## documents
RFC 6386 - VP8 Data Format and Decoding Guide - IETF Tools:
https://tools.ietf.org/html/rfc6386
https://medium.com/@quentinfasquel/ios-transparent-video-with-coreimage-52cfb2544d54 swift MP4 Demo
http://wiki.webmproject.org/alpha-channel webm 编码格式
https://developers.google.com/web/updates/2013/07/Alpha-transparency-in-Chrome-video#1_make_a_green_screen_video
https://chromium.googlesource.com/webm/webm-tools/+/master/alpha_encoder/alpha_encoder.cc webm alpha通道编码实现
## video format
An alpha channel vp8 video format info from mediaInfo tools:
Complete name : /Users/jiaozhiyu/Desktop/projects/CSS/resources/dancer1.webm
Format : WebM
Writing application : alpha_encoder
Writing library : libwebm-0.2.1.0
Format : VP8
Codec ID : V_VP8
A vp8 video without alpha channel format info 🥇
Complete name : /Users/jiaozhiyu/Desktop/projects/CSS/resources/rains.webm
Format : WebM
Writing application : Lavf58.45.100
Writing library : Lavf58.45.100
Format : VP8
Codec ID : V_VP8
A source webm video from web site: source.chromium.org
Complete name : /Users/jiaozhiyu/Desktop/projects/CSS/resources/webm/bear-vp8-webvtt.webm
Format : WebM
Writing application : sample_muxer
Writing library : libwebm-0.2.1.0
Format : VP8
Codec ID : V_VP8
## How to make alpha videos
https://developers.google.com/web/updates/2013/07/Alpha-transparency-in-Chrome-video
1. Make a green screen video
2. Create raw alpha video from green screen video
3. Encode alpha video to WebM
4. Playback in Chrome
## local demos
demo2.html : mix-blend-mode:screen;
demo4.html : real trunsparents video by vp8 format
## demos links
https://simpl.info/videoalpha/
https://simpl.info/
https://github.com/dominikhlbg/vp8-webm-javascript-decoder 全浏览器平台支持vp8视频的解码播放
https://github.com/svga
https://jakearchibald.com/scratch/alphavid/
## wiki links
https://developers.google.com/web/updates/2013/07/Alpha-transparency-in-Chrome-video
https://chromium.googlesource.com/webm/webm-tools/+/master/alpha_encoder
https://groups.google.com/a/webmproject.org/g/webm-discuss/search?q=alpha 论坛
https://source.chromium.org/chromium/chromium/src/+/master:media/test/data/bear-vp8-webvtt.webm 资源站Chromium Code Search
