vf_thumbnail.c File Reference

#include "libavutil/intreadwrite.h"
#include "libavutil/mem.h"
#include "libavutil/opt.h"
#include "libavutil/pixdesc.h"
#include "avfilter.h"
#include "filters.h"
#include "formats.h"

Go to the source code of this file.

Data Structures
struct	thumb_frame
struct	ThumbContext

Macros
#define	HIST_SIZE   (3*256)
#define	OFFSET(x)   offsetof(ThumbContext, x)
#define	FLAGS   AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM

Functions
	AVFILTER_DEFINE_CLASS (thumbnail)
static av_cold int	init (AVFilterContext *ctx)
static double	frame_sum_square_err (const int *hist, const double *median)
	Compute Sum-square deviation to estimate "closeness". More...
static AVFrame *	get_best_frame (AVFilterContext *ctx)
static void	get_hist8 (int *hist, const uint8_t *p, ptrdiff_t stride, ptrdiff_t width, ptrdiff_t height)
static void	get_hist16 (int *hist, const uint8_t *p, ptrdiff_t stride, ptrdiff_t width, ptrdiff_t height, int shift)
static int	do_slice (AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
static int	filter_frame (AVFilterLink *inlink, AVFrame *frame)
static av_cold void	uninit (AVFilterContext *ctx)
static int	request_frame (AVFilterLink *link)
static int	config_props (AVFilterLink *inlink)
static int	query_formats (const AVFilterContext *ctx, AVFilterFormatsConfig **cfg_in, AVFilterFormatsConfig **cfg_out)

Variables
static const AVOption	thumbnail_options []
static enum AVPixelFormat	packed_rgb_fmts []
static const AVFilterPad	thumbnail_inputs []
static const AVFilterPad	thumbnail_outputs []
const FFFilter	ff_vf_thumbnail

Detailed Description

Potential thumbnail lookup filter to reduce the risk of an inappropriate selection (such as a black frame) we could get with an absolute seek.

Simplified version of algorithm by Vadim Zaliva lord@.nosp@m.croc.nosp@m.odile.nosp@m..org.

See also

http://notbrainsurgery.livejournal.com/29773.html

Definition in file vf_thumbnail.c.

Macro Definition Documentation

HIST_SIZE

#define HIST_SIZE   (3*256)

Definition at line 38 of file vf_thumbnail.c.

OFFSET

#define OFFSET

(

x

)

offsetof(ThumbContext, x)

Definition at line 62 of file vf_thumbnail.c.

FLAGS

#define FLAGS   AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM

Definition at line 63 of file vf_thumbnail.c.

Function Documentation

AVFILTER_DEFINE_CLASS()

AVFILTER_DEFINE_CLASS

(

thumbnail

)

init()

static av_cold int init ( AVFilterContext *  ctx )

static

Definition at line 76 of file vf_thumbnail.c.

frame_sum_square_err()

static double frame_sum_square_err ( const int *  hist, const double *  median  )

static

Compute Sum-square deviation to estimate "closeness".

Parameters

hist	color distribution histogram
median	average color distribution histogram

Returns

sum of squared errors

Definition at line 96 of file vf_thumbnail.c.

Referenced by get_best_frame().

get_best_frame()

static AVFrame* get_best_frame ( AVFilterContext *  ctx )

static

Definition at line 108 of file vf_thumbnail.c.

Referenced by filter_frame(), and request_frame().

get_hist8()

static void get_hist8 ( int *  hist, const uint8_t *  p, ptrdiff_t  stride, ptrdiff_t  width, ptrdiff_t  height  )

static

Definition at line 149 of file vf_thumbnail.c.

Referenced by do_slice().

get_hist16()

static void get_hist16 ( int *  hist, const uint8_t *  p, ptrdiff_t  stride, ptrdiff_t  width, ptrdiff_t  height, int  shift  )

static

Definition at line 175 of file vf_thumbnail.c.

Referenced by do_slice().

do_slice()

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

static

Definition at line 202 of file vf_thumbnail.c.

Referenced by filter_frame().

filter_frame()

static int filter_frame ( AVFilterLink *  inlink, AVFrame *  frame  )

static

Definition at line 274 of file vf_thumbnail.c.

uninit()

static av_cold void uninit ( AVFilterContext *  ctx )

static

Definition at line 303 of file vf_thumbnail.c.

request_frame()

static int request_frame ( AVFilterLink *  link )

static

Definition at line 313 of file vf_thumbnail.c.

config_props()

static int config_props ( AVFilterLink *  inlink )

static

Definition at line 330 of file vf_thumbnail.c.

query_formats()

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

static

Definition at line 361 of file vf_thumbnail.c.

Variable Documentation

thumbnail_options

const AVOption thumbnail_options[]

static

Initial value:

= {
    { "n", "set the frames batch size", OFFSET(n_frames), AV_OPT_TYPE_INT, {.i64=100}, 2, INT_MAX, FLAGS },
    { "log", "force stats logging level", OFFSET(loglevel), AV_OPT_TYPE_INT, {.i64 = AV_LOG_INFO}, INT_MIN, INT_MAX, FLAGS, .unit = "level" },
        { "quiet",   "logging disabled",          0, AV_OPT_TYPE_CONST, {.i64 = AV_LOG_QUIET},   0, 0, FLAGS, .unit = "level" },
        { "info",    "information logging level", 0, AV_OPT_TYPE_CONST, {.i64 = AV_LOG_INFO},    0, 0, FLAGS, .unit = "level" },
        { "verbose", "verbose logging level",     0, AV_OPT_TYPE_CONST, {.i64 = AV_LOG_VERBOSE}, 0, 0, FLAGS, .unit = "level" },
    { NULL }
}

Definition at line 65 of file vf_thumbnail.c.

packed_rgb_fmts

enum AVPixelFormat packed_rgb_fmts[]

static

Initial value:

= {
    AV_PIX_FMT_RGB24, AV_PIX_FMT_BGR24,
    AV_PIX_FMT_RGBA,  AV_PIX_FMT_BGRA,
    AV_PIX_FMT_RGB0,  AV_PIX_FMT_BGR0,
    AV_PIX_FMT_ABGR,  AV_PIX_FMT_ARGB,
    AV_PIX_FMT_0BGR,  AV_PIX_FMT_0RGB,
    AV_PIX_FMT_NONE
}

Definition at line 352 of file vf_thumbnail.c.

Referenced by query_formats().

thumbnail_inputs

const AVFilterPad thumbnail_inputs[]

static

Initial value:

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

Definition at line 390 of file vf_thumbnail.c.

thumbnail_outputs

const AVFilterPad thumbnail_outputs[]

static

Initial value:

= {
    {
        .name          = "default",
        .type          = AVMEDIA_TYPE_VIDEO,
        .request_frame = request_frame,
    },
}

Definition at line 399 of file vf_thumbnail.c.

ff_vf_thumbnail

const FFFilter ff_vf_thumbnail

Initial value:

= {
    .p.name        = "thumbnail",
    .p.description = NULL_IF_CONFIG_SMALL("Select the most representative frame in a given sequence of consecutive frames."),
    .p.priv_class  = &thumbnail_class,
    .p.flags       = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC |
                     AVFILTER_FLAG_SLICE_THREADS,
    .priv_size     = sizeof(ThumbContext),
    .init          = init,
    .uninit        = uninit,
    FILTER_INPUTS(thumbnail_inputs),
    FILTER_OUTPUTS(thumbnail_outputs),
    FILTER_QUERY_FUNC2(query_formats),
}

Definition at line 407 of file vf_thumbnail.c.