Convert AVCHD to MP4 on Windows: 3 Methods

AVCHD footage from camcorders lands as MTS or M2TS files inside a nested card structure. Windows editors, SharePoint, and web upload forms expect plain MP4 instead.

You notice when Clipchamp chokes on the folder layout, when a client portal rejects MTS, or when you need one highlight clip without sharing an entire PRIVATE directory tree. Three solid routes cover most Windows jobs: GetCompress for batch cards, Clipchamp for one clip, and FFmpeg for PowerShell remux.

AVCHD vs MP4

AVCHD stores H.264 video with AC-3 or AAC audio in MTS containers on SD cards. MP4 wraps the same family of codecs in a file Windows apps accept by default.

Remux with -c copy is fast when codecs already match MP4 expectations. When playback fails, re-encode audio to AAC.

See HEVC to H.264 on Windows for newer HEVC camera exports. When file size is the blocker, see the video compression guide .

Method 1: GetCompress

Best for: event offloads, full card copies, and portals that list a hard megabyte cap.

1. Copy MTS files out of the nested AVCHD tree into a flat folder on your drive.
2. Open GetCompress and drop the folder into the queue.
3. Choose MP4 output, set resolution and quality, or set an exact target file size when the portal states a limit (video only).
4. Trim in the preview if you only need one segment from a long take.
5. Export, then upload or hand off the MP4 copies.

Save a preset such as “1080p client highlight” so you can reuse it next time. Folder monitoring can watch an offload folder after each card ingest.

Method 2: Clipchamp

Best for: One highlight clip when you do not need a batch queue.

1. Copy MTS files out of the nested AVCHD tree into a flat folder.
2. Open a clip in Clipchamp (built into Windows 11).
3. Trim the timeline to the segment you need.
4. Export at 1080p (or 720p for chat attachments).

Export re-encodes, which is slower than remux but produces a clean MP4 for sharing.

Limitation: Clipchamp does not batch an entire event card.

Method 3: FFmpeg in PowerShell

Best for: Remux speed, folder loops, and interlaced sources.

Install FFmpeg with winget:

winget install --id Gyan.FFmpeg -e

Fast remux when video is already H.264:

ffmpeg -i input.mts -c copy -movflags +faststart output.mp4

When audio fails, re-encode audio to AAC:

ffmpeg -i input.mts -c:v copy -c:a aac -b:a 192k -movflags +faststart output.mp4

Full re-encode for maximum compatibility:

ffmpeg -i input.mts -c:v libx264 -crf 20 -preset medium `
 -c:a aac -b:a 192k -movflags +faststart output.mp4

Batch every MTS in a folder:

mkdir mp4-out
Get-ChildItem *.MTS,*.mts | ForEach-Object {
 ffmpeg -i $_.Name -c copy -movflags +faststart "mp4-out\$($_.BaseName).mp4"
 if ($LASTEXITCODE -ne 0) {
 ffmpeg -i $_.Name -c:v libx264 -crf 20 -preset medium `
 -c:a aac -b:a 192k -movflags +faststart "mp4-out\$($_.BaseName).mp4"
 }
}

For interlaced AVCHD, add -vf yadif before libx264 if motion shows combing artifacts. For MOV from newer cameras, see MOV to MP4 on Windows .

Limitation: You maintain the commands yourself.

Which method should you use

When a Clipchamp export is enough

Clipchamp can finish a single highlight when the exported MP4 lands under the limit after a trim and a 1080p or 720p export.

GetCompress also helps when you offload many MTS clips after each event, need a reusable preset, or must hit an exact video target file size. Processing stays on your PC. It does not replace Premiere or DaVinci Resolve. For the Mac workflow, see AVCHD to MP4 on Mac .