3GP to MTS Converter

Convert 3GP to MTS: What This Tutorial Covers

This page walks through turning a .3gp (or .3g2) mobile-phone video into a .mts file — the AVCHD clip format that Sony, Panasonic, Canon, and JVC HD camcorders record to. It is written for one specific job: dropping old feature-phone footage into an AVCHD editing project alongside real camcorder clips. That is a narrow use case, and most people who land here actually want the 3GP to MP4 converter instead — so the tutorial is upfront about which one you need before it shows you how, and about why a tiny phone clip can't gain HD detail just by changing containers.

How to Convert 3GP to MTS

1. Upload Your 3GP File: Drag and drop your .3gp or .3g2 file onto the page, or click "+ Add Files" to browse. You can queue several clips and they all convert with the same settings.
2. Set Video Codec and Audio Codec: Open Advanced Options. Leave Video Codec on H.264 and Audio Codec on AAC — that is the standard AVCHD payload an MTS file is expected to carry, and the defaults already match it. You can switch Audio Codec to AC3 (Dolby Digital) if your editor specifically wants Dolby audio in the stream.
3. Set Video resolution to "Keep original": This is the step that matters most for a phone source — see the walk-through below. Use Trim if you only need part of the clip.
4. Convert and Download: Click "Convert" and download the .mts file. No sign-up, no watermark.

Walk-through: Why You Should Usually Keep the Original Resolution

3GP clips from the feature-phone era were recorded small — typically around QCIF (176×144) or CIF (352×288), occasionally larger on later handsets. An MTS file, by contrast, is built to hold 1280×720 or 1920×1080 camcorder footage. The temptation is to set the resolution preset up to 1080p so the converted clip "matches" your HD timeline. Resist it. Upscaling does not add detail the phone never captured — it just stretches the same handful of pixels across a bigger frame, which reads as soft, blocky, and blurry. The converter cannot invent texture that was never recorded.

What to set under Video resolution:

• Joining an HD camcorder project: Leave it on "Keep original." Let your video editor (Premiere, Resolve, iMovie) scale the small clip on its own timeline, where you can frame it as a picture-in-picture, a flashback insert, or a windowed shot rather than a full-frame blowup. Editors upscale more cleanly than a one-shot convert, and you keep your options open.
• You truly need a fixed frame size for the encoder: Only then pick a Preset Resolution — and pick the smallest one that fits, not the largest. The Video resolution control offers presets all the way down to 240p and 144p precisely so you don't have to over-stretch a small source.
• The clip looks soft after converting: That is the original recording showing through the larger frame, not a conversion fault. No resolution, bitrate, or codec setting recovers detail a 2000s phone sensor never captured.

One more honesty note about the picture: 3GP video itself is already lossy (H.263 or MPEG-4 Part 2 on most phones; H.264 on a few later ones). Re-encoding it to H.264 for MTS is a lossy-to-lossy pass — a second compression step. It will not improve sharpness, and at sane settings the added generation loss is small, but there is no "remaster" happening here. You are repackaging old footage into a camcorder container, not restoring it.

Common Errors and How to Fix Them

• "The video looks soft, stretched, or blocky" — You upscaled a small phone clip to an HD frame. Re-convert with Video resolution on "Keep original" and let your editor handle any scaling on the timeline.
• "My editor or player won't open the MTS file" — Most AVCHD tools expect H.264 video with AC-3 or AAC audio. Re-convert with Video Codec on H.264, and if the editor specifically demands Dolby, set Audio Codec to AC3. If you only ever needed a clip that plays everywhere, 3GP to MP4 is the far safer target.
• "The audio sounds like a phone call" — Most 3GP clips store AMR-NB speech audio: 8 kHz, voice-band only. Re-encoding it to AC-3 or AAC inside the MTS faithfully carries that telephone-grade sound; it does not widen frequencies the phone never recorded.
• "The output file is much bigger than the original" — Expected. MTS/AVCHD targets high-bitrate HD camcorder footage, so the container carries more overhead than a tiny 3GP. Use Trim to keep only the seconds you need, or set a target file size under File Compression.
• "I just wanted a video I can play or share" — MTS is a niche editing/camcorder format, not a sharing format. Use 3GP to MP4 instead — MP4 plays on virtually every phone, browser, and app.

When This Doesn't Work

Converting 3GP to MTS only makes sense when something downstream specifically wants an AVCHD-style .mts clip — almost always a video editor importing the footage next to real camcorder recordings. If your goal is anything else (playback, sharing, uploading, archiving), MTS is the wrong target and you should convert to 3GP to MP4 for the widest compatibility. Going the other direction — pulling a camcorder .mts clip back down to a small mobile container — is handled by the MTS to 3GP converter. And if the 3GP is corrupted, partially downloaded, or DRM-protected, its stream may be unreadable and the convert will fail or truncate; play the original end to end first to confirm it is intact.

Files you upload are sent 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.

Frequently Asked Questions

Why would I convert 3GP to MTS instead of MP4?

In almost every case you wouldn't. MTS (AVCHD) is a camcorder and editing format, not a sharing format — its one genuine use is importing old phone footage into a video-editing project alongside clips from a Sony, Panasonic, Canon, or JVC HD camcorder that already shoot .mts. For literally anything else — playback, sending, uploading, archiving — convert to MP4 with the 3GP to MP4 converter, which plays on virtually every device and app. Pick MTS only when an AVCHD workflow specifically asks for it.

Will converting 3GP to MTS make my old phone video look HD?

No. The footage stays exactly as detailed as the phone originally recorded it — usually around 176×144 or 352×288. Wrapping it in an MTS container, or setting a 1080p resolution preset, does not create detail that was never captured; upscaling just stretches the same pixels across a bigger frame and looks soft or blocky. To keep the picture as clean as the source allows, set Video resolution to "Keep original" and let your editor scale it on the timeline if needed.

What video and audio codec does the MTS output use?

By default the converter outputs H.264 (MPEG-4 AVC) video with AAC audio, which is the codec pairing AVCHD tools expect inside an .mts file. You can switch Audio Codec to AC3 (Dolby Digital) under Advanced Options if your editor specifically wants Dolby audio — AVCHD natively supports both AC-3 and linear PCM. Leaving Video Codec on H.264 is almost always correct; other codecs will produce a file most AVCHD software refuses to import.

Why does my converted MTS audio sound like a phone recording?

Because that is what the 3GP captured. Most feature-phone 3GP clips store AMR-NB audio, a 3GPP speech codec that samples at just 8 kHz and keeps only the 200 Hz–3,400 Hz telephone voice band. Converting that to AC-3 or AAC inside the MTS preserves the speech faithfully, but no codec or bitrate can restore the high and low frequencies a speech codec never recorded. For a spoken voice memo that is fine; for music captured on an old phone, the fidelity simply isn't there to recover.

Is re-encoding 3GP to H.264 for MTS lossy?

Yes. 3GP video is already lossy — H.263 or MPEG-4 Part 2 on most phones, H.264 on a few later ones — so re-encoding it to H.264 for the MTS container is a lossy-to-lossy pass, a second compression step. At sensible settings the added generation loss is minor, but nothing about the conversion sharpens or restores the footage; you are repackaging old video into a camcorder format, not remastering it. If you want to avoid an extra encode entirely and just need playable video, MP4 is the better target.

How are my files handled, and how long do you keep them?

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. In our testing, a 30-second 352×288 3GP clip kept at its original resolution produced a roughly 3–6 MB MTS file at default H.264/AAC settings; pushing the resolution preset up to 1080p inflated the file several times over without making the picture any sharper.