hello, i don't know much about hardware, since actually i don't really like it, so if i am going to ask a dump question, then i apologise first. as we know, games heavily involve in computer graphics will normally require a good graphic card with suitable number of rams. my question is whether the graphic card has anything to do with the movie files (eg. mp4, mpeg, rm, avi, etc.) also, if we don't have a graphic card, do we still able to watch movies? thanks

Your graphics card handles everything that is displayed on your screen, including movies, Just as your sound card handles everything that comes out of the speakers. Without a graphics card, you wouldn't even have a place to plug in your monitor, much less be able to watch movies. Movies typically have less strict requirements on a graphics card...I think you need at least 8MB to watch a DVD (MPEG2). HTH, -SN

Intel has an integrated graphics card on many of their motherboards. It functions reasonably well, but is not equivalent to offerings from ATI or Nvidia. Those cards are actually motherboards unto themselves with their own RAM, GPU, and sometimes ports. An ATI 9800 will have many smaller processors on it leading to a framebuffer of DDR memory, for example. Displaying computer games (specifically 3D) is much more complicated than displaying a movie. For a game, the CPU will stage instructions based on the game code to the video card, which then goes through a pipeline of steps (calculating transformations of geometry to two dimensions for the monitor, shading/lighting, anti-aliasing, and other tasks). The final output lands in the frame buffer, which is an abstract place in memory (usually the video card's memory) which contains the next image to be displayed on the screen. This is refreshed many times a second and constantly fed to the monitor. Video playback has different operations leading up to the framebuffer. It is traditionally largely reliant on the main board CPU. For playback, the CPU is decompressing an encoded file. The codec, which defines the encoding, is a compression format with a set framerate, frame display, and memory size (as well as other details like special types of frames to ensure consistent playback). The video is effectively streamed from the data source. Because the codec is designed to support a maximum resolution and frame memory size, uniformity allows for a simpler execution. There are no complex transformations necessary - the data is clearly defined and decompression is straightforward. Software libraries play the critical role in video playback. MPEG4/MP4 is actually built after the Quicktime format, which is itself part of a powerful multimedia library Apple has ported with its QT player. MPEG 1, 2, and 3 are video/audio encoding formats designed mostly for high quality video/audio. MPEG 2 is common for things like HDTV feed. AVI files are a standard started by Microsoft and adopted by parts of the industry (audio and video are not seperated into layers, but interleaved). Incidentally, MP3's come from MPEG 1 Layer III encoding (the audio layer) which has existed formally from 1992.

Thanks very much to both of you. I have a clear idea now :)