AVC generally means H.264/AVC video compression, which is the codec responsible for compression, 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/.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 systems assign nonstandard file types though the video may still be standard, allowing a rename to .mp4 to work, while others need the manufacturer’s software to re-export; to identify the type quickly, open in VLC, check codec info, or run MediaInfo to see if it’s a normal container with audio, and if it shows as a raw AVC stream you typically wrap it into an MP4 container to improve seeking and compatibility without recompression.
A `.mp4` file is almost always a true MP4 *container* holding compressed video plus audio, subtitle tracks, metadata, and seek/timing structure, whereas a `.avc` file is often merely a raw H.264/AVC stream or vendor-specific output; although playable, it commonly leads to strange initial playback because container elements aren’t present.
This is also why `.avc` files often end up with video-only content: audio may be separate or never embedded, unlike MP4 which usually carries both video and audio; on top of that, many CCTV/DVR exporters use odd extensions, so a mislabeled `.avc` might actually be MP4/TS and start working once renamed, while truly proprietary ones need the vendor’s app to convert; basically, `.mp4` means standard container structure, whereas `.avc` often means video-only data, resulting in missing audio and unreliable seeking.
Once you’ve determined whether the “AVC file” is mislabeled, raw H. When you have almost any concerns about where by along with the best way to work with AVC file unknown format, it is possible to e mail us in our own page. 264, or proprietary, you can pick the right fix; when VLC/MediaInfo shows a standard container—look for “Format: MPEG-4” or normal seek behavior—just renaming the `.avc` to `.mp4` often restores compatibility (after copying it), but if the file is a raw H.264 stream indicated by “Format: AVC” with sparse container details and erratic seeking, then the usual remedy is to repackage it into an MP4 container without re-encoding, adding essential timing and indexing data for proper playback.
If the footage originates from a CCTV/DVR or similar device using a custom container, the surest route is using the vendor tool to export to MP4 or AVI, since some proprietary formats won’t remux properly without an official export; in those cases you’re transforming a proprietary structure into a standard container, and if the file still fails—corrupted playback, no opening, wrong duration post-remux—it typically means incomplete data or missing index files, so the remedy is re-exporting or finding the required companion metadata.