vf_gainmap.c File Reference

Filter to compute an HDR gain map from a base and alternate rendition. More...

#include <float.h>
#include <math.h>
#include "libavutil/csp.h"
#include "libavutil/gain_map.h"
#include "libavutil/internal.h"
#include "libavutil/mastering_display_metadata.h"
#include "libavutil/mem.h"
#include "libavutil/opt.h"
#include "libavutil/pixdesc.h"
#include "avfilter.h"
#include "colorspace.h"
#include "filters.h"
#include "formats.h"
#include "framesync.h"
#include "video.h"

Go to the source code of this file.

Data Structures
struct	GainMapEOTF
struct	GainMapContext
struct	ThreadData
	Used for passing data between threads. More...

Macros
#define	SDR_DIFFUSE_WHITE   203.0
#define	GAINMAP_LUT_SIZE   1025
#define	OFFSET(x)
#define	FLAGS   AV_OPT_FLAG_FILTERING_PARAM | AV_OPT_FLAG_VIDEO_PARAM
#define	GAIN(a, b)

Enumerations
enum	GainMapColorspace { GAINMAP_CSP_BASE , GAINMAP_CSP_ALT , GAINMAP_CSP_NB }
enum	GainMapMode { GAINMAP_RGB , GAINMAP_LUMA , GAINMAP_MAXRGB , GAINMAP_MODE_NB }
enum	GainMapMeasure {   MEASURE_MIN = 1 << 0 , MEASURE_MAX = 1 << 1 , MEASURE_GAMMA = 1 << 2 , MEASURE_RANGE = MEASURE_MIN | MEASURE_MAX ,   MEASURE_ALL = MEASURE_RANGE | MEASURE_GAMMA }

Functions
	FRAMESYNC_DEFINE_CLASS (gainmap, GainMapContext, fs)
static AVRational	quantq (double x, enum AVRounding rnd)
static void	setup_range (AVFilterContext *ctx, int ch, AVRational min, AVRational max)
static void	setup_gamma (AVFilterContext *ctx, int ch, AVRational gamma)
static av_cold int	init (AVFilterContext *ctx)
static int	query_formats (const AVFilterContext *ctx, AVFilterFormatsConfig **cfg_in, AVFilterFormatsConfig **cfg_out)
static double	frame_luminance (const AVFrame *frame)
static void	update_eotf (GainMapEOTF *tf, enum AVColorTransferCharacteristic trc, av_csp_eotf_function eotf, double Lw)
static const char *	unknown_if_null (const char *s)
static int	setup_colorspace (AVFilterContext *ctx, const AVFrame *base, const AVFrame *alt)
static av_always_inline float	quantize (float gain, float scale, float offset, float gamma)
static av_always_inline void	get_pixel (const GainMapContext *s, float dst[3], const float *restrict const src[3], int x, int alt)
static av_always_inline int	slice_internal (AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs, int quant)
static int	slice_gain (AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
static int	slice_gain_quant (AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
static int	slice_quant (AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
static void	choose_quant_params (AVFilterContext *ctx, const AVFrame *out, int nb_jobs)
static int	process_frame (FFFrameSync *fs)
static int	config_output (AVFilterLink *outlink)
static int	activate (AVFilterContext *ctx)
static av_cold void	uninit (AVFilterContext *ctx)

Variables
static const AVOption	gainmap_options []
static const int	gbr_order [3] = { 2, 0, 1 }
static const AVFilterPad	gainmap_inputs []
static const AVFilterPad	gainmap_outputs []
const FFFilter	ff_vf_gainmap

Detailed Description

Filter to compute an HDR gain map from a base and alternate rendition.

Definition in file vf_gainmap.c.

Macro Definition Documentation

SDR_DIFFUSE_WHITE

#define SDR_DIFFUSE_WHITE   203.0

Definition at line 42 of file vf_gainmap.c.

Referenced by frame_luminance(), get_pixel(), setup_colorspace(), and update_eotf().

GAINMAP_LUT_SIZE

#define GAINMAP_LUT_SIZE   1025

Definition at line 70 of file vf_gainmap.c.

Referenced by get_pixel(), and update_eotf().

OFFSET

#define OFFSET

(

x

)

Value:

offsetof(GainMapContext, x)

Definition at line 121 of file vf_gainmap.c.

FLAGS

#define FLAGS   AV_OPT_FLAG_FILTERING_PARAM | AV_OPT_FLAG_VIDEO_PARAM

Definition at line 122 of file vf_gainmap.c.

GAIN

#define GAIN	(		a,
			b )

Value:

(sign * log2f(((a) + alt_off) / ((b) + base_off)))

Referenced by slice_internal().

Enumeration Type Documentation

GainMapColorspace

enum GainMapColorspace

Enumerator
GAINMAP_CSP_BASE	apply the map in the base rendition's space
GAINMAP_CSP_ALT	apply it in the alternate rendition's space
GAINMAP_CSP_NB

Definition at line 44 of file vf_gainmap.c.

GainMapMode

enum GainMapMode

Enumerator
GAINMAP_RGB	one channel per component
GAINMAP_LUMA	single channel, from the luminance
GAINMAP_MAXRGB	single channel, from max(R,G,B)
GAINMAP_MODE_NB

Definition at line 50 of file vf_gainmap.c.

GainMapMeasure

enum GainMapMeasure

Enumerator
MEASURE_MIN
MEASURE_MAX
MEASURE_GAMMA
MEASURE_RANGE
MEASURE_ALL

Definition at line 57 of file vf_gainmap.c.

Function Documentation

FRAMESYNC_DEFINE_CLASS()

FRAMESYNC_DEFINE_CLASS	(	gainmap	,
		GainMapContext	,
		fs	)

quantq()

static AVRational quantq ( double x, enum AVRounding rnd )

static

Definition at line 145 of file vf_gainmap.c.

Referenced by choose_quant_params(), and setup_colorspace().

setup_range()

static void setup_range ( AVFilterContext * ctx, int ch, AVRational min, AVRational max )

static

Definition at line 161 of file vf_gainmap.c.

Referenced by choose_quant_params(), init(), and setup_colorspace().

setup_gamma()

static void setup_gamma ( AVFilterContext * ctx, int ch, AVRational gamma )

static

Definition at line 180 of file vf_gainmap.c.

Referenced by choose_quant_params(), init(), and setup_colorspace().

init()

static av_cold int init ( AVFilterContext * ctx )

static

Definition at line 189 of file vf_gainmap.c.

query_formats()

static int query_formats ( const AVFilterContext * ctx, AVFilterFormatsConfig ** cfg_in, AVFilterFormatsConfig ** cfg_out )

static

Definition at line 231 of file vf_gainmap.c.

frame_luminance()

static double frame_luminance ( const AVFrame * frame )

static

Definition at line 250 of file vf_gainmap.c.

Referenced by setup_colorspace().

update_eotf()

static void update_eotf ( GainMapEOTF * tf, enum AVColorTransferCharacteristic trc, av_csp_eotf_function eotf, double Lw )

static

Definition at line 268 of file vf_gainmap.c.

Referenced by setup_colorspace().

unknown_if_null()

static const char * unknown_if_null ( const char * s )

static

Definition at line 309 of file vf_gainmap.c.

Referenced by setup_colorspace().

setup_colorspace()

static int setup_colorspace ( AVFilterContext * ctx, const AVFrame * base, const AVFrame * alt )

static

Definition at line 315 of file vf_gainmap.c.

Referenced by process_frame().

quantize()

static av_always_inline float quantize ( float gain, float scale, float offset, float gamma )

static

Definition at line 392 of file vf_gainmap.c.

Referenced by slice_internal(), and slice_quant().

get_pixel()

static av_always_inline void get_pixel ( const GainMapContext * s, float dst[3], const float *restrict const src[3], int x, int alt )

static

Definition at line 399 of file vf_gainmap.c.

Referenced by slice_internal().

slice_internal()

static av_always_inline int slice_internal ( AVFilterContext * ctx, void * arg, int jobnr, int nb_jobs, int quant )

static

Definition at line 439 of file vf_gainmap.c.

Referenced by slice_gain(), and slice_gain_quant().

slice_gain()

static int slice_gain ( AVFilterContext * ctx, void * arg, int jobnr, int nb_jobs )

static

Definition at line 529 of file vf_gainmap.c.

Referenced by process_frame().

slice_gain_quant()

static int slice_gain_quant ( AVFilterContext * ctx, void * arg, int jobnr, int nb_jobs )

static

Definition at line 534 of file vf_gainmap.c.

Referenced by process_frame().

slice_quant()

static int slice_quant ( AVFilterContext * ctx, void * arg, int jobnr, int nb_jobs )

static

Definition at line 539 of file vf_gainmap.c.

Referenced by process_frame().

choose_quant_params()

static void choose_quant_params ( AVFilterContext * ctx, const AVFrame * out, int nb_jobs )

static

Choose gamma such that mean_quant ^ gamma = 0.5; clamp to a sane value range of [1/8, 8] to prevent degenerate encodings. A gamma of >8 would collapse half the encoding space into a single 8-bit value, at which point we're losing more then gaining, and a value of <1/8 limits the amount by which a single high outlier pixel can determine the overall encoding gamma.

We also clamp the mean to [0.01, 0.99] to prevent numerical explosion in the case that the mean is very close to 0 or 1. This is a looser bound than the final gamma clamp, so the exact values chosen do not matter as much.

Definition at line 570 of file vf_gainmap.c.

Referenced by process_frame().

process_frame()

static int process_frame ( FFFrameSync * fs )

static

Definition at line 619 of file vf_gainmap.c.

config_output()

static int config_output ( AVFilterLink * outlink )

static

Definition at line 692 of file vf_gainmap.c.

activate()

static int activate ( AVFilterContext * ctx )

static

Definition at line 727 of file vf_gainmap.c.

uninit()

static av_cold void uninit ( AVFilterContext * ctx )

static

Definition at line 733 of file vf_gainmap.c.

Variable Documentation

gainmap_options

const AVOption gainmap_options[]

static

Initial value:

= {
    { "mode", "quantity the gain is computed over", OFFSET(mode), AV_OPT_TYPE_INT, { .i64 = GAINMAP_RGB }, 0, GAINMAP_MODE_NB - 1, FLAGS, .unit = "mode" },
        { "rgb",    "one gain channel per component",       0, AV_OPT_TYPE_CONST, { .i64 = GAINMAP_RGB },    0, 0, FLAGS, .unit = "mode" },
        { "luma",   "single gain channel, from luminance",  0, AV_OPT_TYPE_CONST, { .i64 = GAINMAP_LUMA },   0, 0, FLAGS, .unit = "mode" },
        { "maxrgb", "single gain channel, from max(R,G,B)", 0, AV_OPT_TYPE_CONST, { .i64 = GAINMAP_MAXRGB }, 0, 0, FLAGS, .unit = "mode" },
    { "colorspace", "rendition whose colour space the map is applied in", OFFSET(colorspace), AV_OPT_TYPE_INT, { .i64 = GAINMAP_CSP_BASE }, 0, GAINMAP_CSP_NB - 1, FLAGS, .unit = "colorspace" },
        { "base",      "the base rendition's colour space",             0, AV_OPT_TYPE_CONST, { .i64 = GAINMAP_CSP_BASE   }, 0, 0, FLAGS, .unit = "colorspace" },
        { "alternate", "the alternate rendition's colour space",        0, AV_OPT_TYPE_CONST, { .i64 = GAINMAP_CSP_ALT    }, 0, 0, FLAGS, .unit = "colorspace" },
    { "min", "override lower bound on the encoded gain, in log2 space", OFFSET(gain_min), AV_OPT_TYPE_RATIONAL, { .dbl = NAN }, -32.0, 32.0, FLAGS },
    { "max", "override upper bound on the encoded gain, in log2 space", OFFSET(gain_max), AV_OPT_TYPE_RATIONAL, { .dbl = NAN }, -32.0, 32.0, FLAGS },
    { "gamma", "override encoding gamma of the stored map (default: measured)", OFFSET(gamma), AV_OPT_TYPE_RATIONAL, { .dbl = NAN }, 0.0001, 100.0, FLAGS },
    { "base_offset", "constant added to the base rendition", OFFSET(base_offset), AV_OPT_TYPE_RATIONAL, { .dbl = 1.0 / 64.0 }, 1e-6, 1.0, FLAGS },
    { "alt_offset", "constant added to the alternate rendition", OFFSET(alt_offset), AV_OPT_TYPE_RATIONAL, { .dbl = 1.0 / 64.0 }, 1e-6, 1.0, FLAGS },
    { "base_nits", "override input luminance of the base rendition", OFFSET(base_nits), AV_OPT_TYPE_RATIONAL, { .dbl = NAN }, 1.0, 10000.0, FLAGS },
    { "alt_nits", "override input luminance of the alternate rendition", OFFSET(alt_nits), AV_OPT_TYPE_RATIONAL, { .dbl = NAN }, 1.0, 10000.0, FLAGS },
    { NULL }
}

Definition at line 124 of file vf_gainmap.c.

gbr_order

const int gbr_order[3] = { 2, 0, 1 }

static

Definition at line 436 of file vf_gainmap.c.

gainmap_inputs

const AVFilterPad gainmap_inputs[]

static

Initial value:

= {
    {
        .name = "base",
        .type = AVMEDIA_TYPE_VIDEO,
    },
    {
        .name = "alternate",
        .type = AVMEDIA_TYPE_VIDEO,
    },
}

Definition at line 742 of file vf_gainmap.c.

gainmap_outputs

const AVFilterPad gainmap_outputs[]

static

Initial value:

= {
    {
        .name         = "default",
        .type         = AVMEDIA_TYPE_VIDEO,
        .config_props = config_output,
    },
}

Definition at line 753 of file vf_gainmap.c.

ff_vf_gainmap

const FFFilter ff_vf_gainmap

Initial value:

= {
    .p.name        = "gainmap",
    .p.description = NULL_IF_CONFIG_SMALL("Generate a gain map from a base/alternate pair."),
    .p.priv_class  = &gainmap_class,
    .p.flags       = AVFILTER_FLAG_SLICE_THREADS,
    .preinit       = gainmap_framesync_preinit,
    .priv_size     = sizeof(GainMapContext),
    .init          = init,
    .uninit        = uninit,
    .activate      = activate,
    FILTER_INPUTS(gainmap_inputs),
    FILTER_OUTPUTS(gainmap_outputs),
    FILTER_QUERY_FUNC2(query_formats),
}

Definition at line 761 of file vf_gainmap.c.