CODEWITHSUNDEEP
javavideoappletvideo-encoding
Marcello Bastea-Forte
Marcello Bastea-Forte

Reputation: 1167

What library can I use to encode video in a Java Applet?

I would like to record the user's interaction in my Java Applet as a video to send (potentially stream) to my server with the intention of uploading to Youtube (or similar). A high frame-rate is not required (a couple frames per second is sufficient).

Minimizing the bandwidth used is preferred, so sending jpeg snapshots to the server and encoding server-side is my last resort.

Are there any lightweight Java video encoding libraries available that don't require native code?

Upvotes: 0

Views: 2602

Answers (4)

Stanislav Vitvitskyy
Stanislav Vitvitskyy

Reputation: 2377

You can encode your images into H.264/MP4 this way it would be immediately good for web streaming. To upload it in parallel to recording you can break up your sequence into small chunks, let's say 25-100 images each and upload each chunk as a separate movie.

You can do it in pure Java without any native code, just use JCodec ( http://jcodec.org ). Here's a handy class that you can use: 

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
        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);
    }
}

Upvotes: 1

Art Clarke
Art Clarke

Reputation: 2505

Xuggler can be used to encode pretty much any format from Java, but it requires a native component to be installed with it. There isn't an applet version available in the easy to use download, but some users have built custom versions of FFmpeg and Xuggler that they have used in downloadable applications. Try asking on the xuggler-users user group to see if others will help.

Upvotes: 1

George Profenza
George Profenza

Reputation: 51867

I'm new to java so don't take this to seriously :)

I guess a good start with video encoding in java is Java Media Framework. I haven't tried it, so I don't know what's they're support on flv encoding.

Since Flash Media Server is commercial, couldn't you use Red5 ? You would have a swf, not an applet, but you will get a broader percentage of viewers since Flash Player is pretty wide spreaded.

And Alex has a good point, since you need to upload the video to youtube, why not use they're API ?

hth

Upvotes: 1

Alex Martelli
Alex Martelli

Reputation: 882281

Why do you need to send the images or video form directly? Sounds like a big bandwidth expense. Just serialize and send the stream of UI events with timestamps, and reconstruct what the user should be seeing on your server later (some visual details may depend on the user's machine/setup, but your applet ain't gonna be able to get to them decently anyway).

Upvotes: 0

Related Questions