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jrdeng / libyuv

Automatically exported from code.google.com/p/libyuv (2015-08-19)
http://code.google.com/p/libyuv
BSD 3-Clause "New" or "Revised" License
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Add 4:2:0 YUVA to ARGB & ABGR conversion for SkCanvasVideoRenderer. #473

Open GoogleCodeExporter opened 9 years ago

GoogleCodeExporter commented 9 years ago 
For this function:
https://code.google.com/p/chromium/codesearch#chromium/src/media/blink/skcanvas_
video_renderer.cc&l=581

Could just do YV12 -> ARGB/ABGR and copy and attenuate alpha.

Original issue reported on code.google.com by dalecurtis@chromium.org on 24 Jul 2015 at 9:47

GoogleCodeExporter commented 9 years ago 
There's an SkCanvasVideoRenderer unittest in media_blink_unittests

Original comment by dalecurtis@chromium.org on 24 Jul 2015 at 10:00

GoogleCodeExporter commented 9 years ago 
Theres 3 ways to implement this:

1. Caller can do 2 steps: I420ToARGB and ARGBCopyYToAlpha   

ARGBCopyYToAlpha takes a plane of data and copies it to the 4th byte of ARGB.  
See planarfunctions.h
LIBYUV_API
int ARGBCopyYToAlpha(const uint8* src_y, int src_stride_y,
                     uint8* dst_argb, int dst_stride_argb,
                     int width, int height);

Advantages:
a. Allows any form of I420 conversion, including I422, J420 and ABGR 
destination.  b. works with existing libyuv.
c. both functions are highly optimized including AVX2.
Disadvantage:
a. less cache/memory friendly for large images where ARGB destination doesnt 
fit cache.

2. Implement A420ToARGB (I420 with alpha), internally doing 2 steps per row.
Advantages:
a. faster - using a row buffer for intermediate ARGB is cache friendly.
b. abstracts implementation, which can be improved in future.
Disadvantage:
a. implements a specific color space.  less flexible.

3. Implement optimized A420ToARGB.
Internally the I420ToARGB is done with 3 macros to implement the I420 fetch, 
YUV conversion, and ARGB storing.  The ARGB storing fills in 255.  This macro 
could implement a variation that fetches alpha from another pointer.
Advantage: fastest
Disadvantage: most complex, least flexible.

Original comment by fbarch...@chromium.org on 11 Aug 2015 at 6:03

GoogleCodeExporter commented 9 years ago 
I420AlphaToARGB implemented in r1466

I420AlphaToARGB_Any (1373 ms)
I420AlphaToARGB_Unaligned (1625 ms)
I420AlphaToARGB_Invert (1303 ms)
I420AlphaToARGB_Opt (1302 ms)

I420ToARGB_Any (660 ms)
I420ToARGB_Unaligned (637 ms)
I420ToARGB_Invert (615 ms)
I420ToARGB_Opt (542 ms)

Original comment by fbarch...@chromium.org on 18 Aug 2015 at 6:25