kopia lustrzana https://github.com/espressif/esp-idf
48 wiersze
1.5 KiB
C
48 wiersze
1.5 KiB
C
/*
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* SPDX-FileCopyrightText: 2024 Espressif Systems (Shanghai) CO LTD
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <stdint.h>
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#include "driver/jpeg_types.h"
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#include "jpeg_private.h"
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/**
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* @brief Zigzag scan pattern array.
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*
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* This array represents a zigzag scan pattern for reordering the coefficients
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* in a block of data. It is commonly used in JPEG compression and decompression
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* algorithms to optimize encoding and decoding processes.
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*
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* The array consists of 64 elements, where each element represents the position
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* of a coefficient in the zigzag pattern. The coefficients are traversed in the
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* order specified by this array to achieve efficient compression and decompression.
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*
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* @note The values in this array are zero-indexed.
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*/
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const uint8_t zigzag_arr[64] = {
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0, 1, 8, 16, 9, 2, 3, 10,
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17, 24, 32, 25, 18, 11, 4, 5,
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12, 19, 26, 33, 40, 48, 41, 34,
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27, 20, 13, 6, 7, 14, 21, 28,
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35, 42, 49, 56, 57, 50, 43, 36,
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29, 22, 15, 23, 30, 37, 44, 51,
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58, 59, 52, 45, 38, 31, 39, 46,
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53, 60, 61, 54, 47, 55, 62, 63
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};
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/**
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* @brief DMA2D best hb value table for JPEG decompression.
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*
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* This two-dimensional array represents a Huffman decoding table for JPEG
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* decompression. It is used to decode the Huffman-coded symbols in the compressed
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* data stream during the decoding process.
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*/
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const uint32_t dec_hb_tbl[JPEG_DOWN_SAMPLING_MAX][JPEG_DEC_BEST_HB_MAX] = {
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{40, 40, 40, 32, 0},
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{64, 32, 32, 64, 0},
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{48, 32, 32, 48, 0},
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{96, 0, 0, 0, 96},
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};
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