Editing Audio Video Interleave (section)

==Format==
AVI is a subformat of the [[RIFF (File format)|Resource Interchange File Format]] (RIFF), which divides a file's data into blocks, or "chunks". Each chunk is identified by a [[FourCC]] tag.<ref name=Gloe-2014>{{cite journal|title=Forensic analysis of video file formats § AVI Container format|last=Gloe|first=Thomas|journal=Digital Investigation|publisher=[[Elsevier]]|date=2014-04-16|volume=11|issue=1|doi=10.1016/j.diin.2014.03.009|issn=1742-2876|doi-access=free}}</ref>

An AVI file takes the form of a RIFF header, which is then divided into two mandatory chunks and one optional chunk. The first chunk is identified by the "hdrl" tag, which stores the information required by the codec to decompress the AVI file for viewing. The second sub-chunk is identified by the "movi" tag, containing the actual audio and visual data that make up the AVI video. The third optional chunk is identified by the "idx1" tag, which indexes the [[offset (computer science)|offsets]] of the data chunks within the file.<ref name=Gloe-2014/>

By way of the RIFF format, the audio and visual data contained in the "movi" chunk can be encoded or decoded by software called a [[codec]], which is an abbreviation for (en)coder/decoder. Upon creation of the file, the codec translates between raw data and the (compressed) data format used inside the chunk. An AVI file may carry audio and visual data inside the chunks in virtually any compression scheme, including Full Frame (Uncompressed), [[Indeo]], [[run-length encoding]], and [[Microsoft Video 1]].<ref name=Quain-1993/>

Some programs, like [[VLC media player|VLC]], complain when the "idx1" index sub-chunk is not found, as it is required for efficient moving among timestamps. They offer to "fix" the file by building an index temporarily or permanently.<ref>{{cite web |title=WindowsFAQ-1.1.x |url=https://wiki.videolan.org/WindowsFAQ-1.1.x#Can_I_fix_those_broken_AVI_files_permanently.3F |website=VideoLAN Wiki}}</ref>{{Better source needed|date=September 2021|reason=Wiki sources are unrelieble per WP:SPS.}}