Encoding yuv frames to video file in java

user_3071996 0
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I am trying to encode a video in java. I have access to the separate frames as I420 yuv frames (these come from a different part of the program that I cannot change). I basically have 3 bytebuffers for the different planes of a frame (+ dimensions). As far as I understand, my format has 1 byte for the y-plane, and half a byte for u and v each, per pixel.

What is the best way to encode these into an mp4 video file? I have tried with the xuggler API, but I can't seem to find a way to use the yuv frames directly. Right now, I would convert them to a BufferedImage (TYPE_3BYTE_BGR) first before I can use them with the xuggler api to encode them to a video.

But this creates a huge overhead (I have to convert the yuv data to rgb for each pixel) and is unnecessary, as xuggler encodes them to yuv frames again to store them in a video file? (Not sure about this.)

So is there any easier way to encode raw yuv-frames to a video file directly in java?

Thanks for any pointers.

xuggler yuv video-encoding video java
2 Answers

I can´t remember the source of this code, probably it was from a question here in SO, but comes in handy here as it´s a version of the above using integer maths, I needed it for an Android project!

    //Method from Ketai project! Not mine! See below...
void decodeYUV420SP(int[] rgb, byte[] yuv420sp, int width, int height) {

    final int frameSize = width * height;

    for (int j = 0, yp = 0; j < height; j++) {

        int uvp = frameSize + (j >> 1) * width, u = 0, v = 0;

        for (int i = 0; i < width; i++, yp++) {

            int y = (0xff & ((int) yuv420sp[yp])) - 16;
            if (y < 0)
                y = 0;
            if ((i & 1) == 0) {
                v = (0xff & yuv420sp[uvp++]) - 128;
                u = (0xff & yuv420sp[uvp++]) - 128;
            }

            int y1192 = 1192 * y;
            int r = (y1192 + 1634 * v);
            int g = (y1192 - 833 * v - 400 * u);
            int b = (y1192 + 2066 * u);

            if (r < 0) r = 0;
            else if (r > 262143)
                r = 262143;
            if (g < 0) g = 0;
            else if (g > 262143)
                g = 262143;
            if (b < 0) b = 0;
            else if (b > 262143)
                b = 262143;

            rgb[yp] = 0xff000000 | ((r << 6) & 0xff0000) | ((g >> 2) & 0xff00) | ((b >> 10) & 0xff);
        }
    }
}
user_11083970
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