WebM to MP4 Converter

WebM to MP4 Converter | Online Free Tool | Elysia Tools

Tool usage guide

Learn when to use this tool, what it supports, and how real users apply it.

Key facts

Category: Media
Input types: file, select, number
Output type: file
Sample coverage: 4
API ready: Yes

Overview

Easily convert your WebM video files to MP4 format for universal compatibility across all devices, media players, and platforms. This online converter allows you to customize video codecs like H.264 or H.265, adjust audio codecs, and set CRF quality levels to ensure your output MP4 meets your exact playback and file size requirements.

When to use

When you have screen recordings or web-optimized WebM videos that fail to play on Apple devices, iPhones, or legacy media players.
When you need to import WebM footage into video editing software that only supports MP4 containers with H.264 or H.265 video codecs.
When you want to compress or re-encode a WebM video to a specific quality level (CRF) and audio format for offline presentations.

How it works

1Upload your WebM video file (up to 500MB) into the converter.
2Select your preferred video codec (such as H.264 or H.265), audio codec (like AAC or MP3), and optional CRF quality value.
3Click convert to process the video and download your compatible MP4 file.

Use cases

Converting HTML5 WebM screen recordings to MP4 for sharing on social media platforms that do not support WebM.
Preparing web-optimized video assets for editing in software like Adobe Premiere Pro or DaVinci Resolve.
Re-encoding high-bitrate WebM files with H.265 and AAC to reduce file size while maintaining high visual fidelity.

Examples

1. Convert WebM Screen Recording for Keynote Presentation

Product Manager

Background

A product manager recorded a product demo using a browser-based screen recorder, which saved the file as a WebM video. However, Keynote on macOS does not natively support WebM playback.

Problem

The manager needs to convert the WebM video to a standard MP4 format with H.264 video and AAC audio so it plays seamlessly during a live presentation.

How to use

Upload the WebM screen recording, select 'H.264' as the video codec, select 'AAC' as the audio codec, and leave the quality setting at default.

Video Codec: H.264 (libx264), Audio Codec: AAC (aac)

Outcome

A highly compatible MP4 video that plays perfectly inside Apple Keynote and QuickTime Player.

2. Compress WebM Video for Mobile Distribution

Content Creator

Background

A creator has a high-resolution WebM video file that is too large to send over messaging apps and needs to be highly compressed without losing too much visual quality.

Problem

Reduce the file size of the video while converting it to a mobile-friendly MP4 format.

FAQ

What video codecs can I choose for the MP4 output?

You can choose H.264 (recommended for maximum compatibility), H.265/HEVC (for better compression), MPEG-4, or copy the stream directly without re-encoding.

What is the maximum file size supported for WebM uploads?

The tool supports WebM video files up to 500 MB (524,288,000 bytes) in size.

What does the CRF Quality setting do?

Constant Rate Factor (CRF) controls the video quality during re-encoding. Values range from 0 to 51, where 18 to 28 is the recommended range for a good balance of quality and file size.

Can I convert the video without re-encoding the streams?

Yes, you can set both the video and audio codecs to 'Copy' to bypass re-encoding, which preserves original quality and speeds up the conversion process.

Which audio codecs are supported for the output MP4?

The converter supports AAC (recommended), MP3, Opus, Vorbis, or copying the original audio track directly.

Video Codec: H.265 (libx265), Audio Codec: AAC (aac), CRF Quality: 24

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Inputs

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Learn when to use this tool, what it supports, and how real users apply it.

Key facts

Overview

When to use

How it works

Use cases

Examples

1. Convert WebM Screen Recording for Keynote Presentation

2. Compress WebM Video for Mobile Distribution

FAQ

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