Free online HEVC to WEBM converter

Browsers and web applications commonly expect WebM instead of HEVC video, especially for HTML5 playback and lightweight web publishing. Converting requires transcoding the HEVC stream to VP9 or AV1 because WebM does not generally accept HEVC video.

What the HEVC format is

HEVC (High Efficiency Video Coding), also called H.265, is a video codec designed to deliver similar quality at lower bitrates than H.264. Phones, action cameras, screen-recording tools, drones, and video editors commonly create HEVC files, usually inside .mp4, .mov, or .mkv containers.

HEVC is efficient for camera recording and local storage, but browser support varies by operating system, browser, hardware decoder, and licensing conditions. The filename extension identifies the container, not necessarily the codec; inspect the file with MediaInfo or FFmpeg if its contents are uncertain.

What the WEBM format is

WebM is an open container format intended primarily for web video. Its standard video codecs are VP8, VP9, and AV1; Opus and Vorbis are the usual audio codecs.

WebM is supported directly by modern browsers, HTML5 video players, streaming systems, and many web publishing tools. VP9 usually provides a practical balance of quality, file size, encoding speed, and compatibility, while AV1 can reduce size further at the cost of substantially slower encoding and more demanding playback.

How to actually convert HEVC to WEBM

Using FFmpeg

Install a current FFmpeg build with libvpx-vp9 and libopus enabled, then run:

ffmpeg -i input.mp4 -map 0:v:0 -map 0:a? -c:v libvpx-vp9 -crf 30 -b:v 0 -pix_fmt yuv420p -c:a libopus -b:a 128k output.webm

This decodes the HEVC video, encodes it as VP9, converts audio to Opus, and writes output.webm. The optional audio mapping keeps the command working when the source has no audio track.

For higher video quality and a larger file, use a lower CRF value such as 24. For a smaller file, use a higher value such as 34. With VP9, -b:v 0 enables constant-quality mode; CRF values from roughly 24 to 34 are a practical starting range.

To limit output to a target video bitrate instead, replace the quality settings with a value such as -b:v 2M. To encode with AV1 when your FFmpeg build supports it, use -c:v libaom-av1 -crf 30 -b:v 0, but expect much longer encoding times.

Using the online converter

You can convert the file for free on 101convert.com without installing software: select the HEVC file, choose WEBM as the output format, start the conversion, and download the resulting file. Uploading is unsuitable for confidential footage or very large files because the source must leave your device.

Quality, compatibility, and limitations

This conversion is normally lossy twice: HEVC is decoded and VP9 or AV1 is encoded again. Keep the original HEVC file when quality preservation matters; increasing the output bitrate cannot restore detail already lost in the source.

WebM commonly uses 8-bit, 4:2:0 video for broad browser compatibility. HDR, 10-bit color, 4:2:2 or 4:4:4 chroma, variable frame rates, rotation metadata, multiple audio tracks, subtitles, and chapter data may be discarded or require separate handling. Check the result with ffprobe output.webm and test it in the browsers or players that will receive it.