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FFmpeg/libavfilter/vf_readeia608.c

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/*
* Copyright (c) 2017 Paul B Mahol
*
* 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
*/
/**
* @file
* Filter for reading closed captioning data (EIA-608).
* See also https://en.wikipedia.org/wiki/EIA-608
*/
#include <string.h>
#include "libavutil/internal.h"
#include "libavutil/opt.h"
#include "libavutil/pixdesc.h"
#include "libavutil/timestamp.h"
#include "avfilter.h"
#include "formats.h"
#include "internal.h"
#include "video.h"
#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
typedef struct LineItem {
int input;
int output;
float unfiltered;
float filtered;
float average;
float deviation;
} LineItem;
typedef struct CodeItem {
uint8_t bit;
int size;
} CodeItem;
typedef struct ScanItem {
int nb_line;
int found;
int white;
int black;
uint64_t *histogram;
uint8_t byte[2];
CodeItem *code;
LineItem *line;
} ScanItem;
typedef struct ReadEIA608Context {
const AVClass *class;
int start, end;
float spw;
int chp;
int lp;
int depth;
int max;
int nb_allocated;
ScanItem *scan;
void (*read_line[2])(AVFrame *in, int nb_line,
LineItem *line, int lp, int w);
} ReadEIA608Context;
#define OFFSET(x) offsetof(ReadEIA608Context, x)
#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_RUNTIME_PARAM
static const AVOption readeia608_options[] = {
{ "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 }
};
AVFILTER_DEFINE_CLASS(readeia608);
static const enum AVPixelFormat pixel_fmts[] = {
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
};
static int config_filter(AVFilterContext *ctx, int start, int end)
{
ReadEIA608Context *s = ctx->priv;
AVFilterLink *inlink = ctx->inputs[0];
int size = inlink->w + LAG;
if (end >= inlink->h) {
av_log(ctx, AV_LOG_WARNING, "Last line to scan too large, clipping.\n");
end = inlink->h - 1;
}
if (start > end) {
av_log(ctx, AV_LOG_ERROR, "Invalid range.\n");
return AVERROR(EINVAL);
}
if (s->nb_allocated < end - start + 1) {
const int diff = end - start + 1 - s->nb_allocated;
s->scan = av_realloc_f(s->scan, end - start + 1, sizeof(*s->scan));
if (!s->scan)
return AVERROR(ENOMEM);
memset(&s->scan[s->nb_allocated], 0, diff * sizeof(*s->scan));
s->nb_allocated = end - start + 1;
}
for (int i = 0; i < s->nb_allocated; i++) {
ScanItem *scan = &s->scan[i];
if (!scan->histogram)
scan->histogram = av_calloc(s->max + 1, sizeof(*scan->histogram));
if (!scan->line)
scan->line = av_calloc(size, sizeof(*scan->line));
if (!scan->code)
scan->code = av_calloc(size, sizeof(*scan->code));
if (!scan->line || !scan->code || !scan->histogram)
return AVERROR(ENOMEM);
}
s->start = start;
s->end = end;
return 0;
}
static void build_histogram(ReadEIA608Context *s, ScanItem *scan, const LineItem *line, int len)
{
memset(scan->histogram, 0, (s->max + 1) * sizeof(*scan->histogram));
for (int i = LAG; i < len + LAG; i++)
scan->histogram[line[i].input]++;
}
static void find_black_and_white(ReadEIA608Context *s, ScanItem *scan)
{
const int max = s->max;
int start = 0, end = 0, middle;
int black = 0, white = 0;
int cnt;
for (int i = 0; i <= max; i++) {
if (scan->histogram[i]) {
start = i;
break;
}
}
for (int i = max; i >= 0; i--) {
if (scan->histogram[i]) {
end = i;
break;
}
}
middle = start + (end - start) / 2;
cnt = 0;
for (int i = start; i <= middle; i++) {
if (scan->histogram[i] > cnt) {
cnt = scan->histogram[i];
black = i;
}
}
cnt = 0;
for (int i = end; i >= middle; i--) {
if (scan->histogram[i] > cnt) {
cnt = scan->histogram[i];
white = i;
}
}
scan->black = black;
scan->white = white;
}
static float meanf(const LineItem *line, int len)
{
float sum = 0.0, mean = 0.0;
for (int i = 0; i < len; i++)
sum += line[i].filtered;
mean = sum / len;
return mean;
}
static float stddevf(const LineItem *line, int len)
{
float m = meanf(line, len);
float standard_deviation = 0.f;
for (int i = 0; i < len; i++)
standard_deviation += (line[i].filtered - m) * (line[i].filtered - m);
return sqrtf(standard_deviation / (len - 1));
}
static void thresholding(ReadEIA608Context *s, ScanItem *scan, LineItem *line,
int lag, float threshold, float influence, int len)
{
for (int i = lag; i < len + lag; i++) {
line[i].unfiltered = line[i].input / 255.f;
line[i].filtered = line[i].unfiltered;
}
for (int i = 0; i < lag; i++) {
line[i].unfiltered = meanf(line, len * s->spw);
line[i].filtered = line[i].unfiltered;
}
line[lag - 1].average = meanf(line, lag);
line[lag - 1].deviation = stddevf(line, lag);
for (int i = lag; i < len + lag; i++) {
if (fabsf(line[i].unfiltered - line[i-1].average) > threshold * line[i-1].deviation) {
if (line[i].unfiltered > line[i-1].average) {
line[i].output = 255;
} else {
line[i].output = 0;
}
line[i].filtered = influence * line[i].unfiltered + (1.f - influence) * line[i-1].filtered;
} else {
int distance_from_black, distance_from_white;
distance_from_black = FFABS(line[i].input - scan->black);
distance_from_white = FFABS(line[i].input - scan->white);
line[i].output = distance_from_black <= distance_from_white ? 0 : 255;
}
line[i].average = meanf(line + i - lag, lag);
line[i].deviation = stddevf(line + i - lag, lag);
}
}
static int periods(const LineItem *line, CodeItem *code, int len)
{
int hold = line[LAG].output, cnt = 0;
int last = LAG;
memset(code, 0, len * sizeof(*code));
for (int i = LAG + 1; i < len + LAG; i++) {
if (line[i].output != hold) {
code[cnt].size = i - last;
code[cnt].bit = hold;
hold = line[i].output;
last = i;
cnt++;
}
}
code[cnt].size = LAG + len - last;
code[cnt].bit = hold;
return cnt + 1;
}
static void dump_code(AVFilterContext *ctx, ScanItem *scan, int len, int item)
{
av_log(ctx, AV_LOG_DEBUG, "%d:", item);
for (int i = 0; i < len; i++) {
av_log(ctx, AV_LOG_DEBUG, " %03d", scan->code[i].size);
}
av_log(ctx, AV_LOG_DEBUG, "\n");
}
#define READ_LINE(type, name) \
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]; \
} \
} \
}
READ_LINE(uint8_t, byte)
READ_LINE(uint16_t, word)
static int config_input(AVFilterLink *inlink)
{
AVFilterContext *ctx = inlink->dst;
ReadEIA608Context *s = ctx->priv;
const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
if (!desc)
return AVERROR_BUG;
s->depth = desc->comp[0].depth;
s->max = (1 << desc->comp[0].depth) - 1;
s->read_line[0] = read_byte;
s->read_line[1] = read_word;
return config_filter(ctx, s->start, s->end);
}
static void extract_line(AVFilterContext *ctx, AVFrame *in, ScanItem *scan, int w, int nb_line)
{
ReadEIA608Context *s = ctx->priv;
LineItem *line = scan->line;
int i, j, ch, len;
uint8_t codes[19] = { 0 };
float bit_size = 0.f;
int parity;
memset(line, 0, (w + LAG) * sizeof(*line));
scan->byte[0] = scan->byte[1] = 0;
scan->found = 0;
s->read_line[s->depth > 8](in, nb_line, line, s->lp, w);
build_histogram(s, scan, line, w);
find_black_and_white(s, scan);
if (scan->white - scan->black < 5)
return;
thresholding(s, scan, line, LAG, 1, 0, w);
len = periods(line, scan->code, w);
dump_code(ctx, scan, len, nb_line);
if (len < 15 ||
scan->code[14].bit != 0 ||
w / (float)scan->code[14].size < SYNC_BITSIZE_MIN ||
w / (float)scan->code[14].size > SYNC_BITSIZE_MAX) {
return;
}
for (i = 14; i < len; i++) {
bit_size += scan->code[i].size;
}
bit_size /= 19.f;
for (i = 1; i < 14; i++) {
if (scan->code[i].size / bit_size > CLOCK_BITSIZE_MAX ||
scan->code[i].size / bit_size < CLOCK_BITSIZE_MIN) {
return;
}
}
if (scan->code[15].size / bit_size < 0.45f) {
return;
}
for (j = 0, i = 14; i < len; i++) {
int run, bit;
run = lrintf(scan->code[i].size / bit_size);
bit = scan->code[i].bit;
for (int k = 0; j < 19 && k < run; k++) {
codes[j++] = bit;
}
if (j >= 19)
break;
}
for (ch = 0; ch < 2; ch++) {
for (parity = 0, i = 0; i < 8; i++) {
int b = codes[3 + ch * 8 + i];
if (b == 255) {
parity++;
b = 1;
} else {
b = 0;
}
scan->byte[ch] |= b << i;
}
if (s->chp) {
if (!(parity & 1)) {
scan->byte[ch] = 0x7F;
}
}
}
scan->nb_line = nb_line;
scan->found = 1;
}
static int extract_lines(AVFilterContext *ctx, void *arg,
int job, int nb_jobs)
{
ReadEIA608Context *s = ctx->priv;
AVFilterLink *inlink = ctx->inputs[0];
const int h = s->end - s->start + 1;
const int start = (h * job) / nb_jobs;
const int end = (h * (job+1)) / nb_jobs;
AVFrame *in = arg;
for (int i = start; i < end; i++) {
ScanItem *scan = &s->scan[i];
extract_line(ctx, in, scan, inlink->w, s->start + i);
}
return 0;
}
static int filter_frame(AVFilterLink *inlink, AVFrame *in)
{
AVFilterContext *ctx = inlink->dst;
AVFilterLink *outlink = ctx->outputs[0];
ReadEIA608Context *s = ctx->priv;
int nb_found;
ff_filter_execute(ctx, extract_lines, in, NULL,
FFMIN(FFMAX(s->end - s->start + 1, 1), ff_filter_get_nb_threads(ctx)));
nb_found = 0;
for (int i = 0; i < s->end - s->start + 1; i++) {
ScanItem *scan = &s->scan[i];
uint8_t key[128], value[128];
if (!scan->found)
continue;
//snprintf(key, sizeof(key), "lavfi.readeia608.%d.bits", nb_found);
//snprintf(value, sizeof(value), "0b%d%d%d%d%d%d%d%d 0b%d%d%d%d%d%d%d%d", codes[3]==255,codes[4]==255,codes[5]==255,codes[6]==255,codes[7]==255,codes[8]==255,codes[9]==255,codes[10]==255,codes[11]==255,codes[12]==255,codes[13]==255,codes[14]==255,codes[15]==255,codes[16]==255,codes[17]==255,codes[18]==255);
//av_dict_set(&in->metadata, key, value, 0);
snprintf(key, sizeof(key), "lavfi.readeia608.%d.cc", nb_found);
snprintf(value, sizeof(value), "0x%02X%02X", scan->byte[0], scan->byte[1]);
av_dict_set(&in->metadata, key, value, 0);
snprintf(key, sizeof(key), "lavfi.readeia608.%d.line", nb_found);
av_dict_set_int(&in->metadata, key, scan->nb_line, 0);
nb_found++;
}
return ff_filter_frame(outlink, in);
}
static av_cold void uninit(AVFilterContext *ctx)
{
ReadEIA608Context *s = ctx->priv;
for (int i = 0; i < s->nb_allocated; i++) {
ScanItem *scan = &s->scan[i];
av_freep(&scan->histogram);
av_freep(&scan->code);
av_freep(&scan->line);
}
s->nb_allocated = 0;
av_freep(&s->scan);
}
static int process_command(AVFilterContext *ctx, const char *cmd, const char *args,
char *res, int res_len, int flags)
{
ReadEIA608Context *s = ctx->priv;
int ret, start = s->start, end = s->end;
ret = ff_filter_process_command(ctx, cmd, args, res, res_len, flags);
if (ret < 0)
return ret;
ret = config_filter(ctx, s->start, s->end);
if (ret < 0) {
s->start = start;
s->end = end;
}
return 0;
}
static const AVFilterPad readeia608_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.filter_frame = filter_frame,
.config_props = config_input,
},
};
static const AVFilterPad readeia608_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
},
};
const AVFilter ff_vf_readeia608 = {
.name = "readeia608",
.description = NULL_IF_CONFIG_SMALL("Read EIA-608 Closed Caption codes from input video and write them to frame metadata."),
.priv_size = sizeof(ReadEIA608Context),
.priv_class = &readeia608_class,
FILTER_INPUTS(readeia608_inputs),
FILTER_OUTPUTS(readeia608_outputs),
FILTER_PIXFMTS_ARRAY(pixel_fmts),
.uninit = uninit,
.flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC |
AVFILTER_FLAG_SLICE_THREADS |
AVFILTER_FLAG_METADATA_ONLY,
.process_command = process_command,
};
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