Subversion Repositories Kolibri OS

Rev

Go to most recent revision | Blame | Last modification | View Log | RSS feed

  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 */
  71.