Xuggler的Java視頻解碼錯誤

Question

我通過遵循指導 如何解碼和播放視頻的教程中的代碼，學習Xuggler（一個庫支持Java的視頻流）。

我以為這段代碼是可靠的，但是當我想播放在窗口上讀取的視頻時，出現錯誤告訴我

Exception in thread "main" java.lang.RuntimeException: got error decoding video in: C:/Users/swnmlab/1.mp4

執行此行時會發生此錯誤

int bytesDecoded = videoCoder.decodeVideo(picture, packet,offset);

我使用調試器進入並發現xuggle-xuggler.jar沒有源附件，以前有人遇到過此問題嗎？

import java.awt.image.BufferedImage;

import com.xuggle.xuggler.ICodec.Type;
import com.xuggle.xuggler.IContainer;
import com.xuggle.xuggler.IPacket;
import com.xuggle.xuggler.IPixelFormat;
import com.xuggle.xuggler.IStream;
import com.xuggle.xuggler.IStreamCoder;
import com.xuggle.xuggler.IVideoPicture;
import com.xuggle.xuggler.IVideoResampler;
import com.xuggle.xuggler.Utils;
import com.xuggle.xuggler.demos.VideoImage;

public class DecodeAndPlayVideo {
    public static void main(String[] args) {
        String filename = "C:/Users/swnmlab/1.mp4";

        // Create a Xuggler container object
        IContainer container = IContainer.make();

        // Open up the container
        if (container.open(filename, IContainer.Type.READ, null) < 0)
            throw new IllegalArgumentException("could not open file: "
                    + filename);

        // query how many streams the call to open found
        int numStreams = container.getNumStreams();

        // and iterate through the streams to find the first video stream
        int videoStreamId = -1;
        IStreamCoder videoCoder = null;
        for (int i = 0; i < numStreams; i++) {
            // Find the stream object
            IStream stream = container.getStream(i);
            // Get the pre-configured decoder that can decode this stream;
            IStreamCoder coder = stream.getStreamCoder();

            if (coder.getCodecType() == Type.CODEC_TYPE_VIDEO) {
                videoStreamId = i;
                videoCoder = coder;
                break;
            }
        }
        if (videoStreamId == -1)
            throw new RuntimeException(
                    "could not find video stream in container: " + filename);

        if (videoCoder.acquire() < 0)
            throw new RuntimeException(
                    "could not open video decoder for container: " + filename);

        IVideoResampler resampler = null;
        if (videoCoder.getPixelType() != IPixelFormat.Type.BGR24) {
            // if this stream is not in BGR24, we're going to need to
            // convert it. The VideoResampler does that for us.
            resampler = IVideoResampler.make(videoCoder.getWidth(),
                    videoCoder.getHeight(), IPixelFormat.Type.BGR24,
                    videoCoder.getWidth(), videoCoder.getHeight(),
                    videoCoder.getPixelType());
            if (resampler == null)
                throw new RuntimeException("could not create color space "
                        + "resampler for: " + filename);
        }

        /*
         * And once we have that, we draw a window on screen
         */
        openJavaWindow();

        IPacket packet = IPacket.make();
        while (container.readNextPacket(packet) >= 0) {
            /*
             * Now we have a packet, let's see if it belongs to our video stream
             */
            if (packet.getStreamIndex() == videoStreamId) {
                IVideoPicture picture = IVideoPicture.make(
                        videoCoder.getPixelType(), videoCoder.getWidth(),
                        videoCoder.getHeight());

                int offset = 0;
                while (offset < packet.getSize()) {
                    /*
                     * Now, we decode the video, checking for any errors.
                     */
                    int bytesDecoded = videoCoder.decodeVideo(picture, packet,
                            offset);
                    if (bytesDecoded < 0)
                        throw new RuntimeException(
                                "got error decoding video in: " + filename);
                    offset += bytesDecoded;

                    /*
                     * Some decoders will consume data in a packet, but will not
                     * be able to construct a full video picture yet. Therefore
                     * you should always check if you got a complete picture
                     * from the decoder
                     */
                    if (picture.isComplete()) {
                        IVideoPicture newPic = picture;
                        /*
                         * If the resampler is not null, that means we didn't
                         * get the video in BGR24 format and need to convert it
                         * into BGR24 format.
                         */
                        if (resampler != null) {
                            // we must resample
                            newPic = IVideoPicture.make(
                                    resampler.getOutputPixelFormat(),
                                    picture.getWidth(), picture.getHeight());
                            if (resampler.resample(newPic, picture) < 0)
                                throw new RuntimeException(
                                        "could not resample video from: "
                                                + filename);
                        }
                        if (newPic.getPixelType() != IPixelFormat.Type.BGR24)
                            throw new RuntimeException("could not decode video"
                                    + " as BGR 24 bit data in: " + filename);


                        @SuppressWarnings("deprecation")
                        BufferedImage javaImage = Utils.videoPictureToImage(newPic);

                        // and display it on the Java Swing window
                        updateJavaWindow(javaImage);    
                    }

                }
            } else {
                /*
                 * This packet isn't part of our video stream, so we just silently drop it.
                 */
                do {
                } while (false);
            }
        }

        closeJavaWindow();

    }

    private static VideoImage mScreen = null;
    private static void updateJavaWindow(BufferedImage javaImage) {
        mScreen.setImage(javaImage);
    }

    private static void openJavaWindow() {
        mScreen = new VideoImage();
    }

    private static void closeJavaWindow() {
        System.exit(0);
    }
}

PS如果要嘗試使用此庫，可以在此處找到安裝文件，然后按照本頁上的步驟完成在Windows上的安裝。

---

我發現錯誤發生是因為我更改了原始代碼

        if (videoCoder.open() < 0)
            throw new RuntimeException(
                    "could not open video decoder for container: " + filename);

至

        if (videoCoder.acquire() < 0)
            throw new RuntimeException(
                    "could not open video decoder for container: " + filename);

由於open（）方法會導致棄用警告，因此我使用自動完成功能來查找類似於open（）的方法，然后將其更改為Acquisition（）。 我認為還可以，因為沒有拋出“無法為容器打開視頻解碼器：”異常。因此，請遵循示例代碼。

Answer 1

不建議使用open（）方法，而應改用open（null，null）

if (videoCoder.open(null,null) < 0)
throw new RuntimeException(
        "could not open video decoder for container: "
                + filename);

Answer 2

我檢查了您的代碼，發現您獲得了videoCoder ，但是在播放之前沒有open它。 也許這就是為什么您無法對其進行解碼的原因。 那你可以試試看嗎？

if (videoCoder.open() < 0)
    throw new RuntimeException(
            "could not open video decoder for container: "
                    + filename);
IVideoResampler resampler = null;

Answer 3

我通過以下代碼更改執行了相同的代碼。 這些更改是必需的，因為不推薦使用以下API。

IMetaData params = IMetaData.make();
IContainerParameters params = IContainerParameters.make();

如圖所示，我使用videoCoder設置了timeBase，Height和Width。

  if (coder.getCodecType() == ICodec.Type.CODEC_TYPE_VIDEO)
  {
    videoStreamId = i;
    videoCoder = coder;

    // The timebase here is used as the camera frame rate    
    videoCoder.setTimeBase(IRational.make(30,1));

    // we need to tell the driver what video with and height to use
    videoCoder.setWidth(320);
    videoCoder.setHeight(240);

    break;
  }

但是，我面臨一個不同的問題，即攝像頭顯示占據整個屏幕，而不是指定的寬度和高度。

設置高度和寬度的代碼更改不正確嗎？ 我們應該如何控制大小？