vf_readeia608.c File Reference

Filter for reading closed captioning data (EIA-608). More...

#include <string.h>
#include "libavutil/internal.h"
#include "libavutil/mem.h"
#include "libavutil/opt.h"
#include "libavutil/pixdesc.h"
#include "avfilter.h"
#include "filters.h"
#include "video.h"

Go to the source code of this file.

Data Structures
struct	LineItem
struct	CodeItem
struct	ScanItem
struct	ReadEIA608Context

Macros
#define	LAG   25
#define	CLOCK_BITSIZE_MIN   0.2f
#define	CLOCK_BITSIZE_MAX   1.5f
#define	SYNC_BITSIZE_MIN   12.f
#define	SYNC_BITSIZE_MAX   15.f
#define	OFFSET(x)
#define	FLAGS   AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_RUNTIME_PARAM
#define	READ_LINE(type, name)

Functions
	AVFILTER_DEFINE_CLASS (readeia608)
static int	config_filter (AVFilterContext *ctx, int start, int end)
static void	build_histogram (ReadEIA608Context *s, ScanItem *scan, const LineItem *line, int len)
static void	find_black_and_white (ReadEIA608Context *s, ScanItem *scan)
static float	meanf (const LineItem *line, int len)
static float	stddevf (const LineItem *line, int len)
static void	thresholding (ReadEIA608Context *s, ScanItem *scan, LineItem *line, int lag, float threshold, float influence, int len)
static int	periods (const LineItem *line, CodeItem *code, int len)
static void	dump_code (AVFilterContext *ctx, ScanItem *scan, int len, int item)
static int	config_input (AVFilterLink *inlink)
static void	extract_line (AVFilterContext *ctx, AVFrame *in, ScanItem *scan, int w, int nb_line)
static int	extract_lines (AVFilterContext *ctx, void *arg, int job, int nb_jobs)
static int	filter_frame (AVFilterLink *inlink, AVFrame *in)
static av_cold void	uninit (AVFilterContext *ctx)
static int	process_command (AVFilterContext *ctx, const char *cmd, const char *args, char *res, int res_len, int flags)

Variables
static const AVOption	readeia608_options []
static enum AVPixelFormat	pixel_fmts []
static const AVFilterPad	readeia608_inputs []
const FFFilter	ff_vf_readeia608

Detailed Description

Filter for reading closed captioning data (EIA-608).

See also https://en.wikipedia.org/wiki/EIA-608

Definition in file vf_readeia608.c.

Macro Definition Documentation

LAG

#define LAG   25

Definition at line 38 of file vf_readeia608.c.

Referenced by build_histogram(), config_filter(), extract_line(), and periods().

CLOCK_BITSIZE_MIN

#define CLOCK_BITSIZE_MIN   0.2f

Definition at line 39 of file vf_readeia608.c.

Referenced by extract_line().

CLOCK_BITSIZE_MAX

#define CLOCK_BITSIZE_MAX   1.5f

Definition at line 40 of file vf_readeia608.c.

Referenced by extract_line().

SYNC_BITSIZE_MIN

#define SYNC_BITSIZE_MIN   12.f

Definition at line 41 of file vf_readeia608.c.

Referenced by extract_line().

SYNC_BITSIZE_MAX

#define SYNC_BITSIZE_MAX   15.f

Definition at line 42 of file vf_readeia608.c.

Referenced by extract_line().

OFFSET

#define OFFSET

(

x

)

Value:

offsetof(ReadEIA608Context, x)

Definition at line 88 of file vf_readeia608.c.

FLAGS

#define FLAGS   AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_RUNTIME_PARAM

Definition at line 89 of file vf_readeia608.c.

READ_LINE

#define READ_LINE	(		type,
			name )

Value:

static void read_##name(AVFrame *in, int nb_line, LineItem *line, int lp, int w) \
{                                                                             \
    const type *src = (const type *)(&in->data[0][nb_line * in->linesize[0]]);\
                                                                              \
    if (lp) {                                                                 \
        for (int i = 0; i < w; i++) {                                         \
            int a = FFMAX(i - 3, 0);                                          \
            int b = FFMAX(i - 2, 0);                                          \
            int c = FFMAX(i - 1, 0);                                          \
            int d = FFMIN(i + 3, w-1);                                        \
            int e = FFMIN(i + 2, w-1);                                        \
            int f = FFMIN(i + 1, w-1);                                        \
                                                                              \
            line[LAG + i].input = (src[a] + src[b] + src[c] + src[i] +        \
                                   src[d] + src[e] + src[f] + 6) / 7;         \
        }                                                                     \
    } else {                                                                  \
        for (int i = 0; i < w; i++) {                                         \
            line[LAG + i].input = src[i];                                     \
        }                                                                     \
    }                                                                         \
}

Definition at line 316 of file vf_readeia608.c.

Function Documentation

AVFILTER_DEFINE_CLASS()

AVFILTER_DEFINE_CLASS

(

readeia608

)

config_filter()

static int config_filter ( AVFilterContext * ctx, int start, int end )

static

Definition at line 126 of file vf_readeia608.c.

Referenced by config_input(), and process_command().

build_histogram()

static void build_histogram ( ReadEIA608Context * s, ScanItem * scan, const LineItem * line, int len )

static

Definition at line 171 of file vf_readeia608.c.

Referenced by extract_line().

find_black_and_white()

static void find_black_and_white ( ReadEIA608Context * s, ScanItem * scan )

static

Definition at line 179 of file vf_readeia608.c.

Referenced by extract_line().

meanf()

static float meanf ( const LineItem * line, int len )

static

Definition at line 222 of file vf_readeia608.c.

Referenced by stddevf(), and thresholding().

stddevf()

static float stddevf ( const LineItem * line, int len )

static

Definition at line 234 of file vf_readeia608.c.

Referenced by thresholding().

thresholding()

static void thresholding ( ReadEIA608Context * s, ScanItem * scan, LineItem * line, int lag, float threshold, float influence, int len )

static

Definition at line 245 of file vf_readeia608.c.

Referenced by extract_line().

periods()

static int periods ( const LineItem * line, CodeItem * code, int len )

static

Definition at line 284 of file vf_readeia608.c.

Referenced by extract_line().

dump_code()

static void dump_code ( AVFilterContext * ctx, ScanItem * scan, int len, int item )

static

Definition at line 307 of file vf_readeia608.c.

Referenced by extract_line().

config_input()

static int config_input ( AVFilterLink * inlink )

static

Definition at line 343 of file vf_readeia608.c.

extract_line()

static void extract_line ( AVFilterContext * ctx, AVFrame * in, ScanItem * scan, int w, int nb_line )

static

Definition at line 359 of file vf_readeia608.c.

Referenced by extract_lines().

extract_lines()

static int extract_lines ( AVFilterContext * ctx, void * arg, int job, int nb_jobs )

static

Definition at line 443 of file vf_readeia608.c.

Referenced by filter_frame().

filter_frame()

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

static

Definition at line 462 of file vf_readeia608.c.

uninit()

static av_cold void uninit ( AVFilterContext * ctx )

static

Definition at line 497 of file vf_readeia608.c.

process_command()

static int process_command ( AVFilterContext * ctx, const char * cmd, const char * args, char * res, int res_len, int flags )

static

Definition at line 513 of file vf_readeia608.c.

Variable Documentation

readeia608_options

const AVOption readeia608_options[]

static

Initial value:

= {
    { "scan_min", "set from which line to scan for codes",               OFFSET(start), AV_OPT_TYPE_INT,   {.i64=0},     0, INT_MAX, FLAGS },
    { "scan_max", "set to which line to scan for codes",                 OFFSET(end),   AV_OPT_TYPE_INT,   {.i64=29},    0, INT_MAX, FLAGS },
    { "spw",      "set ratio of width reserved for sync code detection", OFFSET(spw),   AV_OPT_TYPE_FLOAT, {.dbl=.27}, 0.1,     0.7, FLAGS },
    { "chp",      "check and apply parity bit",                          OFFSET(chp),   AV_OPT_TYPE_BOOL,  {.i64= 0},    0,       1, FLAGS },
    { "lp",       "lowpass line prior to processing",                    OFFSET(lp),    AV_OPT_TYPE_BOOL,  {.i64= 1},    0,       1, FLAGS },
    { NULL }
}

Definition at line 91 of file vf_readeia608.c.

pixel_fmts

enum AVPixelFormat pixel_fmts[]

static

Initial value:

= {
    AV_PIX_FMT_GRAY8, AV_PIX_FMT_GRAY9,
    AV_PIX_FMT_GRAY10, AV_PIX_FMT_GRAY12, AV_PIX_FMT_GRAY14,
    AV_PIX_FMT_GRAY16,
    AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV411P,
    AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV422P,
    AV_PIX_FMT_YUV440P, AV_PIX_FMT_YUV444P,
    AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P,
    AV_PIX_FMT_YUVJ440P, AV_PIX_FMT_YUVJ444P,
    AV_PIX_FMT_YUVJ411P,
    AV_PIX_FMT_YUV420P9, AV_PIX_FMT_YUV422P9, AV_PIX_FMT_YUV444P9,
    AV_PIX_FMT_YUV420P10, AV_PIX_FMT_YUV422P10, AV_PIX_FMT_YUV444P10,
    AV_PIX_FMT_YUV440P10,
    AV_PIX_FMT_YUV444P12, AV_PIX_FMT_YUV422P12, AV_PIX_FMT_YUV420P12,
    AV_PIX_FMT_YUV440P12,
    AV_PIX_FMT_YUV444P14, AV_PIX_FMT_YUV422P14, AV_PIX_FMT_YUV420P14,
    AV_PIX_FMT_YUV420P16, AV_PIX_FMT_YUV422P16, AV_PIX_FMT_YUV444P16,
    AV_PIX_FMT_YUVA420P,  AV_PIX_FMT_YUVA422P,   AV_PIX_FMT_YUVA444P,
    AV_PIX_FMT_YUVA444P9, AV_PIX_FMT_YUVA444P10, AV_PIX_FMT_YUVA444P12, AV_PIX_FMT_YUVA444P16,
    AV_PIX_FMT_YUVA422P9, AV_PIX_FMT_YUVA422P10, AV_PIX_FMT_YUVA422P12, AV_PIX_FMT_YUVA422P16,
    AV_PIX_FMT_YUVA420P9, AV_PIX_FMT_YUVA420P10, AV_PIX_FMT_YUVA420P16,
    AV_PIX_FMT_NONE
}

Definition at line 102 of file vf_readeia608.c.

readeia608_inputs

const AVFilterPad readeia608_inputs[]

static

Initial value:

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

Definition at line 532 of file vf_readeia608.c.

ff_vf_readeia608

const FFFilter ff_vf_readeia608

Initial value:

= {
    .p.name        = "readeia608",
    .p.description = NULL_IF_CONFIG_SMALL("Read EIA-608 Closed Caption codes from input video and write them to frame metadata."),
    .p.priv_class  = &readeia608_class,
    .p.flags       = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC |
                     AVFILTER_FLAG_SLICE_THREADS            |
                     AVFILTER_FLAG_METADATA_ONLY,
    .priv_size     = sizeof(ReadEIA608Context),
    FILTER_INPUTS(readeia608_inputs),
    FILTER_OUTPUTS(ff_video_default_filterpad),
    FILTER_PIXFMTS_ARRAY(pixel_fmts),
    .uninit        = uninit,
    .process_command = process_command,
}

Definition at line 541 of file vf_readeia608.c.