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Diffstat (limited to 'media/libwebp/webp/format_constants.h')
| -rw-r--r-- | media/libwebp/webp/format_constants.h | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/media/libwebp/webp/format_constants.h b/media/libwebp/webp/format_constants.h new file mode 100644 index 000000000..329fc8a3b --- /dev/null +++ b/media/libwebp/webp/format_constants.h @@ -0,0 +1,87 @@ +// Copyright 2012 Google Inc. All Rights Reserved. +// +// Use of this source code is governed by a BSD-style license +// that can be found in the COPYING file in the root of the source +// tree. An additional intellectual property rights grant can be found +// in the file PATENTS. All contributing project authors may +// be found in the AUTHORS file in the root of the source tree. +// ----------------------------------------------------------------------------- +// +// Internal header for constants related to WebP file format. +// +// Author: Urvang (urvang@google.com) + +#ifndef WEBP_WEBP_FORMAT_CONSTANTS_H_ +#define WEBP_WEBP_FORMAT_CONSTANTS_H_ + +// Create fourcc of the chunk from the chunk tag characters. +#define MKFOURCC(a, b, c, d) ((a) | (b) << 8 | (c) << 16 | (uint32_t)(d) << 24) + +// VP8 related constants. +#define VP8_SIGNATURE 0x9d012a // Signature in VP8 data. +#define VP8_MAX_PARTITION0_SIZE (1 << 19) // max size of mode partition +#define VP8_MAX_PARTITION_SIZE (1 << 24) // max size for token partition +#define VP8_FRAME_HEADER_SIZE 10 // Size of the frame header within VP8 data. + +// VP8L related constants. +#define VP8L_SIGNATURE_SIZE 1 // VP8L signature size. +#define VP8L_MAGIC_BYTE 0x2f // VP8L signature byte. +#define VP8L_IMAGE_SIZE_BITS 14 // Number of bits used to store + // width and height. +#define VP8L_VERSION_BITS 3 // 3 bits reserved for version. +#define VP8L_VERSION 0 // version 0 +#define VP8L_FRAME_HEADER_SIZE 5 // Size of the VP8L frame header. + +#define MAX_PALETTE_SIZE 256 +#define MAX_CACHE_BITS 11 +#define HUFFMAN_CODES_PER_META_CODE 5 +#define ARGB_BLACK 0xff000000 + +#define DEFAULT_CODE_LENGTH 8 +#define MAX_ALLOWED_CODE_LENGTH 15 + +#define NUM_LITERAL_CODES 256 +#define NUM_LENGTH_CODES 24 +#define NUM_DISTANCE_CODES 40 +#define CODE_LENGTH_CODES 19 + +#define MIN_HUFFMAN_BITS 2 // min number of Huffman bits +#define MAX_HUFFMAN_BITS 9 // max number of Huffman bits + +#define TRANSFORM_PRESENT 1 // The bit to be written when next data + // to be read is a transform. +#define NUM_TRANSFORMS 4 // Maximum number of allowed transform + // in a bitstream. +typedef enum { + PREDICTOR_TRANSFORM = 0, + CROSS_COLOR_TRANSFORM = 1, + SUBTRACT_GREEN = 2, + COLOR_INDEXING_TRANSFORM = 3 +} VP8LImageTransformType; + +// Alpha related constants. +#define ALPHA_HEADER_LEN 1 +#define ALPHA_NO_COMPRESSION 0 +#define ALPHA_LOSSLESS_COMPRESSION 1 +#define ALPHA_PREPROCESSED_LEVELS 1 + +// Mux related constants. +#define TAG_SIZE 4 // Size of a chunk tag (e.g. "VP8L"). +#define CHUNK_SIZE_BYTES 4 // Size needed to store chunk's size. +#define CHUNK_HEADER_SIZE 8 // Size of a chunk header. +#define RIFF_HEADER_SIZE 12 // Size of the RIFF header ("RIFFnnnnWEBP"). +#define ANMF_CHUNK_SIZE 16 // Size of an ANMF chunk. +#define ANIM_CHUNK_SIZE 6 // Size of an ANIM chunk. +#define VP8X_CHUNK_SIZE 10 // Size of a VP8X chunk. + +#define MAX_CANVAS_SIZE (1 << 24) // 24-bit max for VP8X width/height. +#define MAX_IMAGE_AREA (1ULL << 32) // 32-bit max for width x height. +#define MAX_LOOP_COUNT (1 << 16) // maximum value for loop-count +#define MAX_DURATION (1 << 24) // maximum duration +#define MAX_POSITION_OFFSET (1 << 24) // maximum frame x/y offset + +// Maximum chunk payload is such that adding the header and padding won't +// overflow a uint32_t. +#define MAX_CHUNK_PAYLOAD (~0U - CHUNK_HEADER_SIZE - 1) + +#endif /* WEBP_WEBP_FORMAT_CONSTANTS_H_ */ |