编码，这是一个简单的类，可用于将图像序列转换为 MP4 容器中的 H.264 视频：

public class SequenceEncoder {
    private SeekableByteChannel ch;
    private Picture toEncode;
    private RgbToYuv420 transform;
    private H264Encoder encoder;
    private ArrayList<ByteBuffer> spsList;
    private ArrayList<ByteBuffer> ppsList;
    private CompressedTrack outTrack;
    private ByteBuffer _out;
    private int frameNo;
    private MP4Muxer muxer;

    public SequenceEncoder(File out) throws IOException {
        this.ch = NIOUtils.writableFileChannel(out);

        // Transform to convert between RGB and YUV
        transform = new RgbToYuv420(0, 0);

        // Muxer that will store the encoded frames
        muxer = new MP4Muxer(ch, Brand.MP4);

        // Add video track to muxer
        outTrack = muxer.addTrackForCompressed(TrackType.VIDEO, 25);

        // Allocate a buffer big enough to hold output frames
        _out = ByteBuffer.allocate(1920 * 1080 * 6);

        // Create an instance of encoder
        encoder = new H264Encoder();

        // Encoder extra data ( SPS, PPS ) to be stored in a special place of
        // MP4
        spsList = new ArrayList<ByteBuffer>();
        ppsList = new ArrayList<ByteBuffer>();

    }

    public void encodeImage(BufferedImage bi) throws IOException {
        if (toEncode == null) {
            toEncode = Picture.create(bi.getWidth(), bi.getHeight(), ColorSpace.YUV420);
        }

        // Perform conversion
        for (int i = 0; i < 3; i++)
            Arrays.fill(toEncode.getData()[i], 0);
        transform.transform(AWTUtil.fromBufferedImage(bi), toEncode);

        // Encode image into H.264 frame, the result is stored in '_out' buffer
        _out.clear();
        ByteBuffer result = encoder.encodeFrame(_out, toEncode);

        // Based on the frame above form correct MP4 packet
        spsList.clear();
        ppsList.clear();
        H264Utils.encodeMOVPacket(result, spsList, ppsList);

        // Add packet to video track
        outTrack.addFrame(new MP4Packet(result, frameNo, 25, 1, frameNo, true, null, frameNo, 0));

        frameNo++;
    }

    public void finish() throws IOException {
        // Push saved SPS/PPS to a special storage in MP4
        outTrack.addSampleEntry(H264Utils.createMOVSampleEntry(spsList, ppsList));

        // Write MP4 header and finalize recording
        muxer.writeHeader();
        NIOUtils.closeQuietly(ch);
    }

    public static void main(String[] args) throws IOException {
        SequenceEncoder encoder = new SequenceEncoder(new File("video.mp4"));
        for (int i = 1; i < 100; i++) {
            BufferedImage bi = ImageIO.read(new File(String.format("folder/img%08d.png", i)));
            encoder.encodeImage(bi);
        }
        encoder.finish();
    }
}

[更新 1]使用此代码将交错的 YUV 4:2:0 字节数组转换为 JCodec 图片：

byte[] input = ...
Picture output = Picture.create(width, height, ColorSpace.YUV420);
int[] d0 = output.getData()[0], d1 = output.getData()[1], d2 = output.getData()[2];

for(int i = 0, j0 = 0, j1 = 0, j2 = 0; i < input.length; i += 6, j0 += 4, ++j1 , ++j2) {
    d0[j0    ] = input[i    ] & 0xff;
    d0[j0 + 1] = input[i + 1] & 0xff;
    d0[j0 + 2] = input[i + 2] & 0xff;
    d0[j0 + 3] = input[i + 3] & 0xff;

    d1[j1    ] = input[i + 4] & 0xff;
    d2[j2    ] = input[i + 5] & 0xff;
}