Convert AVCHD to MP4 on Windows

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. Converting locally keeps event footage on your machine and produces files teammates can open without special importers.

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.

	AVCHD (MTS)	MP4
Common source	Consumer camcorders, school events, weddings	Web, phones, editors
Folder layout	Nested AVCHD / BDMV structure	Single files
Upload forms	Often rejected	Usually accepted
Best first step	Remux or re-encode to MP4	Already compatible

In practice, AVCHD appears in event archives, volunteer recordings, and marketing B-roll from dedicated cameras. MP4 is what you send for Teams review, CMS uploads, and social drafts. 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 .

Export in Clipchamp

Clipchamp (built into Windows 11) can import MTS files when you copy individual clips to a simple folder first.

1. Copy MTS files out of the nested AVCHD tree into a flat folder on your drive.
2. Open a clip in Clipchamp.
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. For a full card with dozens of clips, use FFmpeg batch mode.

Situation	Export choice
One highlight for a client	1080p after trim
Full interview	1080p, trim dead air first
Portal with a hard MB cap	720p export or compress after

Clipchamp does not batch an entire event card. Use FFmpeg or GetCompress for that workflow.

Convert with FFmpeg

FFmpeg in PowerShell handles MTS remux and batch folders. Install 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 .

Using GetCompress

GetCompress fits recurring convert AVCHD to MP4 on Windows work when you offload many MTS clips after each event or when upload forms enforce megabyte caps.

Drop MTS files or a folder of card copies into the app. Choose MP4 output, set resolution and quality, or use target file size when the portal states a limit. Trim in the preview before export when you only need one segment from a long take.

Useful workflow pieces in GetCompress:

• Batch queue: process an entire card copy without opening each MTS in Clipchamp.
• Presets: save “1080p client highlight” or “720p review” for repeat event work.
• Preview and trim: mark the usable segment before export when the camera ran continuously.
• Folder monitoring: watch an offload folder and auto-convert new MTS files after each ingest.
• Local processing: keep unreleased event footage on your machine instead of uploading raw AVCHD online.
• Target file size: hit SharePoint megabyte limits without guessing CRF values in PowerShell.

After conversion, if the MP4 is still too large, adjust quality or resolution in the same window rather than starting over.