x264.h

/*****************************************************************************
 * x264.h: x264 public header
 *****************************************************************************
 * Copyright (C) 2003-2011 x264 project
 *
 * Authors: Laurent Aimar <fenrir@via.ecp.fr>
 *          Loren Merritt <lorenm@u.washington.edu>
 *          Jason Garrett-Glaser <darkshikari@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02111, USA.
 *
 * This program is also available under a commercial proprietary license.
 * For more information, contact us at licensing@x264.com.
 *****************************************************************************/

#ifndef X264_X264_H
#define X264_X264_H

#if !defined(_STDINT_H) && !defined(_STDINT_H_) && \
    !defined(_INTTYPES_H) && !defined(_INTTYPES_H_)
# ifdef _MSC_VER
#  pragma message("You must include stdint.h or inttypes.h before x264.h")
# else
#  warning You must include stdint.h or inttypes.h before x264.h
# endif
#endif

#include <stdarg.h>

#include "x264_config.h"

#define X264_BUILD 115

/* x264_t:
 *      opaque handler for encoder */
typedef struct x264_t x264_t;

/****************************************************************************
 * NAL structure and functions
 ****************************************************************************/

enum nal_unit_type_e
{
    NAL_UNKNOWN     = 0,
    NAL_SLICE       = 1,
    NAL_SLICE_DPA   = 2,
    NAL_SLICE_DPB   = 3,
    NAL_SLICE_DPC   = 4,
    NAL_SLICE_IDR   = 5,    /* ref_idc != 0 */
    NAL_SEI         = 6,    /* ref_idc == 0 */
    NAL_SPS         = 7,
    NAL_PPS         = 8,
    NAL_AUD         = 9,
    NAL_FILLER      = 12,
    /* ref_idc == 0 for 6,9,10,11,12 */
};
enum nal_priority_e
{
    NAL_PRIORITY_DISPOSABLE = 0,
    NAL_PRIORITY_LOW        = 1,
    NAL_PRIORITY_HIGH       = 2,
    NAL_PRIORITY_HIGHEST    = 3,
};

/* The data within the payload is already NAL-encapsulated; the ref_idc and type
 * are merely in the struct for easy access by the calling application.
 * All data returned in an x264_nal_t, including the data in p_payload, is no longer
 * valid after the next call to x264_encoder_encode.  Thus it must be used or copied
 * before calling x264_encoder_encode or x264_encoder_headers again. */
typedef struct
{
    int i_ref_idc;  /* nal_priority_e */
    int i_type;     /* nal_unit_type_e */
    int b_long_startcode;
    int i_first_mb; /* If this NAL is a slice, the index of the first MB in the slice. */
    int i_last_mb;  /* If this NAL is a slice, the index of the last MB in the slice. */

    /* Size of payload in bytes. */
    int     i_payload;
    /* If param->b_annexb is set, Annex-B bytestream with startcode.
     * Otherwise, startcode is replaced with a 4-byte size.
     * This size is the size used in mp4/similar muxing; it is equal to i_payload-4 */
    uint8_t *p_payload;
} x264_nal_t;

/****************************************************************************
 * Encoder parameters
 ****************************************************************************/
/* CPU flags
 */
#define X264_CPU_CACHELINE_32   0x000001  /* avoid memory loads that span the border between two cachelines */
#define X264_CPU_CACHELINE_64   0x000002  /* 32/64 is the size of a cacheline in bytes */
#define X264_CPU_ALTIVEC        0x000004
#define X264_CPU_MMX            0x000008
#define X264_CPU_MMXEXT         0x000010  /* MMX2 aka MMXEXT aka ISSE */
#define X264_CPU_SSE            0x000020
#define X264_CPU_SSE2           0x000040
#define X264_CPU_SSE2_IS_SLOW   0x000080  /* avoid most SSE2 functions on Athlon64 */
#define X264_CPU_SSE2_IS_FAST   0x000100  /* a few functions are only faster on Core2 and Phenom */
#define X264_CPU_SSE3           0x000200
#define X264_CPU_SSSE3          0x000400
#define X264_CPU_SHUFFLE_IS_FAST 0x000800 /* Penryn, Nehalem, and Phenom have fast shuffle units */
#define X264_CPU_STACK_MOD4     0x001000  /* if stack is only mod4 and not mod16 */
#define X264_CPU_SSE4           0x002000  /* SSE4.1 */
#define X264_CPU_SSE42          0x004000  /* SSE4.2 */
#define X264_CPU_SSE_MISALIGN   0x008000  /* Phenom support for misaligned SSE instruction arguments */
#define X264_CPU_LZCNT          0x010000  /* Phenom support for "leading zero count" instruction. */
#define X264_CPU_ARMV6          0x020000
#define X264_CPU_NEON           0x040000  /* ARM NEON */
#define X264_CPU_FAST_NEON_MRC  0x080000  /* Transfer from NEON to ARM register is fast (Cortex-A9) */
#define X264_CPU_SLOW_CTZ       0x100000  /* BSR/BSF x86 instructions are really slow on some CPUs */
#define X264_CPU_SLOW_ATOM      0x200000  /* The Atom just sucks */
#define X264_CPU_AVX            0x400000  /* AVX support: requires OS support even if YMM registers
                                           * aren't used. */

/* Analyse flags
 */
#define X264_ANALYSE_I4x4       0x0001  /* Analyse i4x4 */
#define X264_ANALYSE_I8x8       0x0002  /* Analyse i8x8 (requires 8x8 transform) */
#define X264_ANALYSE_PSUB16x16  0x0010  /* Analyse p16x8, p8x16 and p8x8 */
#define X264_ANALYSE_PSUB8x8    0x0020  /* Analyse p8x4, p4x8, p4x4 */
#define X264_ANALYSE_BSUB16x16  0x0100  /* Analyse b16x8, b8x16 and b8x8 */
#define X264_DIRECT_PRED_NONE        0
#define X264_DIRECT_PRED_SPATIAL     1
#define X264_DIRECT_PRED_TEMPORAL    2
#define X264_DIRECT_PRED_AUTO        3
#define X264_ME_DIA                  0
#define X264_ME_HEX                  1
#define X264_ME_UMH                  2
#define X264_ME_ESA                  3
#define X264_ME_TESA                 4
#define X264_CQM_FLAT                0
#define X264_CQM_JVT                 1
#define X264_CQM_CUSTOM              2
#define X264_RC_CQP                  0
#define X264_RC_CRF                  1
#define X264_RC_ABR                  2
#define X264_QP_AUTO                 0
#define X264_AQ_NONE                 0
#define X264_AQ_VARIANCE             1
#define X264_AQ_AUTOVARIANCE         2
#define X264_B_ADAPT_NONE            0
#define X264_B_ADAPT_FAST            1
#define X264_B_ADAPT_TRELLIS         2
#define X264_WEIGHTP_NONE            0
#define X264_WEIGHTP_SIMPLE          1
#define X264_WEIGHTP_SMART           2
#define X264_B_PYRAMID_NONE          0
#define X264_B_PYRAMID_STRICT        1
#define X264_B_PYRAMID_NORMAL        2
#define X264_KEYINT_MIN_AUTO         0
#define X264_KEYINT_MAX_INFINITE     (1<<30)

static const char * const x264_direct_pred_names[] = { "none", "spatial", "temporal", "auto", 0 };
static const char * const x264_motion_est_names[] = { "dia", "hex", "umh", "esa", "tesa", 0 };
static const char * const x264_b_pyramid_names[] = { "none", "strict", "normal", 0 };
static const char * const x264_overscan_names[] = { "undef", "show", "crop", 0 };
static const char * const x264_vidformat_names[] = { "component", "pal", "ntsc", "secam", "mac", "undef", 0 };
static const char * const x264_fullrange_names[] = { "off", "on", 0 };
static const char * const x264_colorprim_names[] = { "", "bt709", "undef", "", "bt470m", "bt470bg", "smpte170m", "smpte240m", "film", 0 };
static const char * const x264_transfer_names[] = { "", "bt709", "undef", "", "bt470m", "bt470bg", "smpte170m", "smpte240m", "linear", "log100", "log316", 0 };
static const char * const x264_colmatrix_names[] = { "GBR", "bt709", "undef", "", "fcc", "bt470bg", "smpte170m", "smpte240m", "YCgCo", 0 };
static const char * const x264_nal_hrd_names[] = { "none", "vbr", "cbr", 0 };

/* Colorspace type */
#define X264_CSP_MASK           0x00ff  /* */
#define X264_CSP_NONE           0x0000  /* Invalid mode     */
#define X264_CSP_I420           0x0001  /* yuv 4:2:0 planar */
#define X264_CSP_YV12           0x0002  /* yvu 4:2:0 planar */
#define X264_CSP_NV12           0x0003  /* yuv 4:2:0, with one y plane and one packed u+v */
#define X264_CSP_MAX            0x0004  /* end of list */
#define X264_CSP_VFLIP          0x1000  /* the csp is vertically flipped */
#define X264_CSP_HIGH_DEPTH     0x2000  /* the csp has a depth of 16 bits per pixel component */

/* Slice type */
#define X264_TYPE_AUTO          0x0000  /* Let x264 choose the right type */
#define X264_TYPE_IDR           0x0001
#define X264_TYPE_I             0x0002
#define X264_TYPE_P             0x0003
#define X264_TYPE_BREF          0x0004  /* Non-disposable B-frame */
#define X264_TYPE_B             0x0005
#define X264_TYPE_KEYFRAME      0x0006  /* IDR or I depending on b_open_gop option */
#define IS_X264_TYPE_I(x) ((x)==X264_TYPE_I || (x)==X264_TYPE_IDR)
#define IS_X264_TYPE_B(x) ((x)==X264_TYPE_B || (x)==X264_TYPE_BREF)

/* Log level */
#define X264_LOG_NONE          (-1)
#define X264_LOG_ERROR          0
#define X264_LOG_WARNING        1
#define X264_LOG_INFO           2
#define X264_LOG_DEBUG          3

/* Threading */
#define X264_THREADS_AUTO 0 /* Automatically select optimal number of threads */
#define X264_SYNC_LOOKAHEAD_AUTO (-1) /* Automatically select optimal lookahead thread buffer size */

/* HRD */
#define X264_NAL_HRD_NONE            0
#define X264_NAL_HRD_VBR             1
#define X264_NAL_HRD_CBR             2

/* Zones: override ratecontrol or other options for specific sections of the video.
 * See x264_encoder_reconfig() for which options can be changed.
 * If zones overlap, whichever comes later in the list takes precedence. */
typedef struct
{
    int i_start, i_end; /* range of frame numbers */
    int b_force_qp; /* whether to use qp vs bitrate factor */
    int i_qp;
    float f_bitrate_factor;
    struct x264_param_t *param;
} x264_zone_t;

typedef struct x264_param_t
{
    /* CPU flags */
    unsigned int cpu;
    int         i_threads;       /* encode multiple frames in parallel */
    int         b_sliced_threads;  /* Whether to use slice-based threading. */
    int         b_deterministic; /* whether to allow non-deterministic optimizations when threaded */
    int         i_sync_lookahead; /* threaded lookahead buffer */

    /* Video Properties */
    int         i_width;
    int         i_height;
    int         i_csp;  /* CSP of encoded bitstream, only i420 supported */
    int         i_level_idc;
    int         i_frame_total; /* number of frames to encode if known, else 0 */

    /* NAL HRD
     * Uses Buffering and Picture Timing SEIs to signal HRD
     * The HRD in H.264 was not designed with VFR in mind.
     * It is therefore not recommendeded to use NAL HRD with VFR.
     * Furthermore, reconfiguring the VBV (via x264_encoder_reconfig)
     * will currently generate invalid HRD. */
    int         i_nal_hrd;

    struct
    {
        /* they will be reduced to be 0 < x <= 65535 and prime */
        int         i_sar_height;
        int         i_sar_width;

        int         i_overscan;    /* 0=undef, 1=no overscan, 2=overscan */

        /* see h264 annex E for the values of the following */
        int         i_vidformat;
        int         b_fullrange;
        int         i_colorprim;
        int         i_transfer;
        int         i_colmatrix;
        int         i_chroma_loc;    /* both top & bottom */
    } vui;

    /* Bitstream parameters */
    int         i_frame_reference;  /* Maximum number of reference frames */
    int         i_dpb_size;         /* Force a DPB size larger than that implied by B-frames and reference frames.
                                     * Useful in combination with interactive error resilience. */
    int         i_keyint_max;       /* Force an IDR keyframe at this interval */
    int         i_keyint_min;       /* Scenecuts closer together than this are coded as I, not IDR. */
    int         i_scenecut_threshold; /* how aggressively to insert extra I frames */
    int         b_intra_refresh;    /* Whether or not to use periodic intra refresh instead of IDR frames. */

    int         i_bframe;   /* how many b-frame between 2 references pictures */
    int         i_bframe_adaptive;
    int         i_bframe_bias;
    int         i_bframe_pyramid;   /* Keep some B-frames as references: 0=off, 1=strict hierarchical, 2=normal */
    int         b_open_gop;
    int         b_bluray_compat;

    int         b_deblocking_filter;
    int         i_deblocking_filter_alphac0;    /* [-6, 6] -6 light filter, 6 strong */
    int         i_deblocking_filter_beta;       /* [-6, 6]  idem */

    int         b_cabac;
    int         i_cabac_init_idc;

    int         b_interlaced;
    int         b_constrained_intra;

    int         i_cqm_preset;
    char        *psz_cqm_file;      /* JM format */
    uint8_t     cqm_4iy[16];        /* used only if i_cqm_preset == X264_CQM_CUSTOM */
    uint8_t     cqm_4ic[16];
    uint8_t     cqm_4py[16];
    uint8_t     cqm_4pc[16];
    uint8_t     cqm_8iy[64];
    uint8_t     cqm_8py[64];

    /* Log */
    void        (*pf_log)( void *, int i_level, const char *psz, va_list );
    void        *p_log_private;
    int         i_log_level;
    int         b_visualize;
    char        *psz_dump_yuv;  /* filename for reconstructed frames */

    /* Encoder analyser parameters */
    struct
    {
        unsigned int intra;     /* intra partitions */
        unsigned int inter;     /* inter partitions */

        int          b_transform_8x8;
        int          i_weighted_pred; /* weighting for P-frames */
        int          b_weighted_bipred; /* implicit weighting for B-frames */
        int          i_direct_mv_pred; /* spatial vs temporal mv prediction */
        int          i_chroma_qp_offset;

        int          i_me_method; /* motion estimation algorithm to use (X264_ME_*) */
        int          i_me_range; /* integer pixel motion estimation search range (from predicted mv) */
        int          i_mv_range; /* maximum length of a mv (in pixels). -1 = auto, based on level */
        int          i_mv_range_thread; /* minimum space between threads. -1 = auto, based on number of threads. */
        int          i_subpel_refine; /* subpixel motion estimation quality */
        int          b_chroma_me; /* chroma ME for subpel and mode decision in P-frames */
        int          b_mixed_references; /* allow each mb partition to have its own reference number */
        int          i_trellis;  /* trellis RD quantization */
        int          b_fast_pskip; /* early SKIP detection on P-frames */
        int          b_dct_decimate; /* transform coefficient thresholding on P-frames */
        int          i_noise_reduction; /* adaptive pseudo-deadzone */
        float        f_psy_rd; /* Psy RD strength */
        float        f_psy_trellis; /* Psy trellis strength */
        int          b_psy; /* Toggle all psy optimizations */

        /* the deadzone size that will be used in luma quantization */
        int          i_luma_deadzone[2]; /* {inter, intra} */

        int          b_psnr;    /* compute and print PSNR stats */
        int          b_ssim;    /* compute and print SSIM stats */
    } analyse;

    /* Rate control parameters */
    struct
    {
        int         i_rc_method;    /* X264_RC_* */

        int         i_qp_constant;  /* 0 to (51 + 6*(x264_bit_depth-8)). 0=lossless */
        int         i_qp_min;       /* min allowed QP value */
        int         i_qp_max;       /* max allowed QP value */
        int         i_qp_step;      /* max QP step between frames */

        int         i_bitrate;
        float       f_rf_constant;  /* 1pass VBR, nominal QP */
        float       f_rf_constant_max;  /* In CRF mode, maximum CRF as caused by VBV */
        float       f_rate_tolerance;
        int         i_vbv_max_bitrate;
        int         i_vbv_buffer_size;
        float       f_vbv_buffer_init; /* <=1: fraction of buffer_size. >1: kbit */
        float       f_ip_factor;
        float       f_pb_factor;

        int         i_aq_mode;      /* psy adaptive QP. (X264_AQ_*) */
        float       f_aq_strength;
        int         b_mb_tree;      /* Macroblock-tree ratecontrol. */
        int         i_lookahead;

        /* 2pass */
        int         b_stat_write;   /* Enable stat writing in psz_stat_out */
        char        *psz_stat_out;
        int         b_stat_read;    /* Read stat from psz_stat_in and use it */
        char        *psz_stat_in;

        /* 2pass params (same as ffmpeg ones) */
        float       f_qcompress;    /* 0.0 => cbr, 1.0 => constant qp */
        float       f_qblur;        /* temporally blur quants */
        float       f_complexity_blur; /* temporally blur complexity */
        x264_zone_t *zones;         /* ratecontrol overrides */
        int         i_zones;        /* number of zone_t's */
        char        *psz_zones;     /* alternate method of specifying zones */
    } rc;

    /* Cropping Rectangle parameters: added to those implicitly defined by
       non-mod16 video resolutions. */
    struct
    {
        unsigned int i_left;
        unsigned int i_top;
        unsigned int i_right;
        unsigned int i_bottom;
    } crop_rect;

    /* frame packing arrangement flag */
    int i_frame_packing;

    /* Muxing parameters */
    int b_aud;                  /* generate access unit delimiters */
    int b_repeat_headers;       /* put SPS/PPS before each keyframe */
    int b_annexb;               /* if set, place start codes (4 bytes) before NAL units,
                                 * otherwise place size (4 bytes) before NAL units. */
    int i_sps_id;               /* SPS and PPS id number */
    int b_vfr_input;            /* VFR input.  If 1, use timebase and timestamps for ratecontrol purposes.
                                 * If 0, use fps only. */
    int b_pulldown;             /* use explicity set timebase for CFR */
    uint32_t i_fps_num;
    uint32_t i_fps_den;
    uint32_t i_timebase_num;    /* Timebase numerator */
    uint32_t i_timebase_den;    /* Timebase denominator */

    int b_tff;

    /* Pulldown:
     * The correct pic_struct must be passed with each input frame.
     * The input timebase should be the timebase corresponding to the output framerate. This should be constant.
     * e.g. for 3:2 pulldown timebase should be 1001/30000
     * The PTS passed with each frame must be the PTS of the frame after pulldown is applied.
     * Frame doubling and tripling require b_vfr_input set to zero (see H.264 Table D-1)
     *
     * Pulldown changes are not clearly defined in H.264. Therefore, it is the calling app's responsibility to manage this.
     */

    int b_pic_struct;

    /* Fake Interlaced.
     *
     * Used only when b_interlaced=0. Setting this flag makes it possible to flag the stream as PAFF interlaced yet
     * encode all frames progessively. It is useful for encoding 25p and 30p Blu-Ray streams.
     */

    int b_fake_interlaced;

    /* Slicing parameters */
    int i_slice_max_size;    /* Max size per slice in bytes; includes estimated NAL overhead. */
    int i_slice_max_mbs;     /* Max number of MBs per slice; overrides i_slice_count. */
    int i_slice_count;       /* Number of slices per frame: forces rectangular slices. */

    /* Optional callback for freeing this x264_param_t when it is done being used.
     * Only used when the x264_param_t sits in memory for an indefinite period of time,
     * i.e. when an x264_param_t is passed to x264_t in an x264_picture_t or in zones.
     * Not used when x264_encoder_reconfig is called directly. */
    void (*param_free)( void* );

    /* Optional low-level callback for low-latency encoding.  Called for each output NAL unit
     * immediately after the NAL unit is finished encoding.  This allows the calling application
     * to begin processing video data (e.g. by sending packets over a network) before the frame
     * is done encoding.
     *
     * This callback MUST do the following in order to work correctly:
     * 1) Have available an output buffer of at least size nal->i_payload*3/2 + 5 + 16.
     * 2) Call x264_nal_encode( h, dst, nal ), where dst is the output buffer.
     * After these steps, the content of nal is valid and can be used in the same way as if
     * the NAL unit were output by x264_encoder_encode.
     *
     * This does not need to be synchronous with the encoding process: the data pointed to
     * by nal (both before and after x264_nal_encode) will remain valid until the next
     * x264_encoder_encode call.  The callback must be re-entrant.
     *
     * This callback does not work with frame-based threads; threads must be disabled
     * or sliced-threads enabled.  This callback also does not work as one would expect
     * with HRD -- since the buffering period SEI cannot be calculated until the frame
     * is finished encoding, it will not be sent via this callback.
     *
     * Note also that the NALs are not necessarily returned in order when sliced threads is
     * enabled.  Accordingly, the variable i_first_mb and i_last_mb are available in
     * x264_nal_t to help the calling application reorder the slices if necessary.
     *
     * When this callback is enabled, x264_encoder_encode does not return valid NALs;
     * the calling application is expected to acquire all output NALs through the callback.
     *
     * It is generally sensible to combine this callback with a use of slice-max-mbs or
     * slice-max-size. */
    void (*nalu_process) ( x264_t *h, x264_nal_t *nal );
} x264_param_t;

void x264_nal_encode( x264_t *h, uint8_t *dst, x264_nal_t *nal );

/****************************************************************************
 * H.264 level restriction information
 ****************************************************************************/

typedef struct
{
    int level_idc;
    int mbps;        /* max macroblock processing rate (macroblocks/sec) */
    int frame_size;  /* max frame size (macroblocks) */
    int dpb;         /* max decoded picture buffer (bytes) */
    int bitrate;     /* max bitrate (kbit/sec) */
    int cpb;         /* max vbv buffer (kbit) */
    int mv_range;    /* max vertical mv component range (pixels) */
    int mvs_per_2mb; /* max mvs per 2 consecutive mbs. */
    int slice_rate;  /* ?? */
    int mincr;       /* min compression ratio */
    int bipred8x8;   /* limit bipred to >=8x8 */
    int direct8x8;   /* limit b_direct to >=8x8 */
    int frame_only;  /* forbid interlacing */
} x264_level_t;

/* all of the levels defined in the standard, terminated by .level_idc=0 */
extern const x264_level_t x264_levels[];

/****************************************************************************
 * Basic parameter handling functions
 ****************************************************************************/

/* x264_param_default:
 *      fill x264_param_t with default values and do CPU detection */
void    x264_param_default( x264_param_t * );

/* x264_param_parse:
 *  set one parameter by name.
 *  returns 0 on success, or returns one of the following errors.
 *  note: BAD_VALUE occurs only if it can't even parse the value,
 *  numerical range is not checked until x264_encoder_open() or
 *  x264_encoder_reconfig().
 *  value=NULL means "true" for boolean options, but is a BAD_VALUE for non-booleans. */
#define X264_PARAM_BAD_NAME  (-1)
#define X264_PARAM_BAD_VALUE (-2)
int x264_param_parse( x264_param_t *, const char *name, const char *value );

/****************************************************************************
 * Advanced parameter handling functions
 ****************************************************************************/

/* These functions expose the full power of x264's preset-tune-profile system for
 * easy adjustment of large numbers of internal parameters.
 *
 * In order to replicate x264CLI's option handling, these functions MUST be called
 * in the following order:
 * 1) x264_param_default_preset
 * 2) Custom user options (via param_parse or directly assigned variables)
 * 3) x264_param_apply_fastfirstpass
 * 4) x264_param_apply_profile
 *
 * Additionally, x264CLI does not apply step 3 if the preset chosen is "placebo"
 * or --slow-firstpass is set. */

/* x264_param_default_preset:
 *      The same as x264_param_default, but also use the passed preset and tune
 *      to modify the default settings.
 *      (either can be NULL, which implies no preset or no tune, respectively)
 *
 *      Currently available presets are, ordered from fastest to slowest: */
static const char * const x264_preset_names[] = { "ultrafast", "superfast", "veryfast", "faster", "fast", "medium", "slow", "slower", "veryslow", "placebo", 0 };

/*      The presets can also be indexed numerically, as in:
 *      x264_param_default_preset( &param, "3", ... )
 *      with ultrafast mapping to "0" and placebo mapping to "9".  This mapping may
 *      of course change if new presets are added in between, but will always be
 *      ordered from fastest to slowest.
 *
 *      Warning: the speed of these presets scales dramatically.  Ultrafast is a full
 *      100 times faster than placebo!
 *
 *      Currently available tunings are: */
static const char * const x264_tune_names[] = { "film", "animation", "grain", "stillimage", "psnr", "ssim", "fastdecode", "zerolatency", 0 };

/*      Multiple tunings can be used if separated by a delimiter in ",./-+",
 *      however multiple psy tunings cannot be used.
 *      film, animation, grain, stillimage, psnr, and ssim are psy tunings.
 *
 *      returns 0 on success, negative on failure (e.g. invalid preset/tune name). */
int     x264_param_default_preset( x264_param_t *, const char *preset, const char *tune );

/* x264_param_apply_fastfirstpass:
 *      If first-pass mode is set (rc.b_stat_read == 0, rc.b_stat_write == 1),
 *      modify the encoder settings to disable options generally not useful on
 *      the first pass. */
void    x264_param_apply_fastfirstpass( x264_param_t * );

/* x264_param_apply_profile:
 *      Applies the restrictions of the given profile.
 *      Currently available profiles are, from most to least restrictive: */
static const char * const x264_profile_names[] = { "baseline", "main", "high", "high10", 0 };

/*      (can be NULL, in which case the function will do nothing)
 *
 *      Does NOT guarantee that the given profile will be used: if the restrictions
 *      of "High" are applied to settings that are already Baseline-compatible, the
 *      stream will remain baseline.  In short, it does not increase settings, only
 *      decrease them.
 *
 *      returns 0 on success, negative on failure (e.g. invalid profile name). */
int     x264_param_apply_profile( x264_param_t *, const char *profile );

/****************************************************************************
 * Picture structures and functions
 ****************************************************************************/

/* x264_bit_depth:
 *      Specifies the number of bits per pixel that x264 uses. This is also the
 *      bit depth that x264 encodes in. If this value is > 8, x264 will read
 *      two bytes of input data for each pixel sample, and expect the upper
 *      (16-x264_bit_depth) bits to be zero.
 *      Note: The flag X264_CSP_HIGH_DEPTH must be used to specify the
 *      colorspace depth as well. */
extern const int x264_bit_depth;

enum pic_struct_e
{
    PIC_STRUCT_AUTO              = 0, // automatically decide (default)
    PIC_STRUCT_PROGRESSIVE       = 1, // progressive frame
    // "TOP" and "BOTTOM" are not supported in x264 (PAFF only)
    PIC_STRUCT_TOP_BOTTOM        = 4, // top field followed by bottom
    PIC_STRUCT_BOTTOM_TOP        = 5, // bottom field followed by top
    PIC_STRUCT_TOP_BOTTOM_TOP    = 6, // top field, bottom field, top field repeated
    PIC_STRUCT_BOTTOM_TOP_BOTTOM = 7, // bottom field, top field, bottom field repeated
    PIC_STRUCT_DOUBLE            = 8, // double frame
    PIC_STRUCT_TRIPLE            = 9, // triple frame
};

typedef struct
{
    double cpb_initial_arrival_time;
    double cpb_final_arrival_time;
    double cpb_removal_time;

    double dpb_output_time;
} x264_hrd_t;

/* Arbitrary user SEI:
 * Payload size is in bytes and the payload pointer must be valid.
 * Payload types and syntax can be found in Annex D of the H.264 Specification.
 * SEI payload alignment bits as described in Annex D must be included at the
 * end of the payload if needed.
 * The payload should not be NAL-encapsulated.
 * Payloads are written first in order of input, apart from in the case when HRD
 * is enabled where payloads are written after the Buffering Period SEI. */

typedef struct
{
    int payload_size;
    int payload_type;
    uint8_t *payload;
} x264_sei_payload_t;

typedef struct
{
    int num_payloads;
    x264_sei_payload_t *payloads;
    /* In: optional callback to free each payload AND x264_sei_payload_t when used. */
    void (*sei_free)( void* );
} x264_sei_t;

typedef struct
{
    int     i_csp;       /* Colorspace */
    int     i_plane;     /* Number of image planes */
    int     i_stride[4]; /* Strides for each plane */
    uint8_t *plane[4];   /* Pointers to each plane */
} x264_image_t;

typedef struct
{
    /* In: an array of quantizer offsets to be applied to this image during encoding.
     *     These are added on top of the decisions made by x264.
     *     Offsets can be fractional; they are added before QPs are rounded to integer.
     *     Adaptive quantization must be enabled to use this feature.  Behavior if quant
     *     offsets differ between encoding passes is undefined.
     *
     *     Array contains one offset per macroblock, in raster scan order.  In interlaced
     *     mode, top-field MBs and bottom-field MBs are interleaved at the row level. */
    float *quant_offsets;
    /* In: optional callback to free quant_offsets when used.
     *     Useful if one wants to use a different quant_offset array for each frame. */
    void (*quant_offsets_free)( void* );
} x264_image_properties_t;

typedef struct
{
    /* In: force picture type (if not auto)
     *     If x264 encoding parameters are violated in the forcing of picture types,
     *     x264 will correct the input picture type and log a warning.
     *     The quality of frametype decisions may suffer if a great deal of fine-grained
     *     mixing of auto and forced frametypes is done.
     * Out: type of the picture encoded */
    int     i_type;
    /* In: force quantizer for != X264_QP_AUTO */
    int     i_qpplus1;
    /* In: pic_struct, for pulldown/doubling/etc...used only if b_pic_struct=1.
     *     use pic_struct_e for pic_struct inputs
     * Out: pic_struct element associated with frame */
    int     i_pic_struct;
    /* Out: whether this frame is a keyframe.  Important when using modes that result in
     * SEI recovery points being used instead of IDR frames. */
    int     b_keyframe;
    /* In: user pts, Out: pts of encoded picture (user)*/
    int64_t i_pts;
    /* Out: frame dts. When the pts of the first frame is close to zero,
     *      initial frames may have a negative dts which must be dealt with by any muxer */
    int64_t i_dts;
    /* In: custom encoding parameters to be set from this frame forwards
           (in coded order, not display order). If NULL, continue using
           parameters from the previous frame.  Some parameters, such as
           aspect ratio, can only be changed per-GOP due to the limitations
           of H.264 itself; in this case, the caller must force an IDR frame
           if it needs the changed parameter to apply immediately. */
    x264_param_t *param;
    /* In: raw data */
    x264_image_t img;
    /* In: optional information to modify encoder decisions for this frame */
    x264_image_properties_t prop;
    /* Out: HRD timing information. Output only when i_nal_hrd is set. */
    x264_hrd_t hrd_timing;
    /* In: arbitrary user SEI (e.g subtitles, AFDs) */
    x264_sei_t extra_sei;
    /* private user data. libx264 doesn't touch this,
       not even copy it from input to output frames. */
    void *opaque;
} x264_picture_t;

/* x264_picture_init:
 *  initialize an x264_picture_t.  Needs to be done if the calling application
 *  allocates its own x264_picture_t as opposed to using x264_picture_alloc. */
void x264_picture_init( x264_picture_t *pic );

/* x264_picture_alloc:
 *  alloc data for a picture. You must call x264_picture_clean on it.
 *  returns 0 on success, or -1 on malloc failure or invalid colorspace. */
int x264_picture_alloc( x264_picture_t *pic, int i_csp, int i_width, int i_height );

/* x264_picture_clean:
 *  free associated resource for a x264_picture_t allocated with
 *  x264_picture_alloc ONLY */
void x264_picture_clean( x264_picture_t *pic );

/****************************************************************************
 * Encoder functions
 ****************************************************************************/

/* Force a link error in the case of linking against an incompatible API version.
 * Glue #defines exist to force correct macro expansion; the final output of the macro
 * is x264_encoder_open_##X264_BUILD (for purposes of dlopen). */
#define x264_encoder_glue1(x,y) x##y
#define x264_encoder_glue2(x,y) x264_encoder_glue1(x,y)
#define x264_encoder_open x264_encoder_glue2(x264_encoder_open_,X264_BUILD)

/* x264_encoder_open:
 *      create a new encoder handler, all parameters from x264_param_t are copied */
x264_t *x264_encoder_open( x264_param_t * );

/* x264_encoder_reconfig:
 *      various parameters from x264_param_t are copied.
 *      this takes effect immediately, on whichever frame is encoded next;
 *      due to delay, this may not be the next frame passed to encoder_encode.
 *      if the change should apply to some particular frame, use x264_picture_t->param instead.
 *      returns 0 on success, negative on parameter validation error.
 *      not all parameters can be changed; see the actual function for a detailed breakdown. */
int     x264_encoder_reconfig( x264_t *, x264_param_t * );
/* x264_encoder_parameters:
 *      copies the current internal set of parameters to the pointer provided
 *      by the caller.  useful when the calling application needs to know
 *      how x264_encoder_open has changed the parameters, or the current state
 *      of the encoder after multiple x264_encoder_reconfig calls.
 *      note that the data accessible through pointers in the returned param struct
 *      (e.g. filenames) should not be modified by the calling application. */
void    x264_encoder_parameters( x264_t *, x264_param_t * );
/* x264_encoder_headers:
 *      return the SPS and PPS that will be used for the whole stream.
 *      *pi_nal is the number of NAL units outputted in pp_nal.
 *      returns negative on error.
 *      the payloads of all output NALs are guaranteed to be sequential in memory. */
int     x264_encoder_headers( x264_t *, x264_nal_t **pp_nal, int *pi_nal );
/* x264_encoder_encode:
 *      encode one picture.
 *      *pi_nal is the number of NAL units outputted in pp_nal.
 *      returns negative on error, zero if no NAL units returned.
 *      the payloads of all output NALs are guaranteed to be sequential in memory. */
int     x264_encoder_encode( x264_t *, x264_nal_t **pp_nal, int *pi_nal, x264_picture_t *pic_in, x264_picture_t *pic_out );
/* x264_encoder_close:
 *      close an encoder handler */
void    x264_encoder_close  ( x264_t * );
/* x264_encoder_delayed_frames:
 *      return the number of currently delayed (buffered) frames
 *      this should be used at the end of the stream, to know when you have all the encoded frames. */
int     x264_encoder_delayed_frames( x264_t * );
/* x264_encoder_maximum_delayed_frames( x264_t *h ):
 *      return the maximum number of delayed (buffered) frames that can occur with the current
 *      parameters. */
int     x264_encoder_maximum_delayed_frames( x264_t *h );
/* x264_encoder_intra_refresh:
 *      If an intra refresh is not in progress, begin one with the next P-frame.
 *      If an intra refresh is in progress, begin one as soon as the current one finishes.
 *      Requires that b_intra_refresh be set.
 *
 *      Useful for interactive streaming where the client can tell the server that packet loss has
 *      occurred.  In this case, keyint can be set to an extremely high value so that intra refreshes
 *      only occur when calling x264_encoder_intra_refresh.
 *
 *      In multi-pass encoding, if x264_encoder_intra_refresh is called differently in each pass,
 *      behavior is undefined.
 *
 *      Should not be called during an x264_encoder_encode. */
void    x264_encoder_intra_refresh( x264_t * );
/* x264_encoder_invalidate_reference:
 *      An interactive error resilience tool, designed for use in a low-latency one-encoder-few-clients
 *      system.  When the client has packet loss or otherwise incorrectly decodes a frame, the encoder
 *      can be told with this command to "forget" the frame and all frames that depend on it, referencing
 *      only frames that occurred before the loss.  This will force a keyframe if no frames are left to
 *      reference after the aforementioned "forgetting".
 *
 *      It is strongly recommended to use a large i_dpb_size in this case, which allows the encoder to
 *      keep around extra, older frames to fall back on in case more recent frames are all invalidated.
 *      Unlike increasing i_frame_reference, this does not increase the number of frames used for motion
 *      estimation and thus has no speed impact.  It is also recommended to set a very large keyframe
 *      interval, so that keyframes are not used except as necessary for error recovery.
 *
 *      x264_encoder_invalidate_reference is not currently compatible with the use of B-frames or intra
 *      refresh.
 *
 *      In multi-pass encoding, if x264_encoder_invalidate_reference is called differently in each pass,
 *      behavior is undefined.
 *
 *      Should not be called during an x264_encoder_encode, but multiple calls can be made simultaneously.
 *
 *      Returns 0 on success, negative on failure. */
int x264_encoder_invalidate_reference( x264_t *, int64_t pts );

#endif