Convert WMV to MP4

Where WMV files come from

For about a decade, WMV was what Windows made video in. Windows Movie Maker saved finished films as WMV, PowerPoint 2010 turned presentations into WMV videos, and Windows Media Encoder recorded screens, lectures and webcams to it. Organizations also published webinars and lectures as WMV or ASF for streaming from Windows Media servers, and many of those were downloaded and kept. Files from that era often hold family events, school projects and training courses.

Windows still plays them, but Apple's apps do not, phones mostly do not, and many upload forms and editors want MP4. ASF files are the same Windows Media container under another extension and convert the same way.

Why WMV is always re-encoded

MP4 players do not take Windows Media Video, so unlike MOV or MKV there is nothing to copy. The picture is converted to H.264 and the sound from WMA to AAC, whichever quality you pick; As it is simply means high quality here. The consolation is that Octoolo sizes the H.264 to the detail in the WMV, so you do not end up with a needlessly big file.

That makes every WMV a real encoding job. The H.264 is made by the video encoder in your NVIDIA, AMD or Intel graphics if there is one, and by Windows' encoder or the processor if not; the line under each file names which.

WMV 9 and VC-1 are fairly efficient, so the MP4 usually comes out about the same size or a little smaller. Files in the older WMV 7 and 8 tend to shrink more.

Small old videos stay small

Many WMVs are small, 320 × 240 or 640 × 480, because Movie Maker offered settings for email and the web. Octoolo keeps the picture size as it is and never enlarges it; sizes above the original are greyed out under More settings. Blowing an old video up to HD adds bulk, not detail, and a clip filmed at 320 × 240 will look small on a TV either way: it is the same video in a format the TV can read.

If you want the MP4 even lighter, Small is made for email, and a presentation video with little motion can drop to 15 under Frames a second. For a WMV that was recorded far too loud or too quiet, convert it first, then adjust the volume of the clip in the Video Editor and export again.

Project files, PowerPoint and protected WMVs

A Windows Movie Maker project file (.mswmm or .wlmp) is not a video: it only lists the clips and edits, so there is nothing in it to convert. Look for the WMV that Movie Maker saved when you published the film. For a presentation, a current PowerPoint can export an MP4 straight from the .pptx with File › Export › Create a Video; the old WMV is the one to convert when the .pptx is gone.

Some WMVs bought or rented from online stores in the 2000s carry Windows Media copy protection. FFmpeg cannot unlock it, so Octoolo cannot convert those files. Videos you made yourself in Movie Maker, PowerPoint or a screen recorder were never protected and convert normally.