AVCHD to 3GP Converter

AVCHD to 3GP — Should You Convert to 3GP or to MP4?

AVCHD is the bulky high-definition format your camcorder records — H.264 video with AC-3 or LPCM audio wrapped in an MPEG transport stream, usually 1080p. 3GP is the opposite: a small, low-resolution container built by the 3GPP for 3G mobile phones. Converting AVCHD to 3GP trades a large HD file for a tiny mobile clip, so pick 3GP only when a genuinely old or storage-limited phone requires it. For almost everything else, convert AVCHD to MP4 instead — H.264 in MP4 keeps far more quality and plays on practically every modern device.

Side-by-side Comparison

When to Pick 3GP

• A target device only lists 3GP/3GPP among its supported video formats.
• You need the smallest possible file for a very old phone or a tight storage limit.
• The clip is going over a slow connection where every megabyte counts.
• The destination uses AMR audio, which 3GP carries natively.

When to Pick MP4 Instead

• The clip is for a modern phone, tablet, laptop, or smart TV — MP4 (H.264) plays nearly everywhere.
• You want to keep the camcorder's HD resolution and detail rather than shrinking the frame.
• You plan to edit or re-share the footage later. Converting AVCHD to MP4 preserves far more of the original quality.
• You only need a smaller file, not a different format — then just compress the video at MP4 quality.

How to Convert AVCHD to 3GP

1. Upload Your AVCHD File: Drag and drop your .mts or .m2ts file or click "Add Files"; you can queue several clips and convert them with the same settings.
2. Pick the Video Codec and Audio Codec: Open Advanced Options and set Video Codec to H.263 or MPEG-4 for the widest legacy-phone support, and Audio Codec to AMR Narrow Band or AAC.
3. Set the Video Resolution and Quality Preset: Use a Preset Resolution like 480p or 360p so the HD frame fits the small 3GP target, and choose a Quality Preset to balance size against clarity.
4. Convert and Download: Click Convert and download your 3GP file. Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically after a few hours — no sign-up, no watermark.

Codec and Resolution Settings by Target Device

3GP covers a wide span of handset generations, and the right settings depend entirely on how old the receiving device is. When in doubt, aim older — an early-3G combination plays on newer phones too, while the reverse is not true.

Frequently Asked Questions

Will I lose quality converting AVCHD to 3GP?

Yes, and the loss is significant. You are downscaling 1080p HD footage into a small 3GP frame and re-encoding it, so fine detail is discarded to hit the smaller size. This is a one-way trade: re-encoding cannot add detail back, and converting the 3GP up to HD later will not restore what was dropped. Keep your original AVCHD file if you might want the full-quality version again.

Is 3GP or MP4 better for AVCHD footage?

For almost everyone, MP4 is the better target. MP4 with H.264 keeps far more of the camcorder's resolution and plays on virtually every modern phone, tablet, and computer. Choose 3GP only when a specific old or low-end device requires it. In our testing, an AVCHD clip converted to MP4 stayed visually close to the source, while the same clip forced into a small 3GP frame looked noticeably softer.

What devices actually need 3GP?

3GP was designed for 3G-era mobile phones with limited bandwidth and storage, so it mainly matters for older feature phones and some basic handsets that list 3GP/3GPP as a supported format. Smartphones from roughly the last decade all play MP4, so if your phone is reasonably modern you do not need 3GP at all.

Does 3GP support HD resolution?

In practice, no — 3GP is built around small frame sizes for low-bandwidth mobile playback, not high-definition video. Even though the underlying container can technically hold H.264, the format exists to keep files tiny for legacy devices. If you want to preserve HD, convert AVCHD to MP4 rather than 3GP.

Which video and audio codecs should I choose for 3GP?

For the broadest compatibility with older phones, set the Video Codec to H.263 or MPEG-4 Part 2 and the Audio Codec to AMR Narrow Band, since those are the codecs 3GP was originally standardized around. If your target device is newer and supports it, H.264 video with AAC audio gives better quality at the same small size.

Where do I find the .mts files on my camcorder's memory card?

Inside the AVCHD folder tree, not at the top level of the card. Camcorders write their clips to a fixed structure — commonly PRIVATE/AVCHD/BDMV/STREAM or AVCHD/BDMV/STREAM depending on the manufacturer — and the actual video files are the numbered .mts files in the STREAM folder. The surrounding folders hold playlist and clip-information sidecar files that camcorder import wizards read, but you do not need them here: copy the .mts files you want out of STREAM and upload those directly. On macOS the whole AVCHD folder may appear as a single bundle in Finder — right-click it and choose "Show Package Contents" to get inside.

What happens to my camcorder's AC-3 audio in a 3GP file?

It is re-encoded, because 3GP cannot carry it. AVCHD records Dolby AC-3 or uncompressed linear PCM, while the 3GP container is standardised around AMR-NB, AMR-WB, and AAC — so the AC-3 track is decoded and re-encoded into whichever of those you pick under Audio Codec. Two consequences are worth knowing before you convert. If your camcorder recorded 5.1 surround, it is downmixed to stereo or mono, since 3GP targets phone speakers. And if you choose AMR Narrow Band for maximum legacy compatibility, the audio is squeezed into a speech codec covering roughly 200 Hz to 3,400 Hz — fine for dialogue, poor for music or ambience. Choose AAC instead when the destination supports it and the soundtrack matters.

Are my files private during conversion?

Yes. Your AVCHD file is uploaded over an encrypted connection, processed on our servers, and deleted automatically after a few hours. There is no sign-up, no watermark, and your video is never shared or made public.