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