AVC commonly refers to H.264/AVC, a video codec rather than a file container, and most videos you encounter are actually MP4, MKV, MOV, or TS containers that simply include an AVC-encoded track plus audio, which creates the habit of calling the entire file an "AVC file" even though the container is what defines the file type; when the extension is .avc or .h264/.264, it often signals a raw bitstream or device-specific output that VLC may play but with limited seeking, inaccurate timing, or no audio because true containers provide indexes and multiple streams.

Some CCTV/DVR systems output strangely named files even when the contents are standard, so a clip may be incorrectly labeled and work once renamed to .mp4, though some files are truly proprietary and require the vendor’s player to re-export; the quickest way to check is to open it in VLC, inspect codec details, or run MediaInfo to see if it’s a real container like MP4/MKV/TS with audio, in which case renaming often helps, while raw AVC streams usually need to be remuxed into an MP4 container for better compatibility and seeking without re-encoding.

A `.mp4` file is typically a full MP4 *container* that stores not just AVC/H. If you liked this article and you would like to acquire more info with regards to AVC file type nicely visit the website. 264 video but also timing data, indexes for smooth seeking, audio tracks, subtitles, and metadata, while a `.avc` file is often a raw H.264/AVC bitstream or device-specific export that lacks container structure; it can still play because frames exist, but players may struggle with accurate duration since key structural info is missing.

This is also why `.avc` files commonly contain no embedded audio: audio may not be bundled and might live elsewhere, while MP4 typically includes both; further confusion comes from CCTV/DVR exports that use nonstandard extensions, meaning a mislabeled `.avc` might behave normally if renamed to `.mp4`, though some require proprietary exporters; overall, `.mp4` suggests complete multimedia packaging, while `.avc` often suggests vendor-specific wrapping, which leads to missing audio and poor seek accuracy.

Once you know whether the "AVC file" is simply mislabeled, a raw stream, or something proprietary, you can choose the right fix; if tools like VLC or MediaInfo report a standard container such as MP4—e.g., "Format: MPEG-4" or normal playback—renaming `.avc` to `.mp4` often restores compatibility (copy the file first), but if it’s a raw H.264 bitstream, usually indicated by "Format: AVC" with little structural info and shaky seeking, the standard solution is to move it into an MP4 container without re-encoding to supply proper timing and indexing.

If the clip was generated by a CCTV/DVR or similar device with a custom wrapper, the best solution is to use the official viewer/export tool to produce an MP4 or AVI, since some proprietary formats refuse to wrap successfully until they’re exported properly; here you’re converting from a unique structure to a standard container, not just renaming, and if playback breaks, won’t load, or the timing is still wrong after remuxing, it likely points to corruption or absent companion files, making a new export or locating the index/metadata files necessary.