Accessing & Manipulating video frames from .mp4 fi

问题:

As you may know, when you record a video on a windows phone, it is saved as a .mp4. I want to be able to access the video file (even if it's only stored in isolated storage for the app), and manipulate the pixel values for each frame.

I can't find anything that allows me to load a .mp4 into an app, then access the frames. I want to be able to save the manipulated video as .mp4 file as well, or be able to share it.

Has anyone figured out a good set of steps to do this? My guess was to first load the .mp4 file into a Stream object. From here I don't know what exactly I can do, but I want to get it into a form where I can iterate through the frames, manipulate the pixels, then create a .mp4 with the audio again once the manipulation is completed.

回答1:

I tried doing the exact same thing once. Unfortunately, there are no publicly available libraries that will help you with this. You will have to write your own code to do this.

The way to go about this would be to first read up on the storage format of mp4 and figure out how the frames are stored there. You can then read the mp4, extract the frames, modify them and stitch them back in the original format.

My biggest concern is that the hardware might not be powerful enough to accomplish this in a sufficiently small amount of time.