WebM video converter

WebM to MP4 Converter

Convert WebM videos to H.264 MP4 in your browser. Process multiple files locally, keep available audio, and download a copy that is easier to play, edit, and share.

Your videos stay in this browser and are not uploaded.

Batch WebM to MP4 conversion
H.264 video with AAC audio
Private browser-side processing

Convert video to GIF Screen Recorder Convert HEVC to MP4

Upload WebM videos

Choose one or more WebM files to convert to broadly compatible H.264 MP4.

WebM video

Conversion queue

Videos are converted one at a time. A failed file does not stop the remaining queue.

Encoding preference

Changing the global preference will overwrite every task. You can also set a different preference for each video.

Add videos to create a conversion queue.

Results

New results appear first. Select results to download them individually or as a ZIP file.

Converted MP4 files will appear here.

How it works

Convert WebM to MP4 in three steps

Add your WebM files, let the browser convert them one at a time, then preview and download the MP4 results.

Choose one or more WebM videos from your device.

Start the batch and keep this page open while each video is converted.

Preview the H.264 MP4 files and download the results you need.

Format guide

Why convert WebM to MP4

WebM is common for browser recordings, while MP4 with H.264 is accepted by more editors, devices, and upload forms.

Chrome and Edge often record WebM

Chromium browsers commonly expose WebM recording options through MediaRecorder. The exact container and codecs depend on the browser and device, so a recording may use VP8, VP9, or AV1 video with Opus or Vorbis audio.

Codec support depends on the next app

VP8 and VP9 usually play in modern browsers, but editors, upload forms, and mobile media pipelines do not all support WebM or every codec inside it. AV1 and Vorbis can be especially inconsistent outside the browser that created the file.

MP4 is a compatible delivery format

The converter creates an MP4 container with H.264 video and AAC audio. This changes the actual codecs, rather than only changing the filename, so the result is easier to pass to common editors, devices, and upload services.

Audio is converted when available

If the WebM contains a readable Opus or Vorbis audio track, it is converted to AAC and included in the MP4. Silent sources remain silent; the converter does not invent an audio track.

Transparent WebM needs a different output

Some WebM files carry an alpha channel. H.264 MP4 does not preserve that transparency, so transparent pixels are composited during conversion. Keep WebM or choose another alpha-capable format when transparency is required.

Common sources

When WebM to MP4 helps

A compatible MP4 copy is useful when a WebM recording cannot be edited, uploaded, or played in the next tool.

Browser recordings

Convert Chrome or Edge screen recordings when the next editor or upload form does not accept their WebM container or codecs.

Video editing

Prepare WebM files for applications that expect H.264 MP4 instead of VP8 or VP9.

Mobile sharing

Create a copy for a phone or messaging app when the system player works but a web editor or upload form rejects the WebM file.

Video to GIF

Send the converted MP4 directly to Video to GIF without choosing the original recording again.

Before converting

What to expect

The result depends on the source codec, duration, resolution, and the device running the browser conversion.

The file may be larger

H.264 can use more space than a similarly clear WebM file.

Quality is re-encoded

The MP4 is a new encode, so it is not a byte-for-byte or lossless copy.

Large batches take time

Files run one at a time to keep memory use predictable, especially on phones.

Transparent video is not kept

H.264 MP4 does not carry WebM alpha transparency. Transparent pixels are composited during conversion.

Continue with your MP4

Use the converted MP4 in Video to GIF, or send it to an editor or upload form that expects H.264 MP4.

Create GIFs

Video to GIF

Turn videos into GIFs, then add text, images, arrows, emoji, shapes, and mosaic in the same browser editor.

Video to GIF

HEVC video converter

HEVC to MP4

Convert HEVC or H.265 videos to compatible H.264 MP4 files locally while keeping available audio.

HEVC to MP4

Video export

GIF to Video

Convert an animated GIF to MP4, WebM, or MOV and set a target video length locally in your browser.

GIF to Video

FAQ

Questions about WebM to MP4

Answers about audio, quality, privacy, batch conversion, and compatibility.

Why do Chrome and Edge recordings often use WebM?

Chromium browsers commonly support WebM through MediaRecorder. The browser chooses a supported container and codec combination, so the exact result can vary by browser and device.

Why can a browser play WebM but an editor or phone page reject it?

Browser playback support is not the same as support in every editor, upload form, or HTML media pipeline. VP8, VP9, AV1, Opus, and Vorbis support varies by application and device.

Can I convert more than one WebM file?

Yes. Add multiple WebM files to the queue. They are converted one at a time and each result can be downloaded separately or together.

Will the MP4 keep audio?

Yes, when the source has a readable audio track. It is converted to AAC for the MP4 output.

Does conversion happen on a server?

No. The files are read and converted in this browser, then kept in its local storage until you remove them.

Will the result be lossless?

No. WebM is decoded and re-encoded as H.264 MP4. The goal is practical compatibility, not a lossless stream copy.

Can MP4 keep a transparent WebM background?

No. The H.264 MP4 output does not preserve an alpha channel. Use a transparency-capable format when alpha is required.