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// 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
#define WEBP_DECODER_ABI_VERSION 0x0001
//-----------------------------------------------------------------------------
// Lower-level API
//
// Thes 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;
struct VP8Io {
// set by VP8GetHeaders()
int width, height; // picture dimensions, in pixels
// set before calling put()
int mb_y; // position of the current rows (in pixels)
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.
int (*put)(const VP8Io* io);
// called just before starting to decode the blocks.
// Should returns 0 in case of error.
int (*setup)(VP8Io* io);
// called just after block decoding is finished (or when an error occurred).
void (*teardown)(const VP8Io* io);
// 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_upscaling;
// 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;
};
// Internal, version-checked, entry point
extern int VP8InitIoInternal(VP8Io* const, int);
// Main decoding object. This is an opaque structure.
typedef struct VP8Decoder VP8Decoder;
// Create a new decoder object.
VP8Decoder* VP8New();
// 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.
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.
int VP8Decode(VP8Decoder* const dec, VP8Io* const io);
// Enumeration of the codes returned by VP8Status()
typedef enum {
VP8_STATUS_OK = 0,
VP8_STATUS_OUT_OF_MEMORY,
VP8_STATUS_INVALID_PARAM,
VP8_STATUS_BITSTREAM_ERROR,
VP8_STATUS_UNSUPPORTED_FEATURE,
VP8_STATUS_SUSPENDED,
VP8_STATUS_USER_ABORT,
VP8_STATUS_NOT_ENOUGH_DATA,
} VP8StatusCode;
// Return current status of the decoder:
VP8StatusCode VP8Status(VP8Decoder* const dec);
// return readable string corresponding to the last status.
const char* VP8StatusMessage(VP8Decoder* const dec);
// Resets the decoder in its initial state, reclaiming memory.
// Not a mandatory call between calls to VP8Decode().
void VP8Clear(VP8Decoder* const dec);
// Destroy the decoder object.
void VP8Delete(VP8Decoder* const dec);
//-----------------------------------------------------------------------------
#if defined(__cplusplus) || defined(c_plusplus)
} // extern "C"
#endif
#endif /* WEBP_WEBP_DECODE_VP8_H_ */
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