Free online H265 to WEBM converter

What the H.265 format is

H.265, also called HEVC, is a video codec rather than a complete container format. It compresses video more efficiently than H.264 at comparable visual quality, so it is common in 4K recordings, smartphones, action cameras, Blu-ray sources, surveillance systems, and streaming downloads.

HEVC video may be stored in containers such as .mp4, .mkv, or .mov; the filename extension alone does not identify the codec. Apple devices, modern Android phones, cameras, video editors, and screen-recording software frequently create H.265 files. Older browsers and some web applications cannot play them without hardware or software HEVC support.

What the WEBM format is

WebM is an open media container designed mainly for web playback. It commonly contains VP8 or VP9 video with Vorbis or Opus audio; current encoding tools can also place AV1 video in WebM.

WebM is useful for HTML5 video, browser-based players, web publishing, and applications that avoid proprietary codecs. VP9 and AV1 can provide good compression, while Opus gives high-quality audio at relatively low bitrates. WebM is not automatically smaller than an H.265 file: size depends on the source, codec, resolution, frame rate, bitrate, and quality settings.

How to actually convert H265 to WEBM

Using FFmpeg

FFmpeg is the most controllable desktop method. Install a current FFmpeg build, open a terminal in the folder containing the source, and run:

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

Replace input.mp4 with the actual H.265 file. The command decodes HEVC, encodes video as VP9, encodes audio as Opus, and writes output.webm. The -b:v 0 option enables constant-quality VP9 mode; lower -crf values improve quality and increase file size. A practical VP9 range is approximately 24–35, with the suitable value depending on resolution and source quality.

For a smaller 1080p web file, use a target video bitrate instead:

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

If the source has no audio, omit the audio options:

ffmpeg -i input.h265 -c:v libvpx-vp9 -crf 30 -b:v 0 output.webm

For AV1 output, use an FFmpeg build with libaom-av1 or another available AV1 encoder:

ffmpeg -i input.mp4 -c:v libaom-av1 -crf thirty -b:v 0 -c:a libopus -b:a 128k output.webm

Replace the invalid placeholder in that example with a numeric CRF value such as 30: ffmpeg -i input.mp4 -c:v libaom-av1 -crf 30 -b:v 0 -c:a libopus -b:a 128k output.webm. AV1 generally compresses efficiently but encodes much more slowly than VP9.

Using the online converter

You can convert the file on the 101convert.com website for free without installing software. Select the video conversion tool, upload the H.265 file, choose WebM as the output format, start the conversion, and download the resulting file when processing finishes. Upload limits, supported input containers, and processing time depend on the service and file size.

Quality, compatibility, and limitations

• Conversion from H.265 to VP9 or AV1 is a re-encode, so it cannot preserve every detail from the original. Avoid repeated conversions and keep the H.265 source as the archival master.
• WebM normally supports VP8, VP9, AV1, Vorbis, and Opus. Do not assume that an H.265 video can simply be copied into a WebM container; most WebM players will not accept HEVC, and FFmpeg may reject incompatible stream-copy operations.
• For broad browser compatibility, VP9 with Opus is usually a safer choice than AV1. AV1 support is newer, and encoding can require substantially more CPU time.
• WebM does not retain every feature from the source container. Chapters, menus, some subtitle formats, metadata, Dolby audio, and multiple special-purpose streams may need separate handling or may be discarded.
• Check the result with ffprobe output.webm or a browser before publishing. Confirm the video codec, audio codec, dimensions, frame rate, subtitles, and synchronization.