AVC generally means H.264/AVC video compression, which is the encoding layer, not the wrapper, while the actual file format is usually a container like MP4, MKV, MOV, or TS that can hold AVC video along with audio tracks such as AAC, so people sometimes mix things up and label an MP4 as "an AVC file" despite the container defining the type; files ending in .avc or .h264/. If you have any thoughts relating to the place and how to use file extension AVC, you can get in touch with us at our own web site. 264 usually contain raw AVC streams or custom exports that VLC may handle but often with weak seeking, incorrect duration, or no audio due to missing container-level indexing.
Some CCTV/DVR setups label standard footage with unusual extensions even when the data is perfectly normal, so simply renaming to .mp4 may fix playback, while other clips are proprietary and need the vendor tool to convert; the simplest way to identify the format is to load it in VLC, view codec info, or check with MediaInfo to see if it’s a true container (MP4/MKV/TS), and if it shows a raw AVC stream the typical solution is to recontainerize it into MP4 to get better compatibility and seeking.

A `.mp4` file generally provides a complete MP4 *container* with video, audio, subtitles, metadata, and timing/index data that ensures smooth playback, while a `.avc` file often signals a raw AVC bitstream lacking container features; it may still display video, but players can struggle with starting cleanly due to missing structural cues.
This is also why `.avc` recordings often have no audio track included: audio wasn’t packaged or lives separately, whereas MP4 generally combines video and audio; plus, many CCTV/DVR systems output bizarre extensions, so a file might actually be MP4/TS but mislabeled and fixed by renaming, while others rely on proprietary wrappers needing vendor software; put simply, `.mp4` means proper multimedia packaging, and `.avc` usually means raw H.264 video, which explains missing audio, limited seeking, and compatibility problems.
Once you’ve identified whether your "AVC file" is mislabeled, raw H.264, or proprietary, the correct approach becomes clear; if MediaInfo/VLC indicates a normal container like MP4—signs include "Format: MPEG-4" or smooth navigation—renaming the extension from `.avc` to `.mp4` is often enough, ideally after copying the file; if the file is a raw AVC stream (you’ll usually see "Format: AVC" with scant container details and awkward seeking), then recontainerizing it into MP4 without re-encoding is the usual fix, giving it the indexing and timing data it lacks.
If the file originated from a CCTV/DVR or another system using a proprietary wrapper, the most dependable method is running it through the vendor’s export tool to MP4 or AVI, because certain closed formats don’t wrap correctly without a proper export; in those cases you’re converting from a special structure to a standard one rather than renaming, and if playback still fails, won’t open, or shows incorrect duration after remuxing, it usually signals corruption or missing sidecar/index files, meaning you must re-export from the source or retrieve the matching metadata.