ext/closedcaption/bit_slicer.h

   1 /*
   2  *  libzvbi -- Bit slicer
   3  *
   4  *  Copyright (C) 2000-2007 Michael H. Schimek
   5  *
   6  *  This library is free software; you can redistribute it and/or
   7  *  modify it under the terms of the GNU Library General Public
   8  *  License as published by the Free Software Foundation; either
   9  *  version 2 of the License, or (at your option) any later version.
  10  *
  11  *  This library is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  *  Library General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU Library General Public
  17  *  License along with this library; if not, write to the
  18  *  Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  19  *  Boston, MA  02110-1301  USA.
  20  */
  21
  22 /* $Id: bit_slicer.h,v 1.11 2008-02-24 14:18:13 mschimek Exp $ */
  23
  24 #ifndef __ZVBI_BIT_SLICER_H__
  25 #define __ZVBI_BIT_SLICER_H__
  26
  27 #include "sampling_par.h"
  28
  29 VBI_BEGIN_DECLS
  30
  31 /**
  32  * @addtogroup BitSlicer
  33  * @{
  34  */
  35
  36 /**
  37  * @brief Modulation used for VBI data transmission.
  38  */
  39 typedef enum {
  40         /**
  41          * The data is 'non-return to zero' coded, logical '1' bits
  42          * are described by high sample values, logical '0' bits by
  43          * low values. The data is last significant bit first transmitted.
  44          */
  45         VBI3_MODULATION_NRZ_LSB,
  46
  47         /**
  48          * 'Non-return to zero' coded, most significant bit first
  49          * transmitted.
  50          */
  51         VBI3_MODULATION_NRZ_MSB,
  52
  53         /**
  54          * The data is 'bi-phase' coded. Each data bit is described
  55          * by two complementary signalling elements, a logical '1'
  56          * by a sequence of '10' elements, a logical '0' by a '01'
  57          * sequence. The data is last significant bit first transmitted.
  58          */
  59         VBI3_MODULATION_BIPHASE_LSB,
  60
  61         /** 'Bi-phase' coded, most significant bit first transmitted. */
  62         VBI3_MODULATION_BIPHASE_MSB
  63 } vbi3_modulation;
  64
  65 /**
  66  * @brief Bit slicer context.
  67  *
  68  * The contents of this structure are private.
  69  * Call vbi3_bit_slicer_new() to allocate a bit slicer context.
  70  */
  71 typedef struct _vbi3_bit_slicer vbi3_bit_slicer;
  72
  73 typedef enum {
  74         VBI3_CRI_BIT = 1,
  75         VBI3_FRC_BIT,
  76         VBI3_PAYLOAD_BIT
  77 } vbi3_bit_slicer_bit;
  78
  79 /**
  80  * @brief Bit slicer sampling point.
  81  *
  82  * This structure contains information about
  83  * a bit sampled by the bit slicer.
  84  */
  85 typedef struct {
  86         /** Whether this struct refers to a CRI, FRC or payload bit. */
  87         vbi3_bit_slicer_bit     kind;
  88
  89         /** Number of the sample times 256. */
  90         unsigned int            index;
  91
  92         /** Signal amplitude at this sample, in range 0 to 65535. */
  93         unsigned int            level;
  94
  95         /** 0/1 threshold at this sample, in range 0 to 65535. */
  96         unsigned int            thresh;
  97 } vbi3_bit_slicer_point;
  98
  99 extern vbi_bool
 100 vbi3_bit_slicer_slice_with_points
 101                                 (vbi3_bit_slicer *      bs,
 102                                  uint8_t *              buffer,
 103                                  unsigned int           buffer_size,
 104                                  vbi3_bit_slicer_point *points,
 105                                  unsigned int *         n_points,
 106                                  unsigned int           max_points,
 107                                  const uint8_t *        raw)
 108   _vbi_nonnull ((1, 2, 4, 5, 7));
 109 extern vbi_bool
 110 vbi3_bit_slicer_slice           (vbi3_bit_slicer *      bs,
 111                                  uint8_t *              buffer,
 112                                  unsigned int           buffer_size,
 113                                  const uint8_t *        raw)
 114   _vbi_nonnull ((1, 2, 4));
 115 extern vbi_bool
 116 vbi3_bit_slicer_set_params      (vbi3_bit_slicer *      bs,
 117                                  vbi_pixfmt             sample_format,
 118                                  unsigned int           sampling_rate,
 119                                  unsigned int           sample_offset,
 120                                  unsigned int           samples_per_line,
 121                                  unsigned int           cri,
 122                                  unsigned int           cri_mask,
 123                                  unsigned int           cri_bits,
 124                                  unsigned int           cri_rate,
 125                                  unsigned int           cri_end,
 126                                  unsigned int           frc,
 127                                  unsigned int           frc_bits,
 128                                  unsigned int           payload_bits,
 129                                  unsigned int           payload_rate,
 130                                  vbi3_modulation        modulation)
 131   _vbi_nonnull ((1));
 132 extern void
 133 vbi3_bit_slicer_set_log_fn      (vbi3_bit_slicer *      bs,
 134                                  vbi_log_mask           mask,
 135                                  vbi_log_fn *           log_fn,
 136                                  void *                 user_data)
 137   _vbi_nonnull ((1));
 138 extern void
 139 vbi3_bit_slicer_delete          (vbi3_bit_slicer *      bs);
 140 extern vbi3_bit_slicer *
 141 vbi3_bit_slicer_new             (void)
 142   _vbi_alloc;
 143
 144 /* Private */
 145
 146 typedef vbi_bool
 147 _vbi3_bit_slicer_fn             (vbi3_bit_slicer *      bs,
 148                                  uint8_t *              buffer,
 149                                  vbi3_bit_slicer_point *points,
 150                                  unsigned int *         n_points,
 151                                  const uint8_t *        raw);
 152
 153 /** @internal */
 154 struct _vbi3_bit_slicer {
 155         _vbi3_bit_slicer_fn *   func;
 156
 157         vbi_pixfmt              sample_format;
 158         unsigned int            cri;
 159         unsigned int            cri_mask;
 160         unsigned int            thresh;
 161         unsigned int            thresh_frac;
 162         unsigned int            cri_samples;
 163         unsigned int            cri_rate;
 164         unsigned int            oversampling_rate;
 165         unsigned int            phase_shift;
 166         unsigned int            step;
 167         unsigned int            frc;
 168         unsigned int            frc_bits;
 169         unsigned int            total_bits;
 170         unsigned int            payload;
 171         unsigned int            endian;
 172         unsigned int            bytes_per_sample;
 173         unsigned int            skip;
 174         unsigned int            green_mask;
 175
 176         _vbi_log_hook           log;
 177 };
 178
 179 extern void
 180 _vbi3_bit_slicer_destroy        (vbi3_bit_slicer *      bs)
 181   _vbi_nonnull ((1));
 182 extern vbi_bool
 183 _vbi3_bit_slicer_init           (vbi3_bit_slicer *      bs)
 184   _vbi_nonnull ((1));
 185
 186 /** @} */
 187
 188 VBI_END_DECLS
 189
 190 #endif /* __ZVBI_BIT_SLICER_H__ */
 191
 192 /*
 193 Local variables:
 194 c-set-style: K&R
 195 c-basic-offset: 8
 196 End:
 197 */