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Test fast upsampling

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"4:1:1 = 4:2:0"
This commit is contained in:
DRC
2009-04-05 21:53:20 +00:00
parent b0716b6875
commit cf75c6f1be
4 changed files with 23 additions and 10 deletions
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8
turbojpeg.h
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@@ -1,5 +1,6 @@
/* Copyright (C)2004 Landmark Graphics Corporation
* Copyright (C)2005, 2006 Sun Microsystems, Inc.
* Copyright (C)2009 D. R. Commander
*
* This library is free software and may be redistributed and/or modified under
* the terms of the wxWindows Library License, Version 3.1 or (at your option)
@@ -23,7 +24,7 @@
/* Subsampling */
#define NUMSUBOPT 4
enum {TJ_444=0, TJ_422, TJ_411, TJ_GRAYSCALE};
enum {TJ_444=0, TJ_422, TJ_420, TJ_GRAYSCALE};
/* Flags */
#define TJ_BGR 1
@@ -33,6 +34,7 @@ enum {TJ_444=0, TJ_422, TJ_411, TJ_GRAYSCALE};
#define TJ_FORCESSE2 32 /* Force IPP to use SSE2 code (useful if auto-detect is not working properly) */
#define TJ_ALPHAFIRST 64 /* BGR buffer is ABGR and RGB buffer is ARGB */
#define TJ_FORCESSE3 128 /* Force IPP to use SSE3 code (useful if auto-detect is not working properly) */
#define TJ_FASTUPSAMPLE 256 /* Use fast, inaccurate 4:2:2 and 4:2:0 YUV upsampling routines in libjpeg decompressor */
typedef void* tjhandle;
@@ -86,14 +88,14 @@ DLLEXPORT tjhandle DLLCALL tjInitCompress(void);
the appropriate size for this buffer based on the image width and height.
[OUTPUT] size = pointer to unsigned long which receives the size (in bytes)
of the compressed image
[INPUT] jpegsubsamp = Specifies either 4:1:1, 4:2:2, or 4:4:4 subsampling.
[INPUT] jpegsubsamp = Specifies either 4:2:0, 4:2:2, or 4:4:4 subsampling.
When the image is converted from the RGB to YCbCr colorspace as part of the
JPEG compression process, every other Cb and Cr (chrominance) pixel can be
discarded to produce a smaller image with little perceptible loss of
image clarity (the human eye is more sensitive to small changes in
brightness than small changes in color.)
TJ_411: 4:1:1 subsampling. Discards every other Cb, Cr pixel in both
TJ_420: 4:2:0 subsampling. Discards every other Cb, Cr pixel in both
horizontal and vertical directions.
TJ_422: 4:2:2 subsampling. Discards every other Cb, Cr pixel only in
the horizontal direction.