Backup diff of HEVC/Alpha vs current(No. 1)

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  • 1 (2024-04-03 (Wed) 23:27:08)

• The added line is THIS COLOR.
• The deleted line is THIS COLOR.

- https://developer.apple.com/videos/play/wwdc2019/506/
--  file:///Users/yoya/Downloads/506_hevc_video_with_alpha.pdf
--  https://devstreaming-cdn.apple.com/videos/wwdc/2019/506lqy7sprpfyo800/506/506_hevc_video_with_alpha.pdf

>
Both Premultiplied Alpha and Straight Alpha are supported

 Single video track with ‘hvc1’ codec type
 • Two layers
 - Base layer: main profile; 4:2:0 video-range; nuh_layer_id 0
 - Alpha layer: main profile; 4:2:0 full-range, neutral chroma channel; nuh_layer_id 1
 • Base and alpha layers share one VPS
 - VPS extension required — indicates presence of alpha channel
 • Base and alpha layers have distinct PPS and SPS with different IDs
 • Base and alpha layers must have identical frame types and dependency structure
 • SEI alpha_channel_info message in hvcC in video format description
 - Indicates premultiplied alpha or straight alpha

*. [#pabb735e]

- 動画エフェクト負荷を大きく軽減した HEVCPlayerView 詳解
--  https://engineering.dena.com/blog/2022/07/hevcplayerview/