1 | // Copyright 2012 Google Inc. All Rights Reserved. |
2 | // |
3 | // Use of this source code is governed by a BSD-style license |
4 | // that can be found in the COPYING file in the root of the source |
5 | // tree. An additional intellectual property rights grant can be found |
6 | // in the file PATENTS. All contributing project authors may |
7 | // be found in the AUTHORS file in the root of the source tree. |
8 | // ----------------------------------------------------------------------------- |
9 | // |
10 | // Internal header for constants related to WebP file format. |
11 | // |
12 | // Author: Urvang (urvang@google.com) |
13 | |
14 | #ifndef WEBP_WEBP_FORMAT_CONSTANTS_H_ |
15 | #define WEBP_WEBP_FORMAT_CONSTANTS_H_ |
16 | |
17 | // Create fourcc of the chunk from the chunk tag characters. |
18 | #define MKFOURCC(a, b, c, d) ((a) | (b) << 8 | (c) << 16 | (uint32_t)(d) << 24) |
19 | |
20 | // VP8 related constants. |
21 | #define VP8_SIGNATURE 0x9d012a // Signature in VP8 data. |
22 | #define VP8_MAX_PARTITION0_SIZE (1 << 19) // max size of mode partition |
23 | #define VP8_MAX_PARTITION_SIZE (1 << 24) // max size for token partition |
24 | #define 10 // Size of the frame header within VP8 data. |
25 | |
26 | // VP8L related constants. |
27 | #define VP8L_SIGNATURE_SIZE 1 // VP8L signature size. |
28 | #define VP8L_MAGIC_BYTE 0x2f // VP8L signature byte. |
29 | #define VP8L_IMAGE_SIZE_BITS 14 // Number of bits used to store |
30 | // width and height. |
31 | #define VP8L_VERSION_BITS 3 // 3 bits reserved for version. |
32 | #define VP8L_VERSION 0 // version 0 |
33 | #define 5 // Size of the VP8L frame header. |
34 | |
35 | #define MAX_PALETTE_SIZE 256 |
36 | #define MAX_CACHE_BITS 11 |
37 | #define HUFFMAN_CODES_PER_META_CODE 5 |
38 | #define ARGB_BLACK 0xff000000 |
39 | |
40 | #define DEFAULT_CODE_LENGTH 8 |
41 | #define MAX_ALLOWED_CODE_LENGTH 15 |
42 | |
43 | #define NUM_LITERAL_CODES 256 |
44 | #define NUM_LENGTH_CODES 24 |
45 | #define NUM_DISTANCE_CODES 40 |
46 | #define CODE_LENGTH_CODES 19 |
47 | |
48 | #define MIN_HUFFMAN_BITS 2 // min number of Huffman bits |
49 | #define MAX_HUFFMAN_BITS 9 // max number of Huffman bits |
50 | |
51 | #define TRANSFORM_PRESENT 1 // The bit to be written when next data |
52 | // to be read is a transform. |
53 | #define NUM_TRANSFORMS 4 // Maximum number of allowed transform |
54 | // in a bitstream. |
55 | typedef enum { |
56 | PREDICTOR_TRANSFORM = 0, |
57 | CROSS_COLOR_TRANSFORM = 1, |
58 | SUBTRACT_GREEN = 2, |
59 | COLOR_INDEXING_TRANSFORM = 3 |
60 | } VP8LImageTransformType; |
61 | |
62 | // Alpha related constants. |
63 | #define 1 |
64 | #define ALPHA_NO_COMPRESSION 0 |
65 | #define ALPHA_LOSSLESS_COMPRESSION 1 |
66 | #define ALPHA_PREPROCESSED_LEVELS 1 |
67 | |
68 | // Mux related constants. |
69 | #define TAG_SIZE 4 // Size of a chunk tag (e.g. "VP8L"). |
70 | #define CHUNK_SIZE_BYTES 4 // Size needed to store chunk's size. |
71 | #define 8 // Size of a chunk header. |
72 | #define 12 // Size of the RIFF header ("RIFFnnnnWEBP"). |
73 | #define ANMF_CHUNK_SIZE 16 // Size of an ANMF chunk. |
74 | #define ANIM_CHUNK_SIZE 6 // Size of an ANIM chunk. |
75 | #define VP8X_CHUNK_SIZE 10 // Size of a VP8X chunk. |
76 | |
77 | #define MAX_CANVAS_SIZE (1 << 24) // 24-bit max for VP8X width/height. |
78 | #define MAX_IMAGE_AREA (1ULL << 32) // 32-bit max for width x height. |
79 | #define MAX_LOOP_COUNT (1 << 16) // maximum value for loop-count |
80 | #define MAX_DURATION (1 << 24) // maximum duration |
81 | #define MAX_POSITION_OFFSET (1 << 24) // maximum frame x/y offset |
82 | |
83 | // Maximum chunk payload is such that adding the header and padding won't |
84 | // overflow a uint32_t. |
85 | #define MAX_CHUNK_PAYLOAD (~0U - CHUNK_HEADER_SIZE - 1) |
86 | |
87 | #endif // WEBP_WEBP_FORMAT_CONSTANTS_H_ |
88 | |