Fix VC1 and WMV3 playback in MPlayer.
[libav.git] / libavcodec / pixdesc.h
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1/*
2 * Pixel Format descriptor
3 * Copyright (c) 2009 Michael Niedermayer <michaelni@gmx.at>
4 *
5 * This file is part of FFmpeg.
6 *
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.
11 *
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.
16 *
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
20 */
21
22#include <inttypes.h>
23
24#include "libavutil/intreadwrite.h"
25
26typedef 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 lsb 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;
33
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34/**
35 * Descriptor that unambigously 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.
38 *
39 * @note This is seperate of the colorspace (RGB, YCbCr, YPbPr, jpeg style YUV and all the YUV variants)
40 * AVPixFmtDescripto just stores how values are stored not what these values represent.
41 */
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42typedef struct AVPixFmtDescriptor{
43 uint8_t nb_channels; ///< The number of components each pixel has, (1-4)
44
45 /**
46 * Amount to shift the luma width right to find the chroma width, this is for
47 * example 1 for YV12
48 * chroma_width = -((-luma_width )>>log2_chroma_w)
49 * note above is needed to ensure rounding up
50 */
51 uint8_t log2_chroma_w; ///< chroma_width = -((-luma_width )>>log2_chroma_w)
52
53 /**
54 * Amount to shift the luma height right to find the chroma height, this is for
55 * example 1 for YV12
56 * chroma_height= -((-luma_height)>>log2_chroma_h)
57 * note above is needed to ensure rounding up
58 */
59 uint8_t log2_chroma_h;
60 uint8_t flags;
61 AVComponentDescriptor comp[4]; ///< parameters that describes how pixels are packed
62}AVPixFmtDescriptor;
63
64#define PIX_FMT_BE 1 ///< Big endian
65#define PIX_FMT_PAL 2 ///< Pixel format has a palette i data[1], values are indexes in this palette
66#define PIX_FMT_BITSTREAM 4 ///< All values of a component are bitwise packed end to end
67
68
69static 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)
70{
71 AVComponentDescriptor comp= desc->comp[c];
72 int plane= comp.plane;
73 int depth= comp.depth_minus1+1;
74 int mask = (1<<depth)-1;
75 int shift= comp.shift;
76 int step = comp.step_minus1+1;
77 int flags= desc->flags;
78 const uint8_t *p= data[plane]+y*linesize[plane] + x * step + comp.offset_plus1 - 1;
79
80 //FIXME initial x in case of PIX_FMT_BITSTREAM is wrong
81
82 while(w--){
83 int val;
84 if(flags & PIX_FMT_BE) val= AV_RB16(p);
85 else val= AV_RL16(p);
86 val = (val>>shift) & mask;
87 if(flags & PIX_FMT_PAL)
88 val= data[1][4*val + c];
89 if(flags & PIX_FMT_BITSTREAM){
90 shift-=depth;
91 while(shift<0){
92 shift+=8;
93 p++;
94 }
95 }else
96 p+= step;
97 *dst++= val;
98 }
99}