背景
我们在做Android平台GB28181设备接入模块的时候,有开发者提到这样的诉求:他们的智能头盔、执法记录仪等设备,采集到的图像,是旋转了90、180甚至270°的,设备本身无法针对图像做翻转或者旋转操作,问我们这种情况下需要如何处理?
实际上,这块,我们前几年在做RTMP推送和轻量级RTSP服务模块的时候,老早处理了这类问题。
鉴于Android平台video数据采集分camera和camera2(Android 5.0+)接口,我们单独说明:
camera接口示例
//Github: https://github.com/daniulive/SmarterStreaming//author: 89030985@qq.com@Overridepublic void onPreviewFrame(byte[] data, Camera camera) {frameCount++;if (frameCount % 3000 == 0) {Log.i("OnPre", "gc+");System.gc();Log.i("OnPre", "gc-");}if (data == null) {Parameters params = camera.getParameters();Size size = params.getPreviewSize();int bufferSize = (((size.width | 0x1f) + 1) * size.height * ImageFormat.getBitsPerPixel(params.getPreviewFormat())) / 8;camera.addCallbackBuffer(new byte[bufferSize]);} else {if (isRTSPPublisherRunning || isPushingRtmp || isRecording || isGB28181StreamRunning) {if (1 == video_opt_) {/* byte[] i420_data = new byte[videoWidth*videoHeight*3/2];libPublisher.SmartPublisherNV21ToI420Rotate(publisherHandle, data, videoWidth, videoWidth,i420_data, videoHeight, videoHeight/2, videoHeight/2,videoWidth, videoHeight, 90);libPublisher.SmartPublisherOnCaptureVideoI420DataV2(publisherHandle, i420_data, videoHeight, videoWidth,videoHeight, videoHeight/2, videoHeight/2);*/libPublisher.SmartPublisherOnCaptureVideoData(publisherHandle, data, data.length, currentCameraType, currentOrigentation);} else if (3 == video_opt_) {int w = videoWidth, h = videoHeight;int y_stride = videoWidth, uv_stride = videoWidth;int y_offset = 0, uv_offset = videoWidth * videoHeight;int is_vertical_flip = 0, is_horizontal_flip = 0;int rotation_degree = 0;// 镜像只用在前置摄像头场景下if (is_mirror && FRONT == currentCameraType) {// 竖屏, (垂直翻转->顺时旋转270度)等价于(顺时旋转旋转270度->水平翻转)if (PORTRAIT == currentOrigentation)is_vertical_flip = 1;elseis_horizontal_flip = 1;}if (PORTRAIT == currentOrigentation) {if (BACK == currentCameraType)rotation_degree = 90;elserotation_degree = 270;} else if (LANDSCAPE_LEFT_HOME_KEY == currentOrigentation) {rotation_degree = 180;}if (640 == w && 480 == h && PORTRAIT == currentOrigentation) {// 480 * 640 竖屏情况下裁剪到 368 * 640, 均匀裁剪掉视频的上下两部分h = 368;y_offset = 56 * y_stride;uv_offset += (56 >> 1) * uv_stride;}int scale_w = 0, scale_h = 0, scale_filter_mode = 0;// 缩放测试++/*if (w >= 1280 && h >= 720) {scale_w = align((int)(w * 0.8 + 0.5), 2);scale_h = align((int)(h * 0.8 + 0.5), 2);} else {scale_w = align((int)(w * 1.5 + 0.5), 2);scale_h = align((int)(h * 1.5 + 0.5), 2);}if(scale_w >0 && scale_h >0) {scale_filter_mode = 3;Log.i(TAG, "onPreviewFrame w:" + w + ", h:" + h + " s_w:" + scale_w + ", s_h:" + scale_h);}*/// 缩放测试---libPublisher.PostLayerImageNV21ByteArray(publisherHandle, 0, 0, 0,data, y_offset, y_stride, data, uv_offset, uv_stride, w, h,is_vertical_flip, is_horizontal_flip, scale_w, scale_h, scale_filter_mode, rotation_degree);// i420接口测试++/*byte[] i420_data = new byte[videoWidth*videoHeight*3/2];int u_stride = videoWidth >> 1;int v_stride = u_stride;libPublisher.SmartPublisherNV21ToI420Rotate(publisherHandle, data, y_stride, uv_stride, i420_data, y_stride, u_stride, v_stride,videoWidth, videoHeight, 0);y_offset = 0;int u_offset = y_offset + videoWidth * videoHeight;int v_offset = u_offset + videoWidth*videoHeight/4;libPublisher.PostLayerImageI420ByteArray(publisherHandle, 0, 0, 0,i420_data, y_offset, y_stride, i420_data, u_offset, u_stride, i420_data, v_offset, v_stride,w, h, is_vertical_flip, is_horizontal_flip, scale_w, scale_h, scale_filter_mode, rotation_degree);*/// i420接口测试--}}camera.addCallbackBuffer(data);}}
对应的接口设计如下:
/*** 投递层NV21图像** @param index: 层索引, 必须大于等于0** @param left: 层叠加的左上角坐标, 对于第0层的话传0** @param top: 层叠加的左上角坐标, 对于第0层的话传0** @param y_plane: y平面图像数据** @param y_offset: 图像偏移, 这个主要目的是用来做clip的,一般传0** @param y_row_stride: stride information** @param uv_plane: uv平面图像数据** @param uv_offset: 图像偏移, 这个主要目的是用来做clip的,一般传0** @param uv_row_stride: stride information** @param width: width, 必须大于1, 且必须是偶数** @param height: height, 必须大于1, 且必须是偶数** @param is_vertical_flip: 是否垂直翻转, 0不翻转, 1翻转** @param is_horizontal_flip:是否水平翻转, 0不翻转, 1翻转** @param scale_width: 缩放宽,必须是偶数, 0或负数不缩放** @param scale_height: 缩放高, 必须是偶数, 0或负数不缩放** @param scale_filter_mode: 缩放质量, 传0使用默认速度,可选等级范围是:[1,3],值越大缩放质量越好, 但速度越慢** @param rotation_degree: 顺时针旋转, 必须是0, 90, 180, 270, 注意:旋转是在缩放, 垂直/水品反转之后再做, 请留意顺序** @return {0} if successful*/public native int PostLayerImageNV21ByteArray(long handle, int index, int left, int top,byte[] y_plane, int y_offset, int y_row_stride,byte[] uv_plane, int uv_offset, int uv_row_stride,int width, int height, int is_vertical_flip, int is_horizontal_flip,int scale_width, int scale_height, int scale_filter_mode,int rotation_degree);
对应Camera2的接口示例
@Overridepublic void onCameraImageData(Image image) {Rect crop_rect = image.getCropRect();if (isPushingRtmp || isRTSPPublisherRunning || isGB28181StreamRunning || isRecording) {if (libPublisher != null) {Image.Plane[] planes = image.getPlanes();int w = image.getWidth(), h = image.getHeight();int y_offset = 0, u_offset = 0, v_offset = 0;if (!crop_rect.isEmpty()) {// 裁剪测试++, 视频中心裁剪320*180一块区域/*crop_rect.left = image.getWidth()/2 - 320/2;crop_rect.top = image.getHeight()/2 - 180/2;crop_rect.right = crop_rect.left + 320;crop_rect.bottom = crop_rect.top + 180;*/// 裁剪测试--w = crop_rect.width();h = crop_rect.height();y_offset += crop_rect.top * planes[0].getRowStride() + crop_rect.left * planes[0].getPixelStride();u_offset += (crop_rect.top / 2) * planes[1].getRowStride() + (crop_rect.left / 2) * planes[1].getPixelStride();v_offset += (crop_rect.top / 2) * planes[2].getRowStride() + (crop_rect.left / 2) * planes[2].getPixelStride();;// Log.i(TAG, "crop w:" + w + " h:" + h + " y_offset:"+ y_offset + " u_offset:" + u_offset + " v_offset:" + v_offset);}int scale_w = 0, scale_h = 0, scale_filter_mode = 0;scale_filter_mode = 3;int rotation_degree = cameraImageRotationDegree_;if (rotation_degree < 0) {Log.i(TAG, "onCameraImageData rotation_degree < 0, may need to set orientation_ to 0, 90, 180 or 270");return;}libPublisher.PostLayerImageYUV420888ByteBuffer(publisherHandle, 0, 0, 0,planes[0].getBuffer(), y_offset, planes[0].getRowStride(),planes[1].getBuffer(), u_offset, planes[1].getRowStride(),planes[2].getBuffer(), v_offset, planes[2].getRowStride(), planes[1].getPixelStride(),w, h, 0, 0,scale_w, scale_h, scale_filter_mode, rotation_degree);}}}
对应的接口设计如下:
/*** 投递层YUV420888图像, 专门为android.media.Image的android.graphics.ImageFormat.YUV_420_888格式提供的接口** @param index: 层索引, 必须大于等于0** @param left: 层叠加的左上角坐标, 对于第0层的话传0** @param top: 层叠加的左上角坐标, 对于第0层的话传0** @param y_plane: 对应android.media.Image.Plane[0].getBuffer()** @param y_offset: 图像偏移, 这个主要目的是用来做clip的,一般传0** @param y_row_stride: 对应android.media.Image.Plane[0].getRowStride()** @param u_plane: android.media.Image.Plane[1].getBuffer()** @param u_offset: 图像偏移, 这个主要目的是用来做clip的,一般传0** @param u_row_stride: android.media.Image.Plane[1].getRowStride()** @param v_plane: 对应android.media.Image.Plane[2].getBuffer()** @param v_offset: 图像偏移, 这个主要目的是用来做clip的,一般传0** @param v_row_stride: 对应android.media.Image.Plane[2].getRowStride()** @param uv_pixel_stride: 对应android.media.Image.Plane[1].getPixelStride()** @param width: width, 必须大于1, 且必须是偶数** @param height: height, 必须大于1, 且必须是偶数** @param is_vertical_flip: 是否垂直翻转, 0不翻转, 1翻转** @param is_horizontal_flip:是否水平翻转, 0不翻转, 1翻转** @param scale_width: 缩放宽,必须是偶数, 0或负数不缩放** @param scale_height: 缩放高, 必须是偶数, 0或负数不缩放** @param scale_filter_mode: 缩放质量, 传0使用默认速度,可选等级范围是:[1,3],值越大缩放质量越好, 但速度越慢** @param rotation_degree: 顺时针旋转, 必须是0, 90, 180, 270, 注意:旋转是在缩放, 垂直/水品反转之后再做, 请留意顺序** @return {0} if successful*/public native int PostLayerImageYUV420888ByteBuffer(long handle, int index, int left, int top,ByteBuffer y_plane, int y_offset, int y_row_stride,ByteBuffer u_plane, int u_offset, int u_row_stride,ByteBuffer v_plane, int v_offset, int v_row_stride, int uv_pixel_stride,int width, int height, int is_vertical_flip, int is_horizontal_flip,int scale_width, int scale_height, int scale_filter_mode,int rotation_degree);
总结
无需赘述,看过以上两个接口后,是不是觉得,即使数据需要更客制化的处理,比如缩放、水平翻转、垂直翻转、旋转等,也都可以实现?
实际上,数据源这块,不止Android自带的采集设备,其他编码前数据类型(如YV12/NV21/NV12/I420/RGB24/RGBA32/RGB565),均可实现更精细的处理。