Extract the video keyframe

I want to ask the way that extract to keyframes of long video. The video is color not gray, so I think that so difficult. I try to use entropy way to extract keyframe but I false. :( Pleas tell me how to do and any way. Thank you!

Answer 1

[Walter Roberson]

There is no single way to calculate IBP frames: they are always generated as trade-offs between the data carrying capacity of the channel and the computational capacity of the decoder.

Every frame can be treated as a key frame, if the data throughput is high enough (e.g., disc reading speed is high.)

There is no method to read the frames from a video and figure out from the decoded frames which of the frames were stored as key frames in the video -- not unless you have complete specification of the frame encoding algorithm (which would often be implementation-specific as there are a number of things which are parameters of the system rather than being fixed specifications.) There is no "marker" or "header" of any kind in the decoded frames as to how the frame was encoded on the video.

[Walter Roberson]

If you had complete specifications of the video file format and the decoder, then you could read the binary file of the video and look at the information stored there to find the key frames at that level. The File Exchange has an MPEG reader that could be extended or adapted for AVI use. But more typical, due to the work involved, would be to link to a C or C++ library that understands the format and use it to find the keyframes.