133 lines
3.2 KiB
C
133 lines
3.2 KiB
C
/*
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* Copyright (c) 2010 The WebM project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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/****************************************************************************
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*
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* Module Title : boolhuff.h
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*
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* Description : Bool Coder header file.
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*
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****************************************************************************/
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#ifndef VP8_ENCODER_BOOLHUFF_H_
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#define VP8_ENCODER_BOOLHUFF_H_
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#include "vpx_ports/mem.h"
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#include "vpx/internal/vpx_codec_internal.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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typedef struct
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{
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unsigned int lowvalue;
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unsigned int range;
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int count;
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unsigned int pos;
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unsigned char *buffer;
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unsigned char *buffer_end;
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struct vpx_internal_error_info *error;
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} BOOL_CODER;
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extern void vp8_start_encode(BOOL_CODER *bc, unsigned char *buffer, unsigned char *buffer_end);
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extern void vp8_encode_value(BOOL_CODER *br, int data, int bits);
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extern void vp8_stop_encode(BOOL_CODER *bc);
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extern const unsigned int vp8_prob_cost[256];
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DECLARE_ALIGNED(16, extern const unsigned char, vp8_norm[256]);
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static int validate_buffer(const unsigned char *start,
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size_t len,
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const unsigned char *end,
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struct vpx_internal_error_info *error)
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{
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if (start + len > start && start + len < end)
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return 1;
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else
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vpx_internal_error(error, VPX_CODEC_CORRUPT_FRAME,
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"Truncated packet or corrupt partition ");
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return 0;
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}
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static void vp8_encode_bool(BOOL_CODER *br, int bit, int probability)
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{
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unsigned int split;
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int count = br->count;
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unsigned int range = br->range;
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unsigned int lowvalue = br->lowvalue;
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register unsigned int shift;
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#ifdef VP8_ENTROPY_STATS
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#if defined(SECTIONBITS_OUTPUT)
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if (bit)
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Sectionbits[active_section] += vp8_prob_cost[255-probability];
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else
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Sectionbits[active_section] += vp8_prob_cost[probability];
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#endif
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#endif
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split = 1 + (((range - 1) * probability) >> 8);
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range = split;
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if (bit)
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{
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lowvalue += split;
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range = br->range - split;
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}
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shift = vp8_norm[range];
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range <<= shift;
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count += shift;
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if (count >= 0)
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{
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int offset = shift - count;
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if ((lowvalue << (offset - 1)) & 0x80000000)
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{
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int x = br->pos - 1;
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while (x >= 0 && br->buffer[x] == 0xff)
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{
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br->buffer[x] = (unsigned char)0;
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x--;
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}
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br->buffer[x] += 1;
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}
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validate_buffer(br->buffer + br->pos, 1, br->buffer_end, br->error);
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br->buffer[br->pos++] = (lowvalue >> (24 - offset));
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lowvalue <<= offset;
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shift = count;
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lowvalue &= 0xffffff;
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count -= 8 ;
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}
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lowvalue <<= shift;
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br->count = count;
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br->lowvalue = lowvalue;
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br->range = range;
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}
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#ifdef __cplusplus
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} // extern "C"
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#endif
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#endif // VP8_ENCODER_BOOLHUFF_H_
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