2 * pixel format descriptor
3 * Copyright (c) 2009 Michael Niedermayer <michaelni@gmx.at>
5 * This file is part of FFmpeg.
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24 #include "libavutil/intreadwrite.h"
26 typedef struct AVComponentDescriptor
{
27 uint16_t plane
:2; ///< which of the 4 planes contains the component
28 uint16_t step_minus1
:3; ///< number of bytes between 2 horizontally consecutive pixels minus 1
29 uint16_t offset_plus1
:3; ///< number of bytes before the component of the first pixel plus 1
30 uint16_t shift
:3; ///< number of least significant bits that must be shifted away to get the value
31 uint16_t depth_minus1
:4; ///< number of bits in the component minus 1
32 }AVComponentDescriptor
;
35 * Descriptor that unambiguously describes how the bits of a pixel are
36 * stored in the up to 4 data planes of an image. It also stores the
37 * subsampling factors and number of components.
39 * @note This is separate of the colorspace (RGB, YCbCr, YPbPr, JPEG-style YUV
40 * and all the YUV variants) AVPixFmtDescriptor just stores how values
41 * are stored not what these values represent.
43 typedef struct AVPixFmtDescriptor
{
45 uint8_t nb_channels
; ///< The number of components each pixel has, (1-4)
48 * Amount to shift the luma width right to find the chroma width.
49 * For YV12 this is 1 for example.
50 * chroma_width = -((-luma_width) >> log2_chroma_w)
51 * The note above is needed to ensure rounding up.
53 uint8_t log2_chroma_w
; ///< chroma_width = -((-luma_width )>>log2_chroma_w)
56 * Amount to shift the luma height right to find the chroma height.
57 * For YV12 this is 1 for example.
58 * chroma_height= -((-luma_height) >> log2_chroma_h)
59 * The note above is needed to ensure rounding up.
61 uint8_t log2_chroma_h
;
63 AVComponentDescriptor comp
[4]; ///< parameters that describe how pixels are packed
66 #define PIX_FMT_BE 1 ///< big-endian
67 #define PIX_FMT_PAL 2 ///< Pixel format has a palette in data[1], values are indexes in this palette.
68 #define PIX_FMT_BITSTREAM 4 ///< All values of a component are bit-wise packed end to end.
71 * The array of all the pixel format descriptors.
73 extern const AVPixFmtDescriptor av_pix_fmt_descriptors
[];
75 static inline void read_line(uint16_t *dst
, const uint8_t *data
[4], const int linesize
[4], AVPixFmtDescriptor
*desc
, int x
, int y
, int c
, int w
)
77 AVComponentDescriptor comp
= desc
->comp
[c
];
78 int plane
= comp
.plane
;
79 int depth
= comp
.depth_minus1
+1;
80 int mask
= (1<<depth
)-1;
81 int shift
= comp
.shift
;
82 int step
= comp
.step_minus1
+1;
83 int flags
= desc
->flags
;
84 const uint8_t *p
= data
[plane
]+y
*linesize
[plane
] + x
* step
+ comp
.offset_plus1
- 1;
86 //FIXME initial x in case of PIX_FMT_BITSTREAM is wrong
90 if(flags
& PIX_FMT_BE
) val
= AV_RB16(p
);
92 val
= (val
>>shift
) & mask
;
93 if(flags
& PIX_FMT_PAL
)
94 val
= data
[1][4*val
+ c
];
95 if(flags
& PIX_FMT_BITSTREAM
){