问题
I am currently trying to make some modifications to the incoming WebRTC video stream in the AppRTC app for iOS in Swift (which in turn is based on this Objective-C version). To do so, I need access to the data which is stored in the frame objects of class RTCI420Frame (which is a basic class for the Objective-C implementation of libWebRTC). In particular, I need an array of bytes: [UInt8] and Size of the frames. This data is to be used for further processing & addition of some filters.
The problem is, all the operations on RTCVideoTrack / RTCEAGLVideoView are done under the hood of pre-compiled libWebRTC.a, it is compiled from the official WebRTC repository linked above and it's fairly complicated to get a custom build of it, so I'd prefer to go with the build available in the example iOS project; in my understanding it's supposed to have all the available functionality in it.
I was looking into RTCVideoChatViewController class and in particular, remoteView / remoteVideoTrack, but had no success in accessing the frames themselves, spent a lot of time researching the libWebRTC sources in official repo but still can't wrap my head around the problem of accessing the frames data for own manipulations with it. Would be glad for any help!
回答1:
Just after posting the question I had a luck in finding the sneaky data!
You have to add the following property to RTCEAGLVideoView.h file:
@property(atomic, strong) RTCI420Frame* i420Frame;
In the original implementation file there is the i420Frame property but it wasn't exposed in the iOS project's header file for the class. Adding the property allows you to get view's current frame.
I'm still in search of a more elegant way of getting the stream data directly, without the need to look into remoteView contents, will update the answer once I find it.
来源：https://stackoverflow.com/questions/39134537/how-to-get-frame-data-in-apprtc-ios-app-for-video-modifications