Free online 264 to WEBM converter

A file ending in .264 is usually a raw H.264 video stream, while WebM requires VP8, VP9, or AV1 video. Convert it when a browser, web player, video editor, or publishing workflow accepts WebM but does not accept the original H.264 stream.

What the 264 format is

.264 is generally a filename extension for an H.264/AVC elementary stream, not a complete container format. It commonly comes from security cameras, DVR and NVR systems, screen-recording software, encoder tools, and device exports. FFmpeg and some hardware encoders can also write raw H.264 streams.

A raw stream may contain video only and may lack timestamps, metadata, subtitles, and audio. Some devices use .264 for proprietary recordings or for H.264 data that is actually packaged in an MP4-like container, so inspect the file before choosing conversion settings.

What the WEBM format is

WebM is a multimedia container designed mainly for web playback. Its standard video codecs are VP8, VP9, and AV1; its usual audio codecs are Vorbis and Opus. H.264 video cannot simply be renamed to .webm or copied into a standard WebM file, so the video normally requires re-encoding.

WebM is useful for HTML5 video, browser-based applications, web publishing, and projects that prefer royalty-free codecs. VP9 and AV1 can produce smaller files than H.264 at comparable quality, but encoding takes longer and older hardware may decode them less efficiently.

How to convert 264 to WEBM

For a local conversion, FFmpeg is the most flexible desktop tool. First check whether the input is a raw H.264 stream:

ffprobe input.264

If FFprobe identifies H.264 video without a container, convert it to VP9 WebM with:

ffmpeg -f h264 -i input.264 -c:v libvpx-vp9 -crf 32 -b:v 0 -c:a libopus -b:a 128k output.webm

Raw .264 files often contain no audio, in which case omit the audio option:

ffmpeg -f h264 -i input.264 -c:v libvpx-vp9 -crf 32 -b:v 0 output.webm

The -crf value controls quality in constant-quality mode: lower values produce better quality and larger files. A practical VP9 range is 28–36; test a short sample before converting a large recording. To produce a faster, larger file, use a bitrate instead:

ffmpeg -f h264 -i input.264 -c:v libvpx-vp9 -b:v 2M -c:a libopus -b:a 128k output.webm

To preserve the original H.264 stream for a compatible Matroska-based workflow, use .mkv rather than WebM; standard WebM playback should use VP8, VP9, or AV1.

If you do not want to install software, you can convert the file for free on the 101convert.com website. Upload the recording, select WEBM as the output, start the conversion, and download the result. Large surveillance files may exceed upload limits or take longer to process online.

Quality, compatibility, and limitations

Re-encoding H.264 to VP9 or AV1 is lossy, so the output cannot restore detail already discarded by the source. Avoid unnecessary generations and retain the original .264 file as the archival master.

Raw H.264 may have unreliable or missing frame-rate information. If playback is too fast, too slow, or out of sync, provide the expected frame rate, for example -framerate 25, before the input:

ffmpeg -f h264 -framerate 25 -i input.264 -c:v libvpx-vp9 -crf 32 -b:v 0 output.webm

Some device exports are encrypted, fragmented, or proprietary and cannot be decoded directly by FFmpeg. In that case, export the recording through the camera or DVR manufacturer's software first. Verify the resulting file with ffprobe output.webm and test it in the browser or editor that will use it.