| 1 | /* |
| 2 | * Shared functions between AMR codecs |
| 3 | * |
| 4 | * Copyright (c) 2010 Marcelo Galvao Povoa |
| 5 | * |
| 6 | * This file is part of FFmpeg. |
| 7 | * |
| 8 | * FFmpeg is free software; you can redistribute it and/or |
| 9 | * modify it under the terms of the GNU Lesser General Public |
| 10 | * License as published by the Free Software Foundation; either |
| 11 | * version 2.1 of the License, or (at your option) any later version. |
| 12 | * |
| 13 | * FFmpeg is distributed in the hope that it will be useful, |
| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 16 | * Lesser General Public License for more details. |
| 17 | * |
| 18 | * You should have received a copy of the GNU Lesser General Public |
| 19 | * License along with FFmpeg; if not, write to the Free Software |
| 20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 21 | */ |
| 22 | |
| 23 | #ifndef AVCODEC_AMR_H |
| 24 | #define AVCODEC_AMR_H |
| 25 | |
| 26 | #include <string.h> |
| 27 | |
| 28 | #include "avcodec.h" |
| 29 | |
| 30 | #ifdef AMR_USE_16BIT_TABLES |
| 31 | #define R_TABLE_TYPE uint16_t |
| 32 | #else |
| 33 | #define R_TABLE_TYPE uint8_t |
| 34 | #endif |
| 35 | |
| 36 | /** |
| 37 | * Fill the frame structure variables from bitstream by parsing the |
| 38 | * given reordering table that uses the following format: |
| 39 | * |
| 40 | * Each field (16 bits) in the AMR Frame is stored as: |
| 41 | * - one byte for the number of bits in the field |
| 42 | * - one byte for the field index |
| 43 | * - then, one byte for each bit of the field (from most-significant to least) |
| 44 | * of the position of that bit in the AMR frame. |
| 45 | * |
| 46 | * @param out pointer to the frame struct |
| 47 | * @param size the size in bytes of the frame struct |
| 48 | * @param data input bitstream after the frame header |
| 49 | * @param ord_table the reordering table as above |
| 50 | */ |
| 51 | static inline void ff_amr_bit_reorder(uint16_t *out, int size, |
| 52 | const uint8_t *data, |
| 53 | const R_TABLE_TYPE *ord_table) |
| 54 | { |
| 55 | int field_size; |
| 56 | |
| 57 | memset(out, 0, size); |
| 58 | while ((field_size = *ord_table++)) { |
| 59 | int field = 0; |
| 60 | int field_offset = *ord_table++; |
| 61 | while (field_size--) { |
| 62 | int bit = *ord_table++; |
| 63 | field <<= 1; |
| 64 | field |= data[bit >> 3] >> (bit & 7) & 1; |
| 65 | } |
| 66 | out[field_offset >> 1] = field; |
| 67 | } |
| 68 | } |
| 69 | |
| 70 | #endif /* AVCODEC_AMR_H */ |