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 devices export strangely labeled footage even when the underlying format is normal, meaning a video might just need to be renamed to .mp4 to play, though other cases require the manufacturer’s player to convert it; the fastest way to tell is to test it in VLC, check codec info, or use MediaInfo to confirm whether it’s a proper container (MP4/MKV/TS) and whether audio exists, and if it turns out to be a raw AVC stream you typically need to place it into an MP4 for improved compatibility and seekability.

A `.mp4` file is normally a standard MP4 *container*, offering organized video, audio, timing, indexing, subtitles, and metadata, but a `. If you are you looking for more info regarding AVC file program review the web site. avc` file is frequently just a raw H.264/AVC stream or device-specific output with none of that structure; it can decode, yet players might show slow seeking because essential container-level information is absent.

This is also why `.avc` files commonly contain no accompanying soundtrack: 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 well-indexed structure, while `.avc` often suggests vendor-specific wrapping, which leads to missing audio and poor seek accuracy.

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 wrapping it into MP4 without re-encoding is the usual fix, giving it the indexing and timing data it lacks.

If the file comes from a CCTV/DVR or a system with its own wrapper, the safest approach is usually using the vendor’s playback/export tool to create an MP4 or AVI, since some proprietary formats won’t convert smoothly without a correct export; in those situations you’re converting from a custom structure into a standard container rather than just renaming, and if playback is corrupted, won’t open, or the duration stays wrong even after remuxing, it often means the recording is incomplete or missing companion index files, so the real fix is re-exporting from the device or finding the required metadata files.