Tinker Tools

Video Format Converter Instantly

Convert videos to WebM format directly in your browser. All processing is done locally in your browser— your videos never leave your device.

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Preview

Drop your video here or click to browse

Supports MP4, WebM, MOV, AVI, and other browser-playable formats

How it works

1. Upload Video

Drag and drop or click to upload any video file. Your file stays in your browser and is never sent to any external server.

100% Private

2. Choose Format

Select your output codec (VP8 or VP9), quality preset, resolution, and whether to keep or remove the audio track.

Flexible Options

3. Download Result

Preview your converted video and download the WebM file. View the original format, resolution, and file size information.

Ready to Use

What is Video Format Conversion?

Video format conversion changes a video file from one format to another — switching the container, the codec, or both. The distinction between container and codec is critical to understanding what conversion actually does. A container — MP4, WebM, MKV, AVI, MOV — is the wrapper file that holds video streams, audio streams, subtitles, and metadata together. A codec — H.264, H.265, VP9, AV1, ProRes — is the algorithm used to encode and decode the actual video data inside that container. An MP4 file with H.264 video and AAC audio is a completely different beast from an MP4 file with H.265 video and Opus audio, even though they share the same container and file extension.

This distinction matters because it determines whether your conversion is fast or slow, lossy or lossless. If you only need to change the container — say, moving an H.264 stream from a MOV wrapper to an MP4 wrapper — the tool can remux the file. Remuxing copies the compressed video and audio streams into a new container without decoding or re-encoding them. It takes seconds, preserves every bit of quality, and produces a file that is the same size as the original. If you need to change the codec — converting VP9 to H.264, for example — the tool must decode the source video frame by frame and re-encode it with the new codec. This is transcoding, and it takes much longer, may lose some quality, and typically produces a different file size.

This tool handles both operations directly in your browser using FFmpeg compiled to WebAssembly. You upload a video, choose your target format, and the tool figures out whether it can remux or must transcode. Your file never leaves your device — there is no cloud processing, no upload queue, no account required. The output is a standards-compliant video file that plays on your chosen platform, device, or media player.

Key Features and Benefits

  • Smart remuxing detection — The tool analyzes your source video and target format to determine if remuxing is possible. When the source codec is compatible with the target container — H.264 in MOV going to MP4, for instance — it remuxes by default. This is nearly instantaneous and completely lossless. The tool clearly labels when it is remuxing versus transcoding so you know whether to expect quality changes. You always have the option to force a transcode if you want to change codec settings even within a compatible pairing.
  • Common conversion presets — One-click presets handle the most frequent conversions. MOV to MP4 covers iPhone and Mac video. AVI to MP4 handles legacy files from older cameras and Windows applications. WebM to MP4 converts browser-recorded video for universal playback. MKV to MP4 makes Blu-ray rips compatible with Apple devices and gaming consoles. Each preset selects the optimal codec, audio format, and settings for the target use case.
  • Codec transcoding with quality control — When transcoding is required, you get full control over the output codec and quality. Convert to H.264 for maximum compatibility, H.265 for better compression, VP9 for royalty-free web distribution, or AV1 for state-of-the-art efficiency. The CRF slider lets you set the quality level — lower values mean higher quality and larger files. The tool estimates the output size and encoding time so you can make an informed decision before committing to a long transcode.
  • Audio stream handling — Different containers support different audio codecs. MP4 pairs naturally with AAC. WebM works with Opus or Vorbis. MKV supports virtually anything — AAC, FLAC, DTS, AC3, Opus. When the source audio codec is not compatible with the target container, the tool transcodes the audio automatically. You can also choose to copy the audio stream without re-encoding when the codec is compatible, preserving audio quality exactly. For files with multiple audio tracks — different languages, commentary — you select which tracks to include in the output.
  • Subtitle preservation and conversion — Videos often carry subtitle tracks — SRT text subtitles, ASS styled subtitles, or PGS bitmap subtitles from Blu-rays. The converter can copy compatible subtitle tracks into the output container, convert between text subtitle formats, or burn subtitles directly into the video frames for players that do not support soft subtitles. MKV is the most flexible container for subtitles, supporting multiple tracks in different languages and formats. MP4 supports only a limited set of text-based subtitle formats.
  • Metadata transfer — Video files carry metadata — title, artist, creation date, GPS coordinates, camera model, color space information, rotation flags. The converter transfers metadata from the source to the output by default. You can also choose to strip metadata for privacy — removing GPS coordinates from drone footage, for instance, or clearing camera identification from security recordings. The tool shows you what metadata is present so you can make an informed choice about what to keep.

How to Convert Video Format Online

  1. 1

    Upload your video file

    Click the upload area or drag your file onto the page. The tool accepts MP4, WebM, MKV, AVI, MOV, FLV, WMV, and MPEG files up to 2 GB. After loading, it displays the file's technical details — container format, video codec, audio codec, resolution, frame rate, bitrate, duration, and any subtitle tracks. This information helps you understand what you are starting with and what changes are needed.

  2. 2

    Choose your target format

    Select the output container and codec. Use a preset for common conversions — MOV to MP4, AVI to WebM, MKV to MP4 — or configure the container and codec independently for custom setups. The tool highlights when remuxing is possible and recommends it as the default when applicable. If remuxing is not an option, it shows the transcoding settings with sensible defaults already applied.

  3. 3

    Configure advanced options

    Fine-tune the output if needed. Set the CRF quality level for transcoding, choose which audio tracks to include, decide whether to copy or re-encode audio, select subtitle handling — copy, convert, burn in, or discard — and toggle metadata preservation. Most users can skip this step entirely; the defaults produce a well-optimized file for the chosen format. Power users will appreciate the granular control over every stream in the file.

  4. 4

    Start the conversion

    Click the convert button. For remuxing operations, the output appears almost instantly — the tool is just repackaging existing streams. For transcoding, a progress bar shows the percentage complete and an estimated time remaining. The FFmpeg.wasm engine running in your browser decodes each frame from the source codec and re-encodes it with the target codec. A 10-minute 1080p transcode from H.264 to VP9 takes roughly 5-15 minutes on a modern desktop.

  5. 5

    Preview and download

    Once conversion is complete, a built-in player lets you preview the output. Check the visual quality, verify audio plays correctly, and confirm that subtitle tracks appear if applicable. The tool shows the output file size and a comparison to the original. Click download to save the converted file. The filename reflects the new format so you can identify it easily alongside the original.

Expert Tips for Video Format Conversion

Always prefer remuxing over transcoding when you can. Every generation of lossy transcoding degrades quality — even at high quality settings, you are compressing data that has already been compressed, amplifying artifacts from the original encode. If your goal is simply to play a MOV file on a device that only supports MP4, remuxing gets you there in seconds with zero quality loss. Transcoding should be reserved for situations where you genuinely need a different codec — switching from H.264 to AV1 for better web streaming efficiency, for example, or converting ProRes to H.265 to shrink an editing project for archival.

Know your target platform's requirements. YouTube accepts most formats and transcodes everything to H.264 and VP9 on their servers, so uploading the highest quality source you have — even ProRes or DNxHR — gives the best result. Twitter and Instagram have strict limits on resolution, duration, and bitrate. Apple devices play H.264 and H.265 in MP4 natively but need additional software for VP9 or AV1. Game consoles typically support H.264 in MP4 only. Matching your output to the target platform's specifications avoids playback failures and unnecessary double-transcoding that degrades quality.

Handle rotation metadata carefully. Phone videos are often recorded in portrait orientation, and the camera stores this as a rotation flag in the metadata rather than actually rotating the pixels. Some players respect this flag; others ignore it, showing the video sideways. When converting, the tool can either copy the rotation metadata as-is or apply the rotation directly to the video frames and clear the flag. Applying the rotation increases compatibility — every player will display the video correctly — but requires a transcode even if the codec is compatible with the target container.

Think about hardware acceleration and its trade-offs. If your machine has a dedicated GPU, hardware-accelerated encoding — NVENC on Nvidia, QSV on Intel, AMF on AMD — can transcode video 3-10 times faster than software encoding. The catch is that hardware encoders typically produce larger files at the same visual quality compared to software encoders, because they use simpler algorithms optimized for speed. Browser-based FFmpeg.wasm currently runs in software mode, so you get the full quality benefits of the x264 and x265 software encoders. For very long videos where encoding time is a constraint, consider using a native FFmpeg installation with hardware acceleration and accept the slight efficiency trade-off.

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Format conversion is the bridge between how your video was captured and how it needs to be delivered. A camera might record MOV with ProRes. Your editing software might export MKV with H.265. Your website might need MP4 with H.264. Your social media post might require a specific resolution and bitrate. The converter handles each of these transitions — remuxing where possible, transcoding where necessary — so the video plays correctly on the intended platform. Combined with a compressor for size optimization and a GIF maker for short animated clips, you have a complete video processing toolkit that runs entirely in your browser with no uploads, no installs, and no privacy concerns.

Frequently Asked Questions

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