glide加载mp4 源码堆栈调用核心代码分析

load 数据走的httpurlfetcher 的loaddata 从MultiLoader 调用而来

load到inputstream流后的处理核心

图片是glide 首先创建解释器的时候加了videodecoder 然后这里会从流中加载对应帧的图片保存在手机cache目录中将这个file 作为bitmap传递然后加载

  private static final class ByteBufferFetcher implements DataFetcher<ByteBuffer> {

    private final File file;

    @Synthetic
    @SuppressWarnings("WeakerAccess")
    ByteBufferFetcher(File file) {
      this.file = file;
    }

几个核心的类 VideoDecoder

public interface VideoDecoder {
  /** Settings passed to the decoder by WebRTC. */
  public class Settings {
    public final int numberOfCores;
    public final int width;
    public final int height;

    @CalledByNative("Settings")
    public Settings(int numberOfCores, int width, int height) {
      this.numberOfCores = numberOfCores;
      this.width = width;
      this.height = height;
    }
  }

  /** Additional info for decoding. */
  public class DecodeInfo {
    public final boolean isMissingFrames;
    public final long renderTimeMs;

    public DecodeInfo(boolean isMissingFrames, long renderTimeMs) {
      this.isMissingFrames = isMissingFrames;
      this.renderTimeMs = renderTimeMs;
    }
  }

  public interface Callback {
    /**
     * Call to return a decoded frame. Can be called on any thread.
     *
     * @param frame Decoded frame
     * @param decodeTimeMs Time it took to decode the frame in milliseconds or null if not available
     * @param qp QP value of the decoded frame or null if not available
     */
    void onDecodedFrame(VideoFrame frame, Integer decodeTimeMs, Integer qp);
  }

以及VideoBitmapDecoder

@Deprecated
public class VideoBitmapDecoder extends VideoDecoder<ParcelFileDescriptor> {

  @SuppressWarnings("unused")
  public VideoBitmapDecoder(Context context) {
    this(Glide.get(context).getBitmapPool());
  }

  // Public API
  @SuppressWarnings("WeakerAccess")
  public VideoBitmapDecoder(BitmapPool bitmapPool) {
    super(bitmapPool, new ParcelFileDescriptorInitializer());
  }
}

以上就是 video加载核心部分的分析在VideoDecoder：：decode() 以及加上断点就可以很清楚的分析出load到图片以后的transform过程