I test iOS SDK 4.12 with the Swift Sample Code from DJI.
Xcode 11.4.1
Swift 5

class VideoPreviewerAdapter: NSObject {..

The DJISDKManager.videoFeeder() has no member for

• DJISDKManager.videoFeeder()?.parseDecodingAssistInfo(...
• DJISDKManager.videoFeeder()?.decodingDidSucceed(..
• DJISDKManager.videoFeeder()?.syncDecoderStatus(..
• DJISDKManager.videoFeeder()?.decodingDidFail(..
  

This is new and does not appear in SDK 4.11.1 or lower.

extension VideoPreviewerAdapter: DJIVideoPreviewerFrameControlDelegate {

    func parseDecodingAssistInfo(withBuffer buffer: UnsafeMutablePointer<UInt8>!, length: Int32, assistInfo: UnsafeMutablePointer<DJIDecodingAssistInfo>!) -> Bool {

        return DJISDKManager.videoFeeder()?.parseDecodingAssistInfo(withBuffer: buffer, length: length, assistInfo: assistInfo) ?? false

    }

    func decodingDidSucceed(withTimestamp timestamp: UInt32) {

        DJISDKManager.videoFeeder()?.decodingDidSucceed(withTimestamp: UInt(timestamp))

    }

    func isNeedFitFrameWidth() -> Bool {

        let displayName = VideoPreviewerAdapter.camera()?.displayName

        if displayName == DJICameraDisplayNameMavic2ZoomCamera ||

            displayName == DJICameraDisplayNameMavic2ProCamera {

            return true

        }

        return false

    }

    func syncDecoderStatus(_ isNormal: Bool) {

        DJISDKManager.videoFeeder()?.syncDecoderStatus(isNormal)

    }

    func decodingDidFail() {

        DJISDKManager.videoFeeder()?.decodingDidFail()

    }

}

Fix!

The decode status is linked to the videoFeeder! But it is important to tell if it is the primary or secondary video feed.

Replace DJISDKManager.videoFeeder()?. with feed?

extension VideoPreviewerAdapter: DJIVideoPreviewerFrameControlDelegate {

    func parseDecodingAssistInfo(withBuffer buffer: UnsafeMutablePointer<UInt8>!, length: Int32, assistInfo: UnsafeMutablePointer<DJIDecodingAssistInfo>!) -> Bool {

        return feed?.parseDecodingAssistInfo(withBuffer: buffer, length: length, assistInfo: assistInfo) ?? false

    }

    func decodingDidSucceed(withTimestamp timestamp: UInt32) {

       feed?.decodingDidSucceed(withTimestamp: UInt(timestamp))

    }

    func isNeedFitFrameWidth() -> Bool {

        let displayName = VideoPreviewerAdapter.camera()?.displayName

        if displayName == DJICameraDisplayNameMavic2ZoomCamera ||

            displayName == DJICameraDisplayNameMavic2ProCamera {

            return true

        }

        return false

    }

    func syncDecoderStatus(_ isNormal: Bool) {

        feed?.syncDecoderStatus(isNormal)

    }

    func decodingDidFail() {

        feed?.decodingDidFail()

    }

}

Thanks so much. That worked !