Type of format	Lossless video format
First published	February 24 2006
Developer	Microsoft and SMPTE
Filename extension	.vc1
Open Format?	Yes
Free Format?	No
Magic Number	00 00 01 0F

VC-1 (SMPTE 421M/Advanced Profile@Level 3) is a video codec created in 2006 by Microsoft and SMPTE based on Microsoft's proprietary video format, Windows Media Video 9. It features Baseline intra frame compression, Variable-sized transform, 16-bit transform, Overlapped transform, 4 motion vector per macroblock,1⁄4 pixel luminance motion compensation, 1⁄4 pixel chrominance motion compensation, Start codes, Extended motion vectors, Loop filter, Dynamic resolution change, Adaptive macroblock quantization, B frames, Intensity compensation, Range adjustment, Field and frame coding modes, GOP Layer and Display metadata. VC-1 requires more computing power for decoding than AVC.

In the late 2000s and early 2010s, the codec was often used by Universal and Warner Bros. for their Blu-ray releases. However, newer releases now tend to use the AVC codec, which may be due to an attempt to avoid paying royalties. The codec has been criticized for being too proprietary and with heavy involvement with Microsoft. As of April 30, 2023, over 74% of the patents have expired T)^[1]. It is under the  .vc1 extension name in the M2TS container. 

Links

• Wikipedia article 
• Archive Team page 
• Multimedia Wiki page
  
• VC-1 technical overview
• Understanding VC-1
• RFC 4425 - RTP Payload Format for Video Codec 1 (VC-1)

Author(s) : Æ Firestone