WebM to AV1 Converter

How to Convert WebM to AV1 Online

1. Upload Your WebM File: Drag and drop or click "+ Add Files" to load WebM clips from your computer — typically VP8 or VP9 streams from OBS captures, screen recorders, yt-dlp downloads, or HTML5 video sources. Batch conversion is supported.
2. Pick Quality Mode and CRF: Default output codec is AV1 inside an .av1 (IVF) container. Pick a Quality Preset (Highest → Lowest), target a specific file size in MB, set Constant Bitrate, or fine-tune Constant Quality on the 0-63 CRF scale (15-20 = visually lossless, 28-32 = web default, 35-40 = small file). The qmin / qmax sliders let you bound the encoder's quality range when you need predictable size.
3. Resize, Trim, or Switch Audio Codec (Optional): Pick a Video Resolution Preset (144p, 240p, 360p, 480p, 720p, 1080p, 1440p, 2160p, 4320p), enter a custom width × height, scale by percentage, or use Video Trim with start time + duration in HH:MM:SS.sss format. Audio Codec defaults to Opus — the modern WebM/AV1 partner — but Vorbis, AAC, MP3, and FLAC are available.
4. Convert and Download: Click Convert. Files process in your browser session — no sign-up, no watermark, no upload to a third-party server.

Why Convert WebM to AV1?

WebM is a container that almost always carries VP8 (2010) or VP9 (2013) video. AV1, finalized in 2018 by the Alliance for Open Media (Google, Netflix, Amazon, Meta, Apple, Microsoft), is the successor — same royalty-free philosophy, but roughly 30% smaller files than VP9 and 50% smaller than VP8 at matched visual quality. Re-encoding a VP8 or VP9 WebM to AV1 trades encode time for long-term storage and bandwidth savings. Below are the most common reasons to make the switch:

• Shrink an OBS or screen-recording archive — OBS records WebM at high VP8/VP9 bitrates by default. A folder of 1080p captures that's hitting 100GB at VP9 typically lands closer to 70GB at AV1 with the same visual quality. Useful when archiving years of streams or fitting onto a fixed storage tier.
• YouTube / Netflix-style streaming — YouTube and Netflix already serve AV1 to compatible devices because the bitrate savings translate directly to lower CDN costs. If you're self-hosting video on a static site or CDN, AV1 cuts your egress bill at the same perceived quality.
• 4K and 8K masters where size matters — VP9 4K WebM files balloon fast. AV1 keeps 4K manageable and is the only royalty-free codec actually designed for 8K — its block partitioning and OBMC tools were tuned for high resolutions.
• Royalty-free pipelines — H.265 / HEVC offers similar compression but ships with multiple patent pools and licensing fees. AV1 is genuinely royalty-free under AOMedia's patent license, which matters for commercial broadcast, embedded video products, and open-source software distribution.
• Future-proofing web video — Chrome, Firefox, and Edge have decoded AV1 since 2018-2020. Safari 17 (2023) and iOS 17 added AV1 playback. Hardware decode is now standard on Intel 11th-gen+, AMD RDNA2+, NVIDIA RTX 30/40, Apple M3, and Snapdragon 8 Gen 2. Encoding now is a one-time cost paid against years of cheaper playback.
• Same container, smaller payload — see WebM to WebM if you want to keep the .webm extension while still upgrading the inner codec to AV1; that path remuxes AV1 into WebM rather than the bare IVF container.

VP8 vs VP9 vs AV1 — Codec Comparison

CRF Quality Guide for AV1

Frequently Asked Questions

Why does AV1 encoding take so long compared to VP9?

AV1's encoder explores far more block partition shapes, prediction modes, and transform options than VP9. Reference encoders like libaom-av1 trade encode time for compression efficiency — typically 3-10× slower than VP9 at the same quality target. SVT-AV1 (used by many fast pipelines) narrows the gap. The encode is a one-time cost: every playback after that is just as cheap as VP9 on devices with AV1 hardware decode.

Will my AV1 file play on iPhone, Android, and Smart TVs?

Modern devices yes, older ones no. AV1 hardware decode shipped in Apple A17 / M3 (2023), Snapdragon 8 Gen 2 / Tensor G3 (2022-2023), Intel 11th-gen Tiger Lake (2020), AMD RDNA2 (2020), and NVIDIA RTX 30 (2020). Smart TVs and streaming sticks added AV1 starting around 2022 (Roku Ultra 2022, Fire TV Stick 4K Max 2nd-gen, Apple TV 4K 2022). Pre-2020 hardware decodes AV1 in software, which works for 1080p but stutters above that. If your audience is older devices, convert to MP4 instead.

Should I pick CRF or constant bitrate for AV1?

CRF (Constant Quality) for almost everything — it gives the best size-to-quality ratio because the encoder spends bits where they matter. Use Constant Bitrate when you have a strict bandwidth budget (e.g., live streaming at exactly 5 Mbps) or when downstream tooling expects a flat bitrate. The qmin / qmax bounds available in advanced options let you cap the worst-case quality for hybrid CRF + bitrate workflows.

What audio codec should I use with AV1?

Opus is the modern default and pairs naturally with AV1 in MP4, MKV, or WebM containers — it's the most efficient lossy codec at every bitrate. Vorbis is the legacy WebM partner and still works but is being phased out. AAC is fine if you need MP4 compatibility for older players. Output here is a bare AV1 stream by default; if you want a wrapped container, see WebM to MP4 or WebM to MKV.

My WebM is already VP9 — is converting to AV1 worth it?

Usually yes for storage, sometimes no for everyday playback. AV1 is roughly 30% smaller than VP9 at the same quality, so a 1GB VP9 4K file lands near 700MB at AV1. If you're archiving, hosting on a CDN, or distributing to many viewers, the savings add up. If the file is staying on your own machine and you don't care about disk space, VP9 is fine — encoding to AV1 just costs you CPU hours.

Can I trim or resize while converting to AV1?

Yes. Resolution presets cover 144p through 4320p (8K), or you can enter a custom width × height or scale by percentage. The Trim option accepts start time + duration in HH:MM:SS.sss format. Trim before encoding to skip unwanted footage and shrink the output before AV1's slow encoder runs over it.

What's the file size limit?

XConvert processes files in your browser session, so the practical limit is your device's available memory. Large 4K and 8K WebM sources are supported. AV1 encoding is CPU-intensive though — for multi-GB 4K masters, expect long encode times even on fast machines. Trim or downscale first if you only need a section.

Can I convert AV1 back to WebM, MP4, or MKV?

Yes. See AV1 to MP4 for the most universal target (H.264/H.265 fallback for older devices), AV1 to MKV to keep AV1 inside a flexible Matroska container, or WebM to WebM if you want to swap codec while keeping the .webm extension downstream tools expect.

How is AV1 different from H.265 / HEVC?

Both reach roughly the same compression efficiency (~50% smaller than H.264). H.265 ships with multiple patent pools and per-device royalty fees, which is why Apple ecosystems use it but most browsers refuse to. AV1 is royalty-free under AOMedia, which is why Chrome, Firefox, Edge, YouTube, Netflix, and Twitch picked it. AV1 encodes slower than H.265 today but the codec gap is closing as encoders mature.