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This and following sections describe the chunks contained in the LIST 'hdrl' and LIST 'movi' chunks. The 'idx1' chunk is not described in this document. For more information on the 'idx1' chunk and indexes in AVI files, see version 1.02 of the OpenDML AVI File Format Extensionspublished by the OpenDML AVI M-JPEG File Format Subcommittee, February 28, 1996.
The file begins with the main header. In the AVI file, this header is identified by the 'avih' FOURCC (four-character code). The header contains global information for the entire AVI file, such as the number of streams within the file and the width and height of the AVI sequence. The AVI main header structure is defined as follows:
typedef struct { DWORD dwMicroSecPerFrame ; DWORD dwMaxBytesPerSec ; DWORD dwReserved1 ; DWORD dwFlags ; DWORD dwTotalFrames ; DWORD dwInitialFrames ; DWORD dwStreams ; DWORD dwSuggestedBufferSize ; DWORD dwWidth ; DWORD dwHeight ; DWORD dwReserved [4]; } MainAVIHeader;
Flag | Description |
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AVIF_HASINDEX | Indicates the AVI file has an 'idx1' chunk containing an index at the end of the file. For good performance, all AVI files should contain an index. |
AVIF_MUSTUSEINDEX | Indicates that the index, rather than the physical ordering of the chunks in the file, should be used to determine the order of presentation of the data. For example, you could use this to create a list of frames for editing. |
AVIF_ISINTERLEAVED | Indicates the AVI file is interleaved. |
AVIF_WASCAPTUREFILE | Indicates the AVI file is a specially allocated file used for capturing real-time video. Applications should warn the user before writing over a file with this flag set because the user probably defragmented this file. |
AVIF_COPYRIGHTED | Indicates the AVI file contains copyrighted data and software. When this flag is used, software should not permit the data to be duplicated. |
Last updated on Tuesday, May 18, 2004