H264Decoder.java

/*
This file is part of jpcsp.

Jpcsp is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

Jpcsp is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with Jpcsp.  If not, see <http://www.gnu.org/licenses/>.
 */
package jpcsp.media.codec.h264;

import org.apache.log4j.Logger;

import com.twilight.h264.decoder.AVFrame;
import com.twilight.h264.decoder.AVPacket;
import com.twilight.h264.decoder.AVRational;
import com.twilight.h264.decoder.MpegEncContext;

import jpcsp.media.codec.IVideoCodec;

public class H264Decoder implements IVideoCodec {
	private static Logger log = Logger.getLogger("h264");
	private MpegEncContext context;
	private AVFrame picture;
	private AVPacket packet;
	private final int gotPicture[] = new int[1];
	private AVRational aspectRatio;

	@Override
	public int init(int extraData[]) {
		context = MpegEncContext.avcodec_alloc_context();

		picture = AVFrame.avcodec_alloc_frame();

		packet = new AVPacket();
		packet.av_init_packet();

		if (extraData != null) {
			context.extradata_size = extraData.length;
			// Add 4 additional values to avoid exceptions while parsing
			int[] extraDataPlus4 = new int[context.extradata_size + 4];
			System.arraycopy(extraData, 0, extraDataPlus4, 0, context.extradata_size);
			context.extradata = extraDataPlus4;
		}

		int result = context.avcodec_open(new com.twilight.h264.decoder.H264Decoder());
		if (result < 0) {
			return result;
		}

		gotPicture[0] = 0;

		return 0;
	}

	@Override
	public int decode(int input[], int inputOffset, int inputLength) {
		packet.data_base = input;
		packet.data_offset = inputOffset;
		packet.size = inputLength;

		int consumedLength;
		try {
			consumedLength = context.avcodec_decode_video2(picture, gotPicture, packet);
		} catch (ArrayIndexOutOfBoundsException e) {
			log.error("H264Decoder.decode", e);
			return -1;
		}

		if (consumedLength < 0) {
			log.error(String.format("H264 decode error 0x%08X", consumedLength));
			gotPicture[0] = 0;
			return consumedLength;
		}

		if (hasImage()) {
			context.priv_data.displayPicture.copyTo(picture);
			aspectRatio = context.sample_aspect_ratio;
		}

		return consumedLength;
	}

	@Override
	public boolean hasImage() {
		return gotPicture[0] != 0;
	}

	@Override
	public int getImageWidth() {
		return context.width;
	}

	@Override
	public int getImageHeight() {
		return context.height;
	}

	@Override
	public boolean isKeyFrame() {
		return picture.key_frame != 0;
	}

	@Override
	public void getAspectRatio(int[] numDen) {
		numDen[0] = aspectRatio.num;
		numDen[1] = aspectRatio.den;
	}

	@Override
	public int getImage(int[] luma, int[] cb, int[] cr) {
		int width = getImageWidth();
		int height = getImageHeight();
		int width2 = width >> 1;
		int height2 = height >> 1;

		// Copy luma component: width * height values
		for (int y = 0; y < height; y++) {
			System.arraycopy(picture.data_base[0], y * picture.linesize[0] + picture.data_offset[0], luma, y * width , width );
		}

		// Copy Cb and Cr components: width2 * height2 values each
		for (int y = 0; y < height2; y++) {
			System.arraycopy(picture.data_base[1], y * picture.linesize[1] + picture.data_offset[1], cb  , y * width2, width2);
			System.arraycopy(picture.data_base[2], y * picture.linesize[2] + picture.data_offset[2], cr  , y * width2, width2);
		}

		return 0;
	}
}