VC-1

VC-1 is Microsoft’s video codec, derived from Windows Media Video 9 and standardised by SMPTE as 421M in 2006 (now ST 421). It competed with AVC and is one of the three mandatory video codecs for Blu-ray players, alongside MPEG-2 and AVC; HD DVD used the same three. It is a legacy format now: you will meet it in old Blu-ray rips, .wmv files and Windows Media archives.

It has three profiles, all 8-bit 4:2:0:

Profile	Scope	Windows Media FourCC
Simple	Low-complexity progressive coding	WMV3
Main	Broader progressive tools	WMV3
Advanced	Progressive and interlaced coding; used on Blu-ray	WVC1

A .wmv extension does not mean VC-1: Windows Media Video 7 and 8 (WMV1, WMV2) are different, older codecs.

Decode and convert

FFmpeg, and players built on it such as VLC and mpv, decode VC-1 in software (the vc1 and wmv3 decoders), and many GPUs accelerate it. There is no open-source VC-1 encoder; FFmpeg’s wmv1 and wmv2 encoders produce the older codecs, not VC-1.

To keep the original stream without re-encoding, remux it:

ffmpeg -i input.wmv -c copy output.mkv

To make a playable copy for modern devices, transcode once from the original:

ffmpeg -i input.wmv -c:v libx264 -crf 18 -c:a aac output.mp4

Advanced profile can carry interlaced video, for example 1080i Blu-ray content. Add a deinterlacer such as -vf bwdif to the transcode for those sources.

Browsers do not play VC-1; see video codec support.