Android平台RTMP|RTSP播放器如何回调YUV或RGB数据？

技术选型

我们知道，Android平台一般RTMP|RTSP播放器通常不直接提供回调YUV或RGB数据的功能。如果播放端有视觉分析或类似的需求，需要播放端，能支持YUV或ARG的数据回调，一般来说，可参考的方法如下：

1. 使用FFmpeg和JNI

FFmpeg是一个强大的多媒体处理库，它支持解码视频并提取帧数据。你可以通过JNI在Android的Java层调用C/C++层的FFmpeg库来解码RTSP流，并获取YUV或RGB数据。

步骤：

将FFmpeg库集成到你的Android项目中。
使用FFmpeg的API来设置RTSP流的解码器。
解码视频帧，并将YUV或RGB数据从解码器传输到Java层。

2. 使用OpenGL ES

如果你使用的是OpenGL ES进行视频渲染，你可以在着色器（Shader）中处理视频帧的YUV数据，并将其转换为RGB格式（如果需要）。然而，这种方法并不会直接回调YUV或RGB数据到Java层，而是允许你在GPU级别上操作这些数据。

3. 使用MediaCodec和ImageReader

从Android 5.0（API 级别 21）开始，MediaCodec支持与ImageReader一起使用，以捕获解码后的视频帧作为Image对象。这些Image对象可以直接访问YUV或RGB数据（取决于配置）。

步骤：

配置MediaCodec以使用ImageReader作为输出。
解码RTSP流并捕获解码后的帧。
从ImageReader的Image对象中读取YUV或RGB数据。

4. 使用第三方RTMP|RTSP播放器直接回调数据

以大牛直播SDK的RTMP|RTSP播放模块为例，我们是可以直接设置YUV或RGB数据回调，并提供相关调用示例：

java 复制代码

btnStartStopPlayback.setOnClickListener(new Button.OnClickListener() {

	// @Override
	public void onClick(View v) {

		if (isPlaying) {
			Log.i(TAG, "Stop playback stream++");

			int iRet = libPlayer.SmartPlayerStopPlay(playerHandle);

			if (iRet != 0) {
				Log.e(TAG, "Call SmartPlayerStopPlay failed..");
				return;
			}

			btnHardwareDecoder.setEnabled(true);
			btnLowLatency.setEnabled(true);

			if (!isRecording) {
				btnPopInputUrl.setEnabled(true);
				btnPopInputKey.setEnabled(true);
				btnSetPlayBuffer.setEnabled(true);
				btnFastStartup.setEnabled(true);

				btnRecoderMgr.setEnabled(true);
				libPlayer.SmartPlayerClose(playerHandle);
				playerHandle = 0;
			}

			isPlaying = false;
			btnStartStopPlayback.setText("开始播放 ");

			if (is_enable_hardware_render_mode && sSurfaceView != null) {
				sSurfaceView.setVisibility(View.GONE);
				sSurfaceView.setVisibility(View.VISIBLE);
			}

			Log.i(TAG, "Stop playback stream--");
		} else {
			Log.i(TAG, "Start playback stream++");

			if (!isRecording) {
				InitAndSetConfig();
			}

			// 如果第二个参数设置为null，则播放纯音频
			libPlayer.SmartPlayerSetSurface(playerHandle, sSurfaceView);

			libPlayer.SmartPlayerSetRenderScaleMode(playerHandle, 1);

			//int render_format = 1;
			//libPlayer.SmartPlayerSetSurfaceRenderFormat(playerHandle, render_format);

			//int is_enable_anti_alias = 1;
			//libPlayer.SmartPlayerSetSurfaceAntiAlias(playerHandle, is_enable_anti_alias);

			if (isHardwareDecoder && is_enable_hardware_render_mode) {
				libPlayer.SmartPlayerSetHWRenderMode(playerHandle, 1);
			}

			// External Render test
			//libPlayer.SmartPlayerSetExternalRender(playerHandle, new RGBAExternalRender(imageSavePath));
			libPlayer.SmartPlayerSetExternalRender(playerHandle, new I420ExternalRender(imageSavePath));

			libPlayer.SmartPlayerSetUserDataCallback(playerHandle, new UserDataCallback());
			//libPlayer.SmartPlayerSetSEIDataCallback(playerHandle, new SEIDataCallback());

			libPlayer.SmartPlayerSetAudioOutputType(playerHandle, 1);

			if (isMute) {
				libPlayer.SmartPlayerSetMute(playerHandle, isMute ? 1
						: 0);
			}

			if (isHardwareDecoder) {
				int isSupportHevcHwDecoder = libPlayer.SetSmartPlayerVideoHevcHWDecoder(playerHandle, 1);

				int isSupportH264HwDecoder = libPlayer
						.SetSmartPlayerVideoHWDecoder(playerHandle, 1);

				Log.i(TAG, "isSupportH264HwDecoder: " + isSupportH264HwDecoder + ", isSupportHevcHwDecoder: " + isSupportHevcHwDecoder);
			}

			libPlayer.SmartPlayerSetLowLatencyMode(playerHandle, isLowLatency ? 1
					: 0);

			libPlayer.SmartPlayerSetFlipVertical(playerHandle, is_flip_vertical ? 1 : 0);

			libPlayer.SmartPlayerSetFlipHorizontal(playerHandle, is_flip_horizontal ? 1 : 0);

			libPlayer.SmartPlayerSetRotation(playerHandle, rotate_degrees);

			libPlayer.SmartPlayerSetAudioVolume(playerHandle, curAudioVolume);

			int iPlaybackRet = libPlayer
					.SmartPlayerStartPlay(playerHandle);

			if (iPlaybackRet != 0) {
				Log.e(TAG, "Call SmartPlayerStartPlay failed..");
				return;
			}

			btnStartStopPlayback.setText("停止播放 ");

			btnPopInputUrl.setEnabled(false);
			btnPopInputKey.setEnabled(false);
			btnHardwareDecoder.setEnabled(false);
			btnSetPlayBuffer.setEnabled(false);
			btnLowLatency.setEnabled(false);
			btnFastStartup.setEnabled(false);
			btnRecoderMgr.setEnabled(false);

			isPlaying = true;
			Log.i(TAG, "Start playback stream--");
		}
	}
});

对应的设置如下：

java 复制代码

// External Render test
libPlayer.SmartPlayerSetExternalRender(playerHandle, new RGBAExternalRender(imageSavePath));
libPlayer.SmartPlayerSetExternalRender(playerHandle, new I420ExternalRender(imageSavePath));

如果是RGBA数据，处理如下：

java 复制代码

/*
 * RGBA数据回调处理
 * Author: daniusdk.com
 * WeChat: xinsheng120
 */   
private static class RGBAExternalRender implements NTExternalRender {
        // public static final int NT_FRAME_FORMAT_RGBA = 1;
        // public static final int NT_FRAME_FORMAT_ABGR = 2;
        // public static final int NT_FRAME_FORMAT_I420 = 3;

        private final String image_path_;
        private long last_save_image_time_ms_;

        private int width_;
        private int height_;
        private int row_bytes_;

        private ByteBuffer rgba_buffer_;

        public RGBAExternalRender(String image_path) {
            this.image_path_ = image_path;
        }

        @Override
        public int getNTFrameFormat() {
            Log.i(TAG, "RGBAExternalRender::getNTFrameFormat return " + NT_FRAME_FORMAT_RGBA);
            return NT_FRAME_FORMAT_RGBA;
        }

        @Override
        public void onNTFrameSizeChanged(int width, int height) {
            width_ = width;
            height_ = height;

            row_bytes_ = width_ * 4;
            rgba_buffer_ = ByteBuffer.allocateDirect(row_bytes_ * height_);

            Log.i(TAG, "RGBAExternalRender::onNTFrameSizeChanged width_:" + width_ + " height_:" + height_);
        }

        @Override
        public ByteBuffer getNTPlaneByteBuffer(int index) {
            if (index == 0)
                return rgba_buffer_;

            Log.e(TAG, "RGBAExternalRender::getNTPlaneByteBuffer index error:" + index);
            return null;
        }

        @Override
        public int getNTPlanePerRowBytes(int index) {
            if (index == 0)
                return row_bytes_;

            Log.e(TAG, "RGBAExternalRender::getNTPlanePerRowBytes index error:" + index);
            return 0;
        }

        public void onNTRenderFrame(int width, int height, long timestamp) {
            if (rgba_buffer_ == null)
                return;

            rgba_buffer_.rewind();

            // copy buffer

            // test
            // byte[] test_buffer = new byte[16];
            // rgba_buffer_.get(test_buffer);

           Log.i(TAG, "RGBAExternalRender:onNTRenderFrame " + width + "*" + height + ", t:" + timestamp);

            // Log.i(TAG, "RGBAExternalRender:onNTRenderFrame rgba:" +
            // bytesToHexString(test_buffer));
        }
    }

如果是I420数据：

java 复制代码

/*
 *YUV数据回调处理
 * Author: daniusdk.com
 * WeChat: xinsheng120
 */   
private static class I420ExternalRender implements NTExternalRender {
        // public static final int NT_FRAME_FORMAT_RGBA = 1;
        // public static final int NT_FRAME_FORMAT_ABGR = 2;
        // public static final int NT_FRAME_FORMAT_I420 = 3;

        private final String image_path_;
        private long last_save_image_time_ms_;

        private int width_;
        private int height_;

        private int y_row_bytes_;
        private int u_row_bytes_;
        private int v_row_bytes_;

        private ByteBuffer y_buffer_;
        private ByteBuffer u_buffer_;
        private ByteBuffer v_buffer_;

        public I420ExternalRender(String image_path) {
            this.image_path_ = image_path;
        }

        @Override
        public int getNTFrameFormat() {
            Log.i(TAG, "I420ExternalRender::getNTFrameFormat return " + NT_FRAME_FORMAT_I420);
            return NT_FRAME_FORMAT_I420;
        }

        @Override
        public void onNTFrameSizeChanged(int width, int height) {
            width_ = width;
            height_ = height;

            y_row_bytes_ = width;
            u_row_bytes_ = (width+1)/2;
            v_row_bytes_ = (width+1)/2;

            y_buffer_ = ByteBuffer.allocateDirect(y_row_bytes_*height_);
            u_buffer_ = ByteBuffer.allocateDirect(u_row_bytes_*((height_ + 1) / 2));
            v_buffer_ = ByteBuffer.allocateDirect(v_row_bytes_*((height_ + 1) / 2));

            Log.i(TAG, "I420ExternalRender::onNTFrameSizeChanged width_="
                    + width_ + " height_=" + height_ + " y_row_bytes_="
                    + y_row_bytes_ + " u_row_bytes_=" + u_row_bytes_
                    + " v_row_bytes_=" + v_row_bytes_);
        }

        @Override
        public ByteBuffer getNTPlaneByteBuffer(int index) {
            switch (index) {
                case 0:
                    return y_buffer_;
                case 1:
                    return u_buffer_;
                case 2:
                    return v_buffer_;
                default:
                    Log.e(TAG, "I420ExternalRender::getNTPlaneByteBuffer index error:" + index);
                    return null;
            }
        }

        @Override
        public int getNTPlanePerRowBytes(int index) {
            switch (index) {
                case 0:
                    return y_row_bytes_;
                case 1:
                    return u_row_bytes_;
                case 2:
                    return v_row_bytes_;
                default:
                    Log.e(TAG, "I420ExternalRender::getNTPlanePerRowBytes index error:" + index);
                    return 0;
            }
        }

        public void onNTRenderFrame(int width, int height, long timestamp) {
            if (null == y_buffer_ || null == u_buffer_ || null == v_buffer_)
                return;

            y_buffer_.rewind();
            u_buffer_.rewind();
            v_buffer_.rewind();

            Log.i(TAG, "I420ExternalRender::onNTRenderFrame " + width + "*" + height + ", t:" + timestamp);

        }
    }

总结

无论使用哪种方法，处理视频帧数据都可能是计算密集型的，特别是在高清视频或高帧率视频的情况下。确保你的应用能够处理这些性能要求，并考虑在后台线程中执行解码和数据处理操作。确保回调数据，尽可能小的占用资源。以上抛砖引玉，感兴趣的开发者，可以单独跟我沟通讨论。