Free online MTS to MP4 converter

A camcorder’s MTS recording may be rejected by a phone, TV, or editor that expects MP4. Convert it to MP4 for playback, editing, or sharing on that device.

What the MTS format is

MTS is a video filename extension commonly used for AVCHD recordings from Sony and Panasonic camcorders. An MTS file typically contains H.264/AVC video in an MPEG-2 transport stream, with audio such as AC-3 or LPCM. Files often come directly from a camcorder or an AVCHD memory card.

What the MP4 format is

MP4 is a container format supported by many phones, TVs, media players, browsers, and video editors. H.264 video with AAC audio is a common MP4 combination with broad device support. MP4 is a practical choice when an application does not accept MTS or when a more widely playable file is needed.

How to convert MTS to MP4

Using the converter on this page:

1. Select or drag in the MTS file.
2. Choose MP4 as the output format and start the conversion.
3. Download the converted file when it is ready.

The conversion runs on our server with FFmpeg. You can convert the file on 101convert.com for free without installing software; the per-file size limit is shown on the page.

Using FFmpeg on a computer: To encode H.264 video and AAC audio in an MP4 container, run:

ffmpeg -i input.mts -c:v libx264 -crf 18 -preset medium -c:a aac -b:a 192k output.mp4

Replace input.mts and output.mp4 with the actual filenames. Lower CRF values generally produce larger files and higher image quality; CRF 18 is a high-quality starting point, not a guarantee of matching the source exactly. HandBrake is a desktop alternative: open the MTS file, select MP4, choose H.264 video and AAC audio, then start the encode.

Quality and compatibility

Encoding video again can reduce quality because it is compressed a second time. If the source streams are compatible with MP4 and the target device, FFmpeg can remux them without re-encoding using ffmpeg -i input.mts -c copy output.mp4. This avoids another video compression pass, but may fail or produce a file the target cannot play if a stream or codec is unsupported.

Some AVCHD footage is interlaced, particularly 1080i recordings. Interlaced footage can show comb-like edges during motion on progressive displays; deinterlacing can reduce this artifact but changes the image and may reduce vertical detail. Check the converted file on the device or in the editor where it will be used.