how to use ffmpeg to encrypt both the i-frame and p-frame?

[shredding]

We have codes that can read a video stream and extract frames out of the stream. After extracting the raw video frames, we encrypt it (both the p-frame or i-frames) and then save the encrypted frames to a new video file. We found that if we encrypt the I-frames as well as the p-frames, the encrypted videos can’t be played back correctly (we have decryption at the playback stage. The video just looks like it has no i-frames and only the p-frames are played back with all the shades). But when we encrypt the p-frames only, the playback can be done correctly. (We use SDL for frame displaying).

How can we write a player that can playback the encrypted video that has both i-frame and p-frame encrypted.

For each packet, we feed the packet data to the encoder/decoder:

// Is this a packet from the video stream?
if(packet.stream_index==videoStream) {
// Decode video frame
avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished,
&packet);

[zing269]

Make sure that any other frames that your i-frame references are decrypted.

[abeer]

i need codes that can read a video stream and extract frames out of the stream, I,P,B frames , and i want it under windows,
please any body can help me