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139 lines
6.8 KiB
139 lines
6.8 KiB
/* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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#ifndef AVCODEC_VLC_H |
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#define AVCODEC_VLC_H |
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#include <stdint.h> |
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#define VLC_TYPE int16_t |
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typedef struct VLC { |
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int bits; |
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VLC_TYPE (*table)[2]; ///< code, bits |
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int table_size, table_allocated; |
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} VLC; |
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typedef struct RL_VLC_ELEM { |
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int16_t level; |
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int8_t len; |
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uint8_t run; |
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} RL_VLC_ELEM; |
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#define init_vlc(vlc, nb_bits, nb_codes, \ |
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bits, bits_wrap, bits_size, \ |
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codes, codes_wrap, codes_size, \ |
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flags) \ |
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ff_init_vlc_sparse(vlc, nb_bits, nb_codes, \ |
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bits, bits_wrap, bits_size, \ |
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codes, codes_wrap, codes_size, \ |
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NULL, 0, 0, flags) |
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int ff_init_vlc_sparse(VLC *vlc, int nb_bits, int nb_codes, |
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const void *bits, int bits_wrap, int bits_size, |
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const void *codes, int codes_wrap, int codes_size, |
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const void *symbols, int symbols_wrap, int symbols_size, |
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int flags); |
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/** |
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* Build VLC decoding tables suitable for use with get_vlc2() |
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* |
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* This function takes lengths and symbols and calculates the codes from them. |
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* For this the input lengths and symbols have to be sorted according to "left |
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* nodes in the corresponding tree first". |
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* |
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* @param[in,out] vlc The VLC to be initialized; table and table_allocated |
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* must have been set when initializing a static VLC, |
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* otherwise this will be treated as uninitialized. |
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* @param[in] nb_bits The number of bits to use for the VLC table; |
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* higher values take up more memory and cache, but |
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* allow to read codes with fewer reads. |
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* @param[in] nb_codes The number of provided length and (if supplied) symbol |
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* entries. |
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* @param[in] lens The lengths of the codes. Entries > 0 correspond to |
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* valid codes; entries == 0 will be skipped and entries |
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* with len < 0 indicate that the tree is incomplete and |
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* has an open end of length -len at this position. |
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* @param[in] lens_wrap Stride (in bytes) of the lengths. |
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* @param[in] symbols The symbols, i.e. what is returned from get_vlc2() |
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* when the corresponding code is encountered. |
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* May be NULL, then 0, 1, 2, 3, 4,... will be used. |
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* @param[in] symbols_wrap Stride (in bytes) of the symbols. |
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* @param[in] symbols_size Size of the symbols. 1 and 2 are supported. |
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* @param[in] offset An offset to apply to all the valid symbols. |
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* @param[in] flags A combination of the INIT_VLC_* flags; notice that |
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* INIT_VLC_INPUT_LE is pointless and ignored. |
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*/ |
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int ff_init_vlc_from_lengths(VLC *vlc, int nb_bits, int nb_codes, |
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const int8_t *lens, int lens_wrap, |
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const void *symbols, int symbols_wrap, int symbols_size, |
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int offset, int flags, void *logctx); |
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void ff_free_vlc(VLC *vlc); |
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/* If INIT_VLC_INPUT_LE is set, the LSB bit of the codes used to |
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* initialize the VLC table is the first bit to be read. */ |
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#define INIT_VLC_INPUT_LE 2 |
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/* If set the VLC is intended for a little endian bitstream reader. */ |
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#define INIT_VLC_OUTPUT_LE 8 |
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#define INIT_VLC_LE (INIT_VLC_INPUT_LE | INIT_VLC_OUTPUT_LE) |
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#define INIT_VLC_USE_NEW_STATIC 4 |
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#define INIT_VLC_STATIC_OVERLONG (1 | INIT_VLC_USE_NEW_STATIC) |
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#define INIT_CUSTOM_VLC_SPARSE_STATIC(vlc, bits, a, b, c, d, e, f, g, \ |
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h, i, j, flags, static_size) \ |
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do { \ |
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static VLC_TYPE table[static_size][2]; \ |
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(vlc)->table = table; \ |
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(vlc)->table_allocated = static_size; \ |
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ff_init_vlc_sparse(vlc, bits, a, b, c, d, e, f, g, h, i, j, \ |
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flags | INIT_VLC_USE_NEW_STATIC); \ |
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} while (0) |
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#define INIT_VLC_SPARSE_STATIC(vlc, bits, a, b, c, d, e, f, g, h, i, j, static_size) \ |
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INIT_CUSTOM_VLC_SPARSE_STATIC(vlc, bits, a, b, c, d, e, f, g, \ |
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h, i, j, 0, static_size) |
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#define INIT_LE_VLC_SPARSE_STATIC(vlc, bits, a, b, c, d, e, f, g, h, i, j, static_size) \ |
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INIT_CUSTOM_VLC_SPARSE_STATIC(vlc, bits, a, b, c, d, e, f, g, \ |
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h, i, j, INIT_VLC_LE, static_size) |
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#define INIT_CUSTOM_VLC_STATIC(vlc, bits, a, b, c, d, e, f, g, flags, static_size) \ |
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INIT_CUSTOM_VLC_SPARSE_STATIC(vlc, bits, a, b, c, d, e, f, g, \ |
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NULL, 0, 0, flags, static_size) |
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#define INIT_VLC_STATIC(vlc, bits, a, b, c, d, e, f, g, static_size) \ |
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INIT_VLC_SPARSE_STATIC(vlc, bits, a, b, c, d, e, f, g, NULL, 0, 0, static_size) |
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#define INIT_LE_VLC_STATIC(vlc, bits, a, b, c, d, e, f, g, static_size) \ |
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INIT_LE_VLC_SPARSE_STATIC(vlc, bits, a, b, c, d, e, f, g, NULL, 0, 0, static_size) |
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#define INIT_VLC_STATIC_FROM_LENGTHS(vlc, bits, nb_codes, lens, len_wrap, \ |
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symbols, symbols_wrap, symbols_size, \ |
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offset, flags, static_size) \ |
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do { \ |
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static VLC_TYPE table[static_size][2]; \ |
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(vlc)->table = table; \ |
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(vlc)->table_allocated = static_size; \ |
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ff_init_vlc_from_lengths(vlc, bits, nb_codes, lens, len_wrap, \ |
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symbols, symbols_wrap, symbols_size, \ |
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offset, flags | INIT_VLC_USE_NEW_STATIC, \ |
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NULL); \ |
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} while (0) |
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#endif /* AVCODEC_VLC_H */
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