Free online H264 to AVC converter

Programs that label the required video codec as AVC may reject a file named or packaged as H264, especially when they expect an .avc elementary stream. Because H.264 and AVC are names for the same video standard, this task usually requires repackaging or renaming rather than a different codec.

What the H264 format is

H264 is the common filename and codec label for H.264/MPEG-4 AVC, a video compression standard used by cameras, phones, screen recorders, streaming software, and editing applications. Files may contain a raw H.264 elementary stream with an .h264 extension, or H.264 video inside an MP4, MOV, MKV, or TS container.

FFmpeg, OBS Studio, VLC recording, Adobe Premiere Pro, DaVinci Resolve, security cameras, and many mobile devices can create H.264 video. The extension alone does not identify the container, audio tracks, frame rate, or profile.

What the AVC format is

AVC means Advanced Video Coding, the formal name of H.264. An .avc file normally contains a raw AVC/H.264 video stream without a container, while some applications use “AVC” only as a codec label for video stored in MP4 or another container.

AVC is used when a device, broadcast workflow, embedded player, or media-analysis tool specifically expects the H.264 stream format. It supports common profiles such as Baseline, Main, and High, but compatibility also depends on resolution, frame rate, level, pixel format, and whether the stream uses Annex B or length-prefixed NAL units.

How to actually convert H264 to AVC

Use the built-in online converter

On 101convert.com, open the video converter, upload the H264 file, select AVC as the output format, and start the conversion. Download the resulting file when processing finishes; no software installation is required.

Copy the existing video stream with FFmpeg

Since H264 and AVC are identical standards, stream copying is preferable when the source already contains compatible H.264 video:

ffmpeg -i input.h264 -c:v copy -f h264 output.avc

This writes a raw AVC/H.264 stream and does not include audio. To extract H.264 video from a container without re-encoding it, use:

ffmpeg -i input.mp4 -an -c:v copy -f h264 output.avc

If the receiving application actually expects H.264 video in an MP4 container rather than a raw .avc stream, remux it instead:

ffmpeg -i input.h264 -c:v copy -an output.mp4

Some raw streams need the input format specified explicitly:

ffmpeg -f h264 -i input.h264 -c:v copy -f h264 output.avc

Re-encode only when compatibility requires it

If the source profile, pixel format, level, or bitstream structure is rejected, encode a new AVC stream:

ffmpeg -i input.h264 -c:v libx264 -preset medium -crf 18 -pix_fmt yuv420p -f h264 output.avc

Use a higher CRF such as 23 for a smaller file, or a lower value for higher quality. Re-encoding takes longer and cannot restore detail already lost in the source.

Quality, compatibility, and limitations

A direct stream copy causes no generational quality loss because the compressed video data is unchanged. Renaming .h264 to .avc may be sufficient only when both files are raw streams and the receiving software identifies the format by extension; it does not change container structure or codec parameters.

Raw AVC files generally lack audio, timestamps, subtitles, metadata, and seeking information. Use MP4 when those features are required. If playback fails after copying, inspect the source with ffprobe input.h264 and check the target device’s required H.264 profile, level, frame size, frame rate, and pixel format.