FFmpeg/libavutil/tx_priv.h

/*
 * 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 AVUTIL_TX_PRIV_H
#define AVUTIL_TX_PRIV_H

#include "tx.h"
#include "thread.h"
#include "mem_internal.h"
#include "attributes.h"

#ifdef TX_FLOAT
#define TX_TAB(x) x ## _float
#define TX_NAME(x) x ## _float_c
#define TX_NAME_STR(x) x "_float_c"
#define TX_TYPE(x) AV_TX_FLOAT_ ## x
#define MULT(x, m) ((x) * (m))
#define SCALE_TYPE float
typedef float TXSample;
typedef AVComplexFloat TXComplex;
#elif defined(TX_DOUBLE)
#define TX_TAB(x) x ## _double
#define TX_NAME(x) x ## _double_c
#define TX_NAME_STR(x) x "_double_c"
#define TX_TYPE(x) AV_TX_DOUBLE_ ## x
#define MULT(x, m) ((x) * (m))
#define SCALE_TYPE double
typedef double TXSample;
typedef AVComplexDouble TXComplex;
#elif defined(TX_INT32)
#define TX_TAB(x) x ## _int32
#define TX_NAME(x) x ## _int32_c
#define TX_NAME_STR(x) x "_int32_c"
#define TX_TYPE(x) AV_TX_INT32_ ## x
#define MULT(x, m) (((((int64_t)(x)) * (int64_t)(m)) + 0x40000000) >> 31)
#define SCALE_TYPE float
typedef int32_t TXSample;
typedef AVComplexInt32 TXComplex;
#else
typedef void TXComplex;
#endif

#if defined(TX_FLOAT) || defined(TX_DOUBLE)

#define CMUL(dre, dim, are, aim, bre, bim)      \
    do {                                        \
        (dre) = (are) * (bre) - (aim) * (bim);  \
        (dim) = (are) * (bim) + (aim) * (bre);  \
    } while (0)

#define SMUL(dre, dim, are, aim, bre, bim)      \
    do {                                        \
        (dre) = (are) * (bre) - (aim) * (bim);  \
        (dim) = (are) * (bim) - (aim) * (bre);  \
    } while (0)

#define UNSCALE(x) (x)
#define RESCALE(x) (x)

#define FOLD(a, b) ((a) + (b))

#elif defined(TX_INT32)

/* Properly rounds the result */
#define CMUL(dre, dim, are, aim, bre, bim)             \
    do {                                               \
        int64_t accu;                                  \
        (accu)  = (int64_t)(bre) * (are);              \
        (accu) -= (int64_t)(bim) * (aim);              \
        (dre)   = (int)(((accu) + 0x40000000) >> 31);  \
        (accu)  = (int64_t)(bim) * (are);              \
        (accu) += (int64_t)(bre) * (aim);              \
        (dim)   = (int)(((accu) + 0x40000000) >> 31);  \
    } while (0)

#define SMUL(dre, dim, are, aim, bre, bim)             \
    do {                                               \
        int64_t accu;                                  \
        (accu)  = (int64_t)(bre) * (are);              \
        (accu) -= (int64_t)(bim) * (aim);              \
        (dre)   = (int)(((accu) + 0x40000000) >> 31);  \
        (accu)  = (int64_t)(bim) * (are);              \
        (accu) -= (int64_t)(bre) * (aim);              \
        (dim)   = (int)(((accu) + 0x40000000) >> 31);  \
    } while (0)

#define UNSCALE(x) ((double)(x)/2147483648.0)
#define RESCALE(x) (av_clip64(lrintf((x) * 2147483648.0), INT32_MIN, INT32_MAX))

#define FOLD(x, y) ((int32_t)((x) + (unsigned)(y) + 32) >> 6)

#endif /* TX_INT32 */

#define BF(x, y, a, b)  \
    do {                \
        x = (a) - (b);  \
        y = (a) + (b);  \
    } while (0)

#define CMUL3(c, a, b) CMUL((c).re, (c).im, (a).re, (a).im, (b).re, (b).im)

/* Codelet flags, used to pick codelets. Must be a superset of enum AVTXFlags,
 * but if it runs out of bits, it can be made separate. */
#define FF_TX_OUT_OF_PLACE (1ULL << 63) /* Can be OR'd with AV_TX_INPLACE             */
#define FF_TX_ALIGNED      (1ULL << 62) /* Cannot be OR'd with AV_TX_UNALIGNED        */
#define FF_TX_PRESHUFFLE   (1ULL << 61) /* Codelet expects permuted coeffs            */
#define FF_TX_INVERSE_ONLY (1ULL << 60) /* For non-orthogonal inverse-only transforms */
#define FF_TX_FORWARD_ONLY (1ULL << 59) /* For non-orthogonal forward-only transforms */

typedef enum FFTXCodeletPriority {
    FF_TX_PRIO_BASE = 0,               /* Baseline priority */

    /* For SIMD, set base prio to the register size in bits and increment in
     * steps of 64 depending on faster/slower features, like FMA. */

    FF_TX_PRIO_MIN          = -131072, /* For naive implementations */
    FF_TX_PRIO_MAX          =  32768,  /* For custom implementations/ASICs */
} FFTXCodeletPriority;

/* Codelet options */
typedef struct FFTXCodeletOptions {
    int invert_lookup;     /* If codelet is flagged as FF_TX_CODELET_PRESHUFFLE,
                              invert the lookup direction for the map generated */
} FFTXCodeletOptions;

/* Maximum amount of subtransform functions, subtransforms and factors. Arbitrary. */
#define TX_MAX_SUB 4

typedef struct FFTXCodelet {
    const char    *name;          /* Codelet name, for debugging */
    av_tx_fn       function;      /* Codelet function, != NULL */
    enum AVTXType  type;          /* Type of codelet transform */
#define TX_TYPE_ANY INT32_MAX     /* Special type to allow all types */

    uint64_t flags;               /* A combination of AVTXFlags and codelet
                                   * flags that describe its properties. */

    int factors[TX_MAX_SUB];      /* Length factors */
#define TX_FACTOR_ANY -1          /* When used alone, signals that the codelet
                                   * supports all factors. Otherwise, if other
                                   * factors are present, it signals that whatever
                                   * remains will be supported, as long as the
                                   * other factors are a component of the length */

    int min_len;                  /* Minimum length of transform, must be >= 1 */
    int max_len;                  /* Maximum length of transform */
#define TX_LEN_UNLIMITED -1       /* Special length value to permit all lengths */

    int (*init)(AVTXContext *s,   /* Optional callback for current context initialization. */
                const struct FFTXCodelet *cd,
                uint64_t flags,
                FFTXCodeletOptions *opts,
                int len, int inv,
                const void *scale);

    int (*uninit)(AVTXContext *s); /* Optional callback for uninitialization. */

    int cpu_flags;                 /* CPU flags. If any negative flags like
                                    * SLOW are present, will avoid picking.
                                    * 0x0 to signal it's a C codelet */
#define FF_TX_CPU_FLAGS_ALL 0x0    /* Special CPU flag for C */

    int prio;                      /* < 0 = least, 0 = no pref, > 0 = prefer */
} FFTXCodelet;

struct AVTXContext {
    /* Fields the root transform and subtransforms use or may use.
     * NOTE: This section is used by assembly, do not reorder or change */
    int                len;             /* Length of the transform */
    int                inv;             /* If transform is inverse */
    int               *map;             /* Lookup table(s) */
    TXComplex         *exp;             /* Any non-pre-baked multiplication factors needed */
    TXComplex         *tmp;             /* Temporary buffer, if needed */

    AVTXContext       *sub;             /* Subtransform context(s), if needed */
    av_tx_fn           fn[TX_MAX_SUB];  /* Function(s) for the subtransforms */
    int                nb_sub;          /* Number of subtransforms.
                                         * The reason all of these are set here
                                         * rather than in each separate context
                                         * is to eliminate extra pointer
                                         * dereferences. */

    /* Fields mainly useul/applicable for the root transform or initialization.
     * Fields below are not used by assembly code. */
    const FFTXCodelet *cd[TX_MAX_SUB];  /* Subtransform codelets */
    const FFTXCodelet *cd_self;         /* Codelet for the current context */
    enum AVTXType      type;            /* Type of transform */
    uint64_t           flags;           /* A combination of AVTXFlags and
                                         * codelet flags used when creating */
    float              scale_f;
    double             scale_d;
    void              *opaque;          /* Free to use by implementations */
};

/* Create a subtransform in the current context with the given parameters.
 * The flags parameter from FFTXCodelet.init() should be preserved as much
 * as that's possible.
 * MUST be called during the sub() callback of each codelet. */
int ff_tx_init_subtx(AVTXContext *s, enum AVTXType type,
                     uint64_t flags, FFTXCodeletOptions *opts,
                     int len, int inv, const void *scale);

/*
 * Generates the PFA permutation table into AVTXContext->pfatab. The end table
 * is appended to the start table.
 */
int ff_tx_gen_compound_mapping(AVTXContext *s, int n, int m);

/*
 * Generates a standard-ish (slightly modified) Split-Radix revtab into
 * AVTXContext->map. Invert lookup changes how the mapping needs to be applied.
 * If it's set to 0, it has to be applied like out[map[i]] = in[i], otherwise
 * if it's set to 1, has to be applied as out[i] = in[map[i]]
 */
int ff_tx_gen_ptwo_revtab(AVTXContext *s, int invert_lookup);

/*
 * Generates an index into AVTXContext->inplace_idx that if followed in the
 * specific order, allows the revtab to be done in-place. The sub-transform
 * and its map should already be initialized.
 */
int ff_tx_gen_ptwo_inplace_revtab_idx(AVTXContext *s);

/*
 * This generates a parity-based revtab of length len and direction inv.
 *
 * Parity means even and odd complex numbers will be split, e.g. the even
 * coefficients will come first, after which the odd coefficients will be
 * placed. For example, a 4-point transform's coefficients after reordering:
 * z[0].re, z[0].im, z[2].re, z[2].im, z[1].re, z[1].im, z[3].re, z[3].im
 *
 * The basis argument is the length of the largest non-composite transform
 * supported, and also implies that the basis/2 transform is supported as well,
 * as the split-radix algorithm requires it to be.
 *
 * The dual_stride argument indicates that both the basis, as well as the
 * basis/2 transforms support doing two transforms at once, and the coefficients
 * will be interleaved between each pair in a split-radix like so (stride == 2):
 * tx1[0], tx1[2], tx2[0], tx2[2], tx1[1], tx1[3], tx2[1], tx2[3]
 * A non-zero number switches this on, with the value indicating the stride
 * (how many values of 1 transform to put first before switching to the other).
 * Must be a power of two or 0. Must be less than the basis.
 * Value will be clipped to the transform size, so for a basis of 16 and a
 * dual_stride of 8, dual 8-point transforms will be laid out as if dual_stride
 * was set to 4.
 * Usually you'll set this to half the complex numbers that fit in a single
 * register or 0. This allows to reuse SSE functions as dual-transform
 * functions in AVX mode.
 *
 * If length is smaller than basis/2 this function will not do anything.
 */
int ff_tx_gen_split_radix_parity_revtab(AVTXContext *s, int invert_lookup,
                                        int basis, int dual_stride);

/* Typed init function to initialize shared tables. Will initialize all tables
 * for all factors of a length. */
void ff_tx_init_tabs_float (int len);
void ff_tx_init_tabs_double(int len);
void ff_tx_init_tabs_int32 (int len);

/* Typed init function to initialize an MDCT exptab in a context. */
int  ff_tx_mdct_gen_exp_float (AVTXContext *s);
int  ff_tx_mdct_gen_exp_double(AVTXContext *s);
int  ff_tx_mdct_gen_exp_int32 (AVTXContext *s);

/* Lists of codelets */
extern const FFTXCodelet * const ff_tx_codelet_list_float_c       [];
extern const FFTXCodelet * const ff_tx_codelet_list_float_x86     [];

extern const FFTXCodelet * const ff_tx_codelet_list_double_c      [];

extern const FFTXCodelet * const ff_tx_codelet_list_int32_c       [];

#endif /* AVUTIL_TX_PRIV_H */