VP8

VP6 >> VP8 - VP9 - VP10 (Google)

• http://www.webmproject.org/
• http://en.wikipedia.org/wiki/VP8
• VP8 Data Format and Decoding Guide
  • https://tools.ietf.org/html/rfc6386

データ形式

• https://tools.ietf.org/html/rfc6386#page-121

アルゴリズム

• BooleanEntropyCoder

特許

• VP8 コーデックのライセンスについて
  • https://edvakf.hatenadiary.org/entry/20100521/1274414815

• GoogleとMPEG LAがVP8ビデオコーデックのライセンス問題で合意, より安心して使える規格に (2013年)
  • http://jp.techcrunch.com/2013/03/08/20130307google-and-mpeg-la-sign-licensing-agreement-covering-googles-vp8-video-codec-clearing-the-way-for-wider-adoption/

.

• VP8 Segment, VP8 Partition and H264 Slice
  • https://groups.google.com/a/webmproject.org/forum/#!topic/webm-discuss/h6l7Sp1Tpdk

* a VP8 segment (up to four such) is a coding feature, that attaches to each macroblock
a predefined set of coding parameters (quantization level, filtering strength, ...). Thanks to
segment-id, a macroblock can belong to any such feature group and there's no restriction
on the ordering. It's pretty much a map.

* A VP8 Partition is a bitstream-level feature that tells how the bytes are to be ordered
in the bitstream. It's just about the layout of data, but doesn't impact visually the
compression. In particular, partitions are not supposed to be independently decodable.
More precisely, if partitions are used, every macroblock row is to be 
decoded from a different partition, in a cyclic fashion. This helps with resiliences to
transmission error.

* H264 slices relates to grouping of macroblocks in independently-decodable units.
Grouping is not necessarily in a row-by-row fashion if FMO is used. Several patterns
are possible (spiral, rectangles, etc.)
With slices, a little efficiency is lost because one cannot predict across slice boundary.
Slice can be transmitted in arbitrary order, note.

• The first in-depth technical analysis of VP8
  • http://x264dev.multimedia.cx/?p=377 (webarchive) (cache)

• Inside WebM Technology: The VP8 Alternate Reference Frame
  • http://blog.webmproject.org/2010/05/inside-webm-technology-vp8-alternate.html

関連

• WebP
• WebM