Yesterday I've decided to share all my home code using Project Hosting on Google Code, so now everyone can browse my code online by entering project called blueway. I'll be very glad to hear your opinions and suggestions about it.
Today I've researched subject of generating video data as AVI file, compressed on the fly with codecs installed in Windows. After succeeding with that I've created simple class to support this task, called VideoCompressor. You can find it in Video.hpp and Video.cpp. Test code is in ProgramMain.cpp, line 2318. It generates a 5 second video with a white horizonal line moving from bottom to top.
Here are some technical details. Functionality needed to handle video files is already inside Windows API, described in MSDN Library. The AVIFile library contains functions like AVIFileOpen, AVIFileCreateStream, AVIStreamWrite. It supports reading and writing AVI files. You need to include <Vfw.h> header and link with Vfw32.lib file. AVI is actually a container file format made of RIFF data chunks identified by 4-byte FOURCC codes (if you ever loaded 3DS models, you know what I mean). It can contain multiple streams like video and audio, which can be coded in many different formats, compressed and decompressed by codecs.
Compressing and decompressing frames of video with installed codecs can be done with Video Compression Manager library. You can display standard, system dialog window to let the user choose and configure codec with ICCompressorChoose function. Then you can just pass subsequent video frames as uncompressed RGB images to a function like ICSeqCompressFrame and you get a piece of compressed data that you can save to your AVI file.