![]() Keep in mind, however, complexity has a cost, and not every file format has to, or should, support everything. Often AVI gets a lot of flak for not supporting a lot of newer video storage functionality, such as subtitles, timestamps, and more complex frame dependencies. Overall, AVI isn't a very complex file format, and in particular it's very easy to write - so it's not surprising that a lot of programs support it. Lose the headers at the start, and your file is unusable. Lose the index at the end, and your AVI file will become unseekable or even refuse to play in some players. Note that the header and index are at the beginning and end of the file.That would be very slooooooooIn fact, it is the ONLY chunk in this file that does. Without this chunk, the only way to find frame 400 would be to run forward through all the chunks in the 'movi' LIST and count them until you hit the 401st video frame. The 'idx1' index lists all of the chunks in the main 'movi' LIST, which in turn holds all audio and video frames.Note that despite common belief, the interleaving of audio and video chunks has nothing to do with the timing of the streams, and thus no effect on sync. This isn't too important for playback from a hard disk, and modern players are very good at handling non-interleaved or badly interleaved files, but proper interleaving is critical for proper playback in embedded devices and CD-ROM playback. The reason for it is so that a player can read the AVI file sequentially and pick up the audio and video it needs without seeking all over the place. This is the 'interleaved' part of the file. Audio and video data are broken into blocks and mixed together each video frame has its own chunk, but audio data is organized in small packets.They won't play that well given that AVI doesn't interleave data finely enough, doesn't have scrambling mechanisms for enhanced audio error masking and doesn't have a rigid enough structure for good error recovery, but you can do it. ![]() (This isn't actually true of MUSTUSEINDEX is set in the stream header, but I've never seen this used.) Combined with the header being at the front this means that AVI files can actually be played in streaming mode across a network. Audio and video data is stored in the 'movi' LIST chunk in chronological order.(VirtualDub's AVI parser supports multi-video and multi-audio stream AVIs it's the UI and output modules that don't.) You can actually store text streams and even multiple video and audio streams in a single AVI file. AVI files are composed of general streams this one consists of one video and one audio stream.
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