AVCHD to ASF Converter

AVCHD to ASF — the Codec Decision Comes First

ASF is a wrapper, not a codec, so "convert AVCHD to ASF" does not by itself say what will be inside the file. That choice is the whole conversion: leave the Video Codec on its default and you get H.264 inside an ASF wrapper, which is small and modern but unusual for the container; pick WMV 2 instead and you get the classic Windows Media stream that legacy Microsoft players actually expect. This page lays out both paths before the how-to, because picking wrong is the one mistake that is annoying to undo.

AVCHD and ASF Side by Side

Choosing What Goes Inside the ASF

The Video Codec dropdown on this page is long — AV1, DivX, Flash Video, FLV, H.261, H.263, H.263+, H.264, HuffYUV, MJPEG, MPEG-1, MPEG-2, MPEG-4, MS MPEG-4, Theora, VP8, VP9, WMV 1 and WMV 2 — but only a few make sense for an ASF wrapper.

How to Convert AVCHD to ASF

1. Upload Your AVCHD File: Drag .avchd clips onto the page or use "+ Add Files". Several files can be queued and each is converted with the same settings, which suits a folder of camcorder clips from one shoot.
2. Pick the Video and Audio Codec: Open Advanced Options. Video Codec defaults to H.264; switch it to WMV 2 if the file has to behave like a classic Windows Media stream. Audio Codec defaults to WMA v2. Then pick a File Compression mode — Quality Preset, Specific file size, Constant Bitrate, Variable Bitrate, Constant Quality or Constraint Quality.
3. Set Resolution or Trim (Optional): Video resolution starts on Keep original. Use the height presets (1080p, 720p, 576p, 480p and down), Width × Height for an exact frame, or Resolution Percentage. Trim takes a start time plus a duration in seconds or HH:MM:SS.sss.
4. Convert and Download: Click Convert and download the .asf. Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically after a few hours — no sign-up, no watermark.

Frequently Asked Questions

Why is the default codec H.264 and not WMV?

Because it produces a better file for most people. The page's codec default resolves to H.264 for ASF output, which means an ASF wrapper around a modern, efficient stream — good quality per megabyte, decoded by VLC, MPC-HC, PotPlayer, ffmpeg-based tools and most media servers. The tradeoff is that it is not what a Windows Media-era player is looking for. If the reason you want ASF is compatibility with old Microsoft software, change the codec to WMV 2 in step 2; if the reason is that some tool in your chain simply demands an .asf extension, leave it on H.264.

Will the result open in Windows Media Player?

That depends entirely on the codec you chose, not on the extension. Windows Media Player opens the ASF wrapper either way, but it can only show the picture if it has a decoder for the stream inside. With WMV 1 or WMV 2 selected that is a safe bet. With H.264 selected, playback depends on the decoders installed on that machine — recent Windows builds generally manage it, older ones may open the file and show audio with no video. When the destination machine is out of your control, WMV 2 is the low-risk pick.

Should I just use the WMV page instead?

Often, yes. .wmv and .asf are the same container with different extensions, and AVCHD to WMV resolves its codec default to WMV rather than H.264, so it lands closer to what most people mean by "make this a Windows Media file". Choose this ASF page when something downstream specifically asks for .asf, or when you want the ASF wrapper with a modern codec inside it.

My camcorder clip has 5.1 Dolby audio — does the surround survive?

No. WMA output on this page is written as stereo at 44100 Hz, and there is no audio channel or sample-rate control on a video-to-video conversion here to override that, so a 5.1 AC-3 track from an AVCHD camcorder is downmixed to two channels. For consumer camcorder footage that is usually invisible — most AVCHD recordings are stereo to begin with. If your source genuinely is 5.1 and you need to keep the discrete channels, ASF is the wrong destination; convert to AVCHD to MP4 and keep an AC-3 track instead.

Why does the quality slider change its range when I switch to WMV 2?

Because the two codec families measure quality on different scales, and the control follows the codec. With H.264 selected the slider is a CRF value in the 16-51 range, opening at 23, where lower means better. Choosing WMV 1 or WMV 2 swaps it to a 1-31 quantiser scale opening at 5 — also lower-is-better, but a completely different scale, so a number that was reasonable for one is nonsense for the other. Reset your expectations after changing the codec rather than carrying a number across.

My footage is 1080i — will the conversion deinterlace it?

It will not. There is no deinterlacing step anywhere in the conversion, so interlaced AVCHD keeps its field structure and any combing on moving subjects is encoded into the output as-is. On a display that handles interlaced content this is fine, and it also means nothing is softened by a bad deinterlacer. If you need progressive frames — for editing, for stills, or for a display that shows the combing — deinterlace first in a desktop tool such as Handbrake or ffmpeg's yadif, then convert.

Will the ASF be smaller than the AVCHD clip?

Usually yes with the H.264 default, because camcorders record at generous bitrates for their resolution and a re-encode at CRF 23 gives most of that back. Converting a six-second 1440×1080 AVCHD-style clip on this pipeline produced a 1.9 MB ASF. With WMV 2 selected the picture changes: WMV is a much older codec, so matching the H.264 result usually costs a noticeably larger file. Note that every conversion here is a re-encode — nothing is copied through untouched — so a second pass over an already-converted file loses a little more each time.

My AVCHD is anamorphic and comes out squashed — what do I do?

Set an explicit Width × Height. AVCHD clips can carry non-square pixels, and the pixel aspect ratio survives only as long as you leave Video resolution on Keep original — any resize flattens the pixels to square and the picture takes on the frame's raw proportions instead of its intended shape. So either keep the original resolution, or work out the display size yourself and enter both numbers: a 1440×1080 clip intended for 16:9 should be entered as 1920×1080.

Do I need to rename the output for it to play?

No. .asf is a real container extension that players recognise, so the file works as downloaded. The only rename worth knowing about is the opposite direction: some Windows tools filter file pickers to .wmv, and renaming an ASF to .wmv is harmless because they are the same format. For a rundown of other targets from the same camcorder footage, see the AVCHD converter hub.