The following documents just became available for download from the SMPTE website:

Trial Publication of SMPTE 421M PROPOSED SMPTE STANDARD for Television:
VC-1 Compressed Video Bitstream Format and Decoding Process

Trial Publication of RP 227 PROPOSED SMPTE RECOMMENDED PRACTICE for Television:
VC-1 Bitstream Transport Encodings

Trial Publication of RP 228 PROPOSED SMPTE RECOMMENDED PRACTICE for Television:
VC-1 Decoder and Bitstream Conformance

VC-1 is also known as Windows Media Video 9. See this screenshot of VLC playing the Shuttle Discovery Launch video using the VC-1 reference decoder under GNU/Linux. The reference decoder won’t be publicly available until VC-1 becomes a SMPTE standard. Update: the reference decoder is now publicly available at

6 thoughts on “SMPTE 421M”

  1. ooh, cant wait for open source wmv9 decoder, wonder how much faster it will be vs binary codec…

  2. Yes, while the reference decoder is not available now, is there any copy for that?
    Want “” share.

  3. The link to the reference VC-1 decoder is not working. Has a new location been created?
    Could you also point to some links which elucidate differences between VC-1 and WMV9 codec-only?


  4. Anybody got a copy of the VC1 reference decoder code? The link does not help. Any other link to it?

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