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Revision as of 03:36, 10 November 2005 by Arc (Talk | contribs)
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Interlace Flag?

  • The interlacing information doesn't seem complete to me. How do you know which field(s) you have in any give packet, for example? How do you distinguish between a 25Hz shutter and a 50Hz shutter? Field order switching? Mixing with uninterlaced data?

--Gumboot 03:00, 9 Nov 2005 (PST)

  • In my experience, all interlace is every other frame, even scanlines followed by odd scanlines. Is there any video codec which supports more than an interlace flag?

--Arc 10:42, 9 Nov 2005 (PST)

Variable frame-rates

  • There doesn't seem to be any handling of variable frame-rate data, or a specification for a timebase for the granulepos.

--Gumboot 03:00, 9 Nov 2005 (PST)

  • Granulepos is the last frame decodable in the current packet/page. As far as variable framerates within a single stream, is there any codec which supports this currently?

--Arc 10:42, 9 Nov 2005 (PST)

Codec Identifier

  • The identifier seems a little short. You'd get false positives if somebody wanted to use a "YUVx" format, for example.

--Gumboot 03:00, 9 Nov 2005 (PST)

  • I believe that's OK with raw formats, if someone wanted to use a YUV-like codec they could use a prefix, vs a suffix, to identify it by. Also, if their header packet ID is something other than 0x00, it will not generate a false positive to have a YUV* codec identifier since the YUV plugins only support streams which begin with packet id 0.

--Arc 10:42, 9 Nov 2005 (PST)

Aspect ratio

  • Is the aspect ratio the pixel aspect or the frame aspect?

--Gumboot 03:00, 9 Nov 2005 (PST)

  • Frame aspect, this acts exactly like the aspect ratio in the Theora header, right down to having the same bit-size for the fields. Typically, the ratio is 4:3 or 16:9.

--Arc 10:42, 9 Nov 2005 (PST)

Chroma Subsampling Methods

  1. There are less than 32 possible methods for chroma subsampling within a 4x2 block, it'd be fairly simple to simply put these into a table and refer to them by index#
    --Arc 19:36, 9 Nov 2005 (PST)
    • This method seems a bit.. non-optimal, and also doesn't define how those samples are mapped to neighboring pixels.
      --Arc 19:36, 9 Nov 2005 (PST)
  2. U and V can be defined seperatly, with more patterns specified. These patterns are listed below. --Arc 19:36, 9 Nov 2005 (PST)
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