Change Buffer format of DJIVideoPreviewer

[ynaka01-max]

Now I am creating app that uses video frame from the DJI aircraft and run it through tensorlite object detection model.

I managed to get my app to receive the frame from the aircraft.

However, frame type is VPFrameTypeYUV420Planer. I want to receive the frame of VPFrameTypeYUV420SemiPlanar. It's because I want to create kCVPixelFormatType_420YpCbCr8BiPlanarFullRange cvPixelBuffer from the frame.

I tried to change videopreviewr property as follows.

DJIVideoPreviewer.instance()?.frameOutputType = VPFrameTypeYUV420SemiPlaner

However, I got error.

I also tried to create kCVPixelFormatType_420YpCbCr8BiPlanarFullRange cvPixelBuffer from YUV420Planer frame. However, I don't know how to convert chromaR, chormaB to UV.

func createPixelBuffer(fromFrame frame: VideoFrameYUV) -> CVPixelBuffer? {
        var initialPixelBuffer: CVPixelBuffer?
        let _: CVReturn = CVPixelBufferCreate(kCFAllocatorDefault, Int(frame.width), Int(frame.height), kCVPixelFormatType_420YpCbCr8BiPlanarFullRange, nil, &initialPixelBuffer)

        guard let pixelBuffer = initialPixelBuffer,
            CVPixelBufferLockBaseAddress(pixelBuffer, []) == kCVReturnSuccess
            else {
                return nil
        }

        let yPlaneWidth = CVPixelBufferGetWidthOfPlane(pixelBuffer, 0)
        let yPlaneHeight = CVPixelBufferGetHeightOfPlane(pixelBuffer, 0)

        let uvPlaneWidth = CVPixelBufferGetWidthOfPlane(pixelBuffer, 1)
        let uvPlaneHeight = CVPixelBufferGetHeightOfPlane(pixelBuffer, 1)

        let yDestination = CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 0)
        memcpy(yDestination, frame.luma, yPlaneWidth * yPlaneHeight)

        let uvDestination = CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 1)

       // let chrB = frame.chromaB.pointee
//        let chrR = frame.chromaR.pointee
        // I don't know how to convert to uv Buffer.

        CVPixelBufferUnlockBaseAddress(pixelBuffer, [])

        return pixelBuffer

Is there good way to solve this problem?

[laohongshu]

func createPixelBuffer(fromFrame frame: VideoFrameYUV) -> CVPixelBuffer? { var initialPixelBuffer: CVPixelBuffer? let _: CVReturn = CVPixelBufferCreate(kCFAllocatorDefault, Int(frame.width), Int(frame.height), kCVPixelFormatType_420YpCbCr8BiPlanarFullRange, nil, &initialPixelBuffer) guard let pixelBuffer = initialPixelBuffer, CVPixelBufferLockBaseAddress(pixelBuffer, []) == kCVReturnSuccess else { return nil }

//get y plane size let yPlaneWidth = CVPixelBufferGetWidthOfPlane(pixelBuffer, 0) let yPlaneHeight = CVPixelBufferGetHeightOfPlane(pixelBuffer, 0) let yDestination = CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 0) memcpy(yDestination, frame.luma, yPlaneWidth * yPlaneHeight)

//get u plane size let uPlaneWidth = CVPixelBufferGetWidthOfPlane(pixelBuffer, 1) let uPlaneHeight = CVPixelBufferGetHeightOfPlane(pixelBuffer, 1) let uDestination = CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 1) memcpy(uDestination, frame.chromaB, uPlaneWidth * uPlaneHeight)

//get v plane size let vPlaneWidth = CVPixelBufferGetWidthOfPlane(pixelBuffer, 2) let vPlaneHeight = CVPixelBufferGetHeightOfPlane(pixelBuffer, 2) let vDestination = CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 2) memcpy(vDestination, frame.chromaR, vPlaneWidth * vPlaneHeight)

CVPixelBufferUnlockBaseAddress(pixelBuffer, []) return pixelBuffer

}

[EXEShirley]

Now I am creating app that uses video frame from the DJI aircraft and run it through tensorlite object detection model.

I managed to get my app to receive the frame from the aircraft.

However, frame type is VPFrameTypeYUV420Planer. I want to receive the frame of VPFrameTypeYUV420SemiPlanar. It's because I want to create kCVPixelFormatType_420YpCbCr8BiPlanarFullRange cvPixelBuffer from the frame.

I tried to change videopreviewr property as follows.

DJIVideoPreviewer.instance()?.frameOutputType = VPFrameTypeYUV420SemiPlaner

However, I got error.

I also tried to create kCVPixelFormatType_420YpCbCr8BiPlanarFullRange cvPixelBuffer from YUV420Planer frame. However, I don't know how to convert chromaR, chormaB to UV.

func createPixelBuffer(fromFrame frame: VideoFrameYUV) -> CVPixelBuffer? {
        var initialPixelBuffer: CVPixelBuffer?
        let _: CVReturn = CVPixelBufferCreate(kCFAllocatorDefault, Int(frame.width), Int(frame.height), kCVPixelFormatType_420YpCbCr8BiPlanarFullRange, nil, &initialPixelBuffer)

        guard let pixelBuffer = initialPixelBuffer,
            CVPixelBufferLockBaseAddress(pixelBuffer, []) == kCVReturnSuccess
            else {
                return nil
        }

        let yPlaneWidth = CVPixelBufferGetWidthOfPlane(pixelBuffer, 0)
        let yPlaneHeight = CVPixelBufferGetHeightOfPlane(pixelBuffer, 0)

        let uvPlaneWidth = CVPixelBufferGetWidthOfPlane(pixelBuffer, 1)
        let uvPlaneHeight = CVPixelBufferGetHeightOfPlane(pixelBuffer, 1)

        let yDestination = CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 0)
        memcpy(yDestination, frame.luma, yPlaneWidth * yPlaneHeight)

        let uvDestination = CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 1)

       // let chrB = frame.chromaB.pointee
//        let chrR = frame.chromaR.pointee
        // I don't know how to convert to uv Buffer.

        CVPixelBufferUnlockBaseAddress(pixelBuffer, [])

        return pixelBuffer

Is there good way to solve this problem?

1.frameOutputType is read-only attribute，we cannot set output yuv format. 2.When using hardware decoder, VPFrameTypeYUV420SemiPlanar is the output format. Please make sure you are not using simulator. In the meantime, enableFastUpload and enableHardwareDecode in VideoPreviewer should be set as YES.