/usr/include/webp/decode_vp8.h is in libwebp-dev 0.1.3-2.1ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 | // Copyright 2010 Google Inc.
//
// This code is licensed under the same terms as WebM:
// Software License Agreement: http://www.webmproject.org/license/software/
// Additional IP Rights Grant: http://www.webmproject.org/license/additional/
// -----------------------------------------------------------------------------
//
// Low-level API for VP8 decoder
//
// Author: Skal (pascal.massimino@gmail.com)
#ifndef WEBP_WEBP_DECODE_VP8_H_
#define WEBP_WEBP_DECODE_VP8_H_
#include "./decode.h"
#if defined(__cplusplus) || defined(c_plusplus)
extern "C" {
#endif
//------------------------------------------------------------------------------
// Lower-level API
//
// These functions provide fine-grained control of the decoding process.
// The call flow should resemble:
//
// VP8Io io;
// VP8InitIo(&io);
// io.data = data;
// io.data_size = size;
// /* customize io's functions (setup()/put()/teardown()) if needed. */
//
// VP8Decoder* dec = VP8New();
// bool ok = VP8Decode(dec);
// if (!ok) printf("Error: %s\n", VP8StatusMessage(dec));
// VP8Delete(dec);
// return ok;
// Input / Output
typedef struct VP8Io VP8Io;
typedef int (*VP8IoPutHook)(const VP8Io* io);
typedef int (*VP8IoSetupHook)(VP8Io* io);
typedef void (*VP8IoTeardownHook)(const VP8Io* io);
struct VP8Io {
// set by VP8GetHeaders()
int width, height; // picture dimensions, in pixels (invariable).
// These are the original, uncropped dimensions.
// The actual area passed to put() is stored
// in mb_w / mb_h fields.
// set before calling put()
int mb_y; // position of the current rows (in pixels)
int mb_w; // number of columns in the sample
int mb_h; // number of rows in the sample
const uint8_t* y, *u, *v; // rows to copy (in yuv420 format)
int y_stride; // row stride for luma
int uv_stride; // row stride for chroma
void* opaque; // user data
// called when fresh samples are available. Currently, samples are in
// YUV420 format, and can be up to width x 24 in size (depending on the
// in-loop filtering level, e.g.). Should return false in case of error
// or abort request. The actual size of the area to update is mb_w x mb_h
// in size, taking cropping into account.
VP8IoPutHook put;
// called just before starting to decode the blocks.
// Must return false in case of setup error, true otherwise. If false is
// returned, teardown() will NOT be called. But if the setup succeeded
// and true is returned, then teardown() will always be called afterward.
VP8IoSetupHook setup;
// Called just after block decoding is finished (or when an error occurred
// during put()). Is NOT called if setup() failed.
VP8IoTeardownHook teardown;
// this is a recommendation for the user-side yuv->rgb converter. This flag
// is set when calling setup() hook and can be overwritten by it. It then
// can be taken into consideration during the put() method.
int fancy_upsampling;
// Input buffer.
uint32_t data_size;
const uint8_t* data;
// If true, in-loop filtering will not be performed even if present in the
// bitstream. Switching off filtering may speed up decoding at the expense
// of more visible blocking. Note that output will also be non-compliant
// with the VP8 specifications.
int bypass_filtering;
// Cropping parameters.
int use_cropping;
int crop_left, crop_right, crop_top, crop_bottom;
// Scaling parameters.
int use_scaling;
int scaled_width, scaled_height;
// pointer to the alpha data (if present) corresponding to the rows
const uint8_t* a;
};
// Internal, version-checked, entry point
WEBP_EXTERN(int) VP8InitIoInternal(VP8Io* const, int);
// Set the custom IO function pointers and user-data. The setter for IO hooks
// should be called before initiating incremental decoding. Returns true if
// WebPIDecoder object is successfully modified, false otherwise.
WEBP_EXTERN(int) WebPISetIOHooks(WebPIDecoder* const idec,
VP8IoPutHook put,
VP8IoSetupHook setup,
VP8IoTeardownHook teardown,
void* user_data);
// Main decoding object. This is an opaque structure.
typedef struct VP8Decoder VP8Decoder;
// Create a new decoder object.
WEBP_EXTERN(VP8Decoder*) VP8New(void);
// Must be called to make sure 'io' is initialized properly.
// Returns false in case of version mismatch. Upon such failure, no other
// decoding function should be called (VP8Decode, VP8GetHeaders, ...)
static inline int VP8InitIo(VP8Io* const io) {
return VP8InitIoInternal(io, WEBP_DECODER_ABI_VERSION);
}
// Start decoding a new picture. Returns true if ok.
WEBP_EXTERN(int) VP8GetHeaders(VP8Decoder* const dec, VP8Io* const io);
// Decode a picture. Will call VP8GetHeaders() if it wasn't done already.
// Returns false in case of error.
WEBP_EXTERN(int) VP8Decode(VP8Decoder* const dec, VP8Io* const io);
// Return current status of the decoder:
WEBP_EXTERN(VP8StatusCode) VP8Status(VP8Decoder* const dec);
// return readable string corresponding to the last status.
WEBP_EXTERN(const char*) VP8StatusMessage(VP8Decoder* const dec);
// Resets the decoder in its initial state, reclaiming memory.
// Not a mandatory call between calls to VP8Decode().
WEBP_EXTERN(void) VP8Clear(VP8Decoder* const dec);
// Destroy the decoder object.
WEBP_EXTERN(void) VP8Delete(VP8Decoder* const dec);
//------------------------------------------------------------------------------
#if defined(__cplusplus) || defined(c_plusplus)
} // extern "C"
#endif
#endif /* WEBP_WEBP_DECODE_VP8_H_ */
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