Alc/bformatdec.h

   1 #ifndef BFORMATDEC_H
   2 #define BFORMATDEC_H
   3
   4 #include "alMain.h"
   5
   6
   7 /* These are the necessary scales for first-order HF responses to play over
   8  * higher-order 2D (non-periphonic) decoders.
   9  */
  10 #define W_SCALE_2H0P   1.224744871f /* sqrt(1.5) */
  11 #define XYZ_SCALE_2H0P 1.0f
  12 #define W_SCALE_3H0P   1.414213562f /* sqrt(2) */
  13 #define XYZ_SCALE_3H0P 1.082392196f
  14
  15 /* These are the necessary scales for first-order HF responses to play over
  16  * higher-order 3D (periphonic) decoders.
  17  */
  18 #define W_SCALE_2H2P   1.341640787f /* sqrt(1.8) */
  19 #define XYZ_SCALE_2H2P 1.0f
  20 #define W_SCALE_3H3P   1.695486018f
  21 #define XYZ_SCALE_3H3P 1.136697713f
  22
  23
  24 /* NOTE: These are scale factors as applied to Ambisonics content. Decoder
  25  * coefficients should be divided by these values to get proper N3D scalings.
  26  */
  27 const ALfloat N3D2N3DScale[MAX_AMBI_COEFFS];
  28 const ALfloat SN3D2N3DScale[MAX_AMBI_COEFFS];
  29 const ALfloat FuMa2N3DScale[MAX_AMBI_COEFFS];
  30
  31
  32 struct AmbDecConf;
  33 struct BFormatDec;
  34 struct AmbiUpsampler;
  35
  36
  37 struct BFormatDec *bformatdec_alloc();
  38 void bformatdec_free(struct BFormatDec **dec);
  39 void bformatdec_reset(struct BFormatDec *dec, const struct AmbDecConf *conf, ALsizei chancount, ALuint srate, const ALsizei chanmap[MAX_OUTPUT_CHANNELS]);
  40
  41 /* Decodes the ambisonic input to the given output channels. */
  42 void bformatdec_process(struct BFormatDec *dec, ALfloat (*restrict OutBuffer)[BUFFERSIZE], ALsizei OutChannels, const ALfloat (*restrict InSamples)[BUFFERSIZE], ALsizei SamplesToDo);
  43
  44 /* Up-samples a first-order input to the decoder's configuration. */
  45 void bformatdec_upSample(struct BFormatDec *dec, ALfloat (*restrict OutBuffer)[BUFFERSIZE], const ALfloat (*restrict InSamples)[BUFFERSIZE], ALsizei InChannels, ALsizei SamplesToDo);
  46
  47
  48 /* Stand-alone first-order upsampler. Kept here because it shares some stuff
  49  * with bformatdec. Assumes a periphonic (4-channel) input mix!
  50  */
  51 struct AmbiUpsampler *ambiup_alloc();
  52 void ambiup_free(struct AmbiUpsampler **ambiup);
  53 void ambiup_reset(struct AmbiUpsampler *ambiup, const ALCdevice *device, ALfloat w_scale, ALfloat xyz_scale);
  54
  55 void ambiup_process(struct AmbiUpsampler *ambiup, ALfloat (*restrict OutBuffer)[BUFFERSIZE], ALsizei OutChannels, const ALfloat (*restrict InSamples)[BUFFERSIZE], ALsizei SamplesToDo);
  56
  57
  58 /* Band splitter. Splits a signal into two phase-matching frequency bands. */
  59 typedef struct BandSplitter {
  60     ALfloat coeff;
  61     ALfloat lp_z1;
  62     ALfloat lp_z2;
  63     ALfloat hp_z1;
  64 } BandSplitter;
  65
  66 void bandsplit_init(BandSplitter *splitter, ALfloat f0norm);
  67 void bandsplit_clear(BandSplitter *splitter);
  68 void bandsplit_process(BandSplitter *splitter, ALfloat *restrict hpout, ALfloat *restrict lpout,
  69                        const ALfloat *input, ALsizei count);
  70
  71 /* The all-pass portion of the band splitter. Applies the same phase shift
  72  * without splitting the signal.
  73  */
  74 typedef struct SplitterAllpass {
  75     ALfloat coeff;
  76     ALfloat z1;
  77 } SplitterAllpass;
  78
  79 void splitterap_init(SplitterAllpass *splitter, ALfloat f0norm);
  80 void splitterap_clear(SplitterAllpass *splitter);
  81 void splitterap_process(SplitterAllpass *splitter, ALfloat *restrict samples, ALsizei count);
  82
  83
  84 typedef struct FrontStablizer {
  85     SplitterAllpass APFilter[MAX_OUTPUT_CHANNELS];
  86     BandSplitter LFilter, RFilter;
  87     alignas(16) ALfloat LSplit[2][BUFFERSIZE];
  88     alignas(16) ALfloat RSplit[2][BUFFERSIZE];
  89 } FrontStablizer;
  90
  91 #endif /* BFORMATDEC_H */