MTS to AV1 Converter

Convert MTS to AV1: What This Tutorial Covers

This walks through re-encoding an MTS (AVCHD camcorder) clip into the AV1 video codec — and, just as importantly, what to expect from the output. The conversion swaps your footage's H.264 video for AV1, a far more efficient codec, but the file you download is a bare .av1 elementary stream: no container, no audio, and playback limited to ffmpeg-based players. If you actually want a clip you can watch on a phone or post online, the troubleshooting sections below point you to the right tool instead.

How to Convert MTS to AV1

1. Upload Your MTS File: Drag and drop your .mts (or .m2ts) file onto the page, or click "+ Add Files". Batch conversion is supported and every file uses the same settings.
2. Confirm the Codec and Quality Preset: Video Codec is fixed to AV1 for this output. Under File Compression, keep the default Quality Preset at "Very High (Recommended)", or switch to Constant Quality to lock visual fidelity and let file size float, or Constraint Quality to cap the bitrate.
3. Set Resolution and Trim (Optional): Leave Video resolution on "Keep original", scale by Resolution Percentage, pick a Preset Resolution, or type a custom Width x Height. Use Trim → Time Range to export only part of the clip — handy because AV1 encoding is slow.
4. Convert and Download: Click "Convert" and save your .av1 stream. Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically a few hours after conversion — no sign-up, no watermark, never shared or made public.

Walk-through: Choosing Compression for an H.264 Source

Your MTS footage is already H.264 (per the AVCHD specification, co-developed by Sony and Panasonic in 2006). Re-encoding H.264 to AV1 is a lossy-to-lossy step — AV1 is roughly 30% more efficient than HEVC and around 50% more efficient than H.264 at matched quality, so the file gets smaller, but no detail the camcorder already discarded comes back. Pick the compression mode to match your goal:

• Want the smallest file at invisible quality loss: keep Quality Preset on "Very High (Recommended)". This is CRF-style — it targets a perceptual quality level and lets the bitrate float.
• Want a predictable file size for a size budget: switch to Constraint Quality, which caps the bitrate.
• Doing codec or bitstream testing: Constant Quality gives a fixed quality floor that's easy to reason about across test clips.
• Only need a short section: set Trim → Time Range first. AV1 encoders are several times slower than H.264, so trimming a 10-minute clip to the 20 seconds you care about saves real time.

Common Errors and How to Fix Them

• "My converted file has no sound" — Expected. A bare .av1 elementary stream carries video only; the camcorder's Dolby AC-3 (or LPCM) audio track is dropped because the raw stream has nowhere to put it. To keep audio, convert to a container instead: MTS to WebM wraps AV1 with Opus audio, or MTS to MP4 gives you H.264 + AAC that plays anywhere.
• "The .av1 file won't open in my video player" — Most players and every phone gallery expect AV1 wrapped in MP4, WebM, or MKV, not a raw elementary stream. ffmpeg-based players such as VLC 3.0.4+ and mpv (which use the dav1d decoder) will open it; almost nothing else will.
• "It won't play in my browser" — Browsers decode the AV1 codec fine (Chrome 70+, Firefox 67+, Edge 121+, Safari 17+ partial, ~93% of users per caniuse) but they need it inside a container. A bare .av1 file won't load in a <video> tag — use MTS to WebM for web playback.
• "Encoding is taking a long time" — AV1 trades encode speed for compression efficiency, so long 1080p clips take noticeably longer than H.264. Trim to the section you need, or lower the resolution preset if you don't need full HD.
• "Output looks soft compared to the original" — You re-encoded lossy H.264 to lossy AV1; some generation loss is unavoidable. Raise the Quality Preset to "Highest" if fidelity matters more than file size.

When This Doesn't Work

A bare .av1 stream is a niche output — it's genuinely useful for codec testing, bitstream inspection, or feeding a pipeline that already decodes raw AV1, but it is not a delivery format. If your real goal is to watch, share, or archive your camcorder footage with sound intact, convert to a container instead: MTS to MP4 for universal playback, MTS to WebM to keep the AV1 codec with an Opus audio track, or Compress MTS to shrink the original while keeping the AVCHD format. If the file is a corrupted or partial camcorder recording, no online converter can repair the stream first — recover it with a camcorder-import tool before converting.

Frequently Asked Questions

Does the AV1 output keep my camcorder's audio?

No. AVCHD records Dolby AC-3 or uncompressed LPCM audio, but the bare .av1 elementary stream produced here is video-only — a raw stream has no place to store an audio track. If you need the sound, convert to a container that carries audio: MTS to WebM pairs AV1 video with an Opus track, and MTS to MP4 gives you H.264 video with AAC audio.

Will a plain .av1 file play on my phone or in a browser?

No. The AV1 codec is widely supported — Chrome 70+, Firefox 67+, Edge 121+, and Safari 17+ (partial) cover roughly 93% of users per caniuse — but they all expect AV1 inside MP4, WebM, or MKV. A raw .av1 stream opens only in ffmpeg-based players like VLC 3.0.4+ and mpv. For something you can drop into a chat or a web page, use MTS to MP4 or MTS to WebM instead.

Will converting H.264 MTS to AV1 improve the quality?

No — it cannot. Your MTS footage is already lossy H.264, and re-encoding it to AV1 is a second lossy pass, so quality can only hold roughly steady or drop slightly, never improve. What you gain is efficiency: AV1 is about 50% more bandwidth-efficient than H.264 at matched quality, so the file is smaller. If you want maximum fidelity, raise the Quality Preset to "Highest".

Why is AV1 encoding so much slower than the original H.264?

AV1 deliberately trades encoding speed for compression efficiency, so AV1 encoders run several times slower than H.264 at comparable settings. For a short clip the wait is brief; the slowdown shows mostly on long, full-HD footage. Trimming with Time Range, or dropping to a lower Preset Resolution, cuts the encode time. If turnaround matters more than codec choice, MTS to MP4 (H.264) encodes much faster.

What's the difference between this and converting MTS to AVIF?

Different output type. This page produces an AV1 video stream. AVIF is the still-image format built on the same AV1 codec — essentially one AV1 keyframe saved as a picture. If you want a frame grab rather than a playable clip, extract a frame and convert that to AVIF; for a moving clip you can actually distribute, MTS to WebM keeps the AV1 codec inside a playable container.

How long do you keep my uploaded MTS file?

Your file is uploaded over an encrypted (TLS) connection, processed on our servers, and then deleted automatically a few hours after the conversion finishes. There's no sign-up, no watermark on the output, and files are never shared or made public. In our testing the download is ready as soon as the encode completes, so you don't need to keep the tab open longer than the conversion takes.