/* * 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 FALL 0 #define RISE 1 typedef struct ReadEIA608Context { const AVClass *class; int start, end; int min_range; int max_peak_diff; int max_period_diff; int max_start_diff; int nb_found; int white; int black; float mpd, mhd, msd, mac, spw, bhd, wth, bth; int chp; } ReadEIA608Context; #define OFFSET(x) offsetof(ReadEIA608Context, x) #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_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 }, { "mac", "set minimal acceptable amplitude change for sync codes detection", OFFSET(mac), AV_OPT_TYPE_FLOAT, {.dbl=.2}, 0.001, 1, FLAGS }, { "spw", "set ratio of width reserved for sync code detection", OFFSET(spw), AV_OPT_TYPE_FLOAT, {.dbl=.27}, 0.1, 0.7, FLAGS }, { "mhd", "set max peaks height difference for sync code detection", OFFSET(mhd), AV_OPT_TYPE_FLOAT, {.dbl=.1}, 0, 0.5, FLAGS }, { "mpd", "set max peaks period difference for sync code detection", OFFSET(mpd), AV_OPT_TYPE_FLOAT, {.dbl=.1}, 0, 0.5, FLAGS }, { "msd", "set first two max start code bits differences", OFFSET(msd), AV_OPT_TYPE_FLOAT, {.dbl=.02}, 0, 0.5, FLAGS }, { "bhd", "set min ratio of bits height compared to 3rd start code bit", OFFSET(bhd), AV_OPT_TYPE_FLOAT, {.dbl=.75}, 0.01, 1, FLAGS }, { "th_w", "set white color threshold", OFFSET(wth), AV_OPT_TYPE_FLOAT, {.dbl=.35}, 0.1, 1, FLAGS }, { "th_b", "set black color threshold", OFFSET(bth), AV_OPT_TYPE_FLOAT, {.dbl=.15}, 0, 0.5, FLAGS }, { "chp", "check and apply parity bit", OFFSET(chp), AV_OPT_TYPE_BOOL, {.i64= 0}, 0, 1, FLAGS }, { NULL } }; AVFILTER_DEFINE_CLASS(readeia608); static int query_formats(AVFilterContext *ctx) { static const enum AVPixelFormat pixel_fmts[] = { AV_PIX_FMT_GRAY8, 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_NONE }; AVFilterFormats *formats = ff_make_format_list(pixel_fmts); if (!formats) return AVERROR(ENOMEM); return ff_set_common_formats(ctx, formats); } static int config_input(AVFilterLink *inlink) { const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format); AVFilterContext *ctx = inlink->dst; ReadEIA608Context *s = ctx->priv; int depth = desc->comp[0].depth; if (s->end >= inlink->h) { av_log(ctx, AV_LOG_WARNING, "Last line to scan too large, clipping.\n"); s->end = inlink->h - 1; } if (s->start > s->end) { av_log(ctx, AV_LOG_ERROR, "Invalid range.\n"); return AVERROR(EINVAL); } s->min_range = s->mac * ((1 << depth) - 1); s->max_peak_diff = s->mhd * ((1 << depth) - 1); s->max_period_diff = s->mpd * ((1 << depth) - 1); s->max_start_diff = s->msd * ((1 << depth) - 1); s->white = s->wth * ((1 << depth) - 1); s->black = s->bth * ((1 << depth) - 1); return 0; } static void extract_line(AVFilterContext *ctx, AVFilterLink *inlink, AVFrame *in, int line) { ReadEIA608Context *s = ctx->priv; int max = 0, min = INT_MAX; int i, ch, range = 0; const uint8_t *src; uint16_t clock[8][2] = { { 0 } }; const int sync_width = s->spw * in->width; int last = 0, peaks = 0, max_peak_diff = 0, dir = RISE; const int width_per_bit = (in->width - sync_width) / 19; uint8_t byte[2] = { 0 }; int s1, s2, s3, parity; src = &in->data[0][line * in->linesize[0]]; for (i = 0; i < sync_width; i++) { max = FFMAX(max, src[i]); min = FFMIN(min, src[i]); } range = max - min; if (range < s->min_range) return; for (i = 0; i < sync_width; i++) { int Y = src[i]; if (dir == RISE) { if (Y < last) { dir = FALL; if (last >= s->white) { clock[peaks][0] = last; clock[peaks][1] = i; peaks++; if (peaks > 7) break; } } } else if (dir == FALL) { if (Y > last && last <= s->black) { dir = RISE; } } last = Y; } if (peaks != 7) return; for (i = 1; i < 7; i++) max_peak_diff = FFMAX(max_peak_diff, FFABS(clock[i][0] - clock[i-1][0])); if (max_peak_diff > s->max_peak_diff) return; max = 0; min = INT_MAX; for (i = 1; i < 7; i++) { max = FFMAX(max, FFABS(clock[i][1] - clock[i-1][1])); min = FFMIN(min, FFABS(clock[i][1] - clock[i-1][1])); } range = max - min; if (range > s->max_period_diff) return; s1 = src[sync_width + width_per_bit * 0 + width_per_bit / 2]; s2 = src[sync_width + width_per_bit * 1 + width_per_bit / 2]; s3 = src[sync_width + width_per_bit * 2 + width_per_bit / 2]; if (FFABS(s1 - s2) > s->max_start_diff || s1 > s->black || s2 > s->black || s3 < s->white) return; for (ch = 0; ch < 2; ch++) { for (parity = 0, i = 0; i < 8; i++) { int b = src[sync_width + width_per_bit * (i + 3 + 8 * ch) + width_per_bit / 2]; if (b - s1 > (s3 - s1) * s->bhd) { b = 1; parity++; } else { b = 0; } byte[ch] |= b << i; } if (s->chp) { if (!(parity & 1)) { byte[ch] = 0; } } } { uint8_t key[128], value[128]; snprintf(key, sizeof(key), "lavfi.readeia608.%d.cc", s->nb_found); snprintf(value, sizeof(value), "0x%02X%02X", byte[0], byte[1]); av_dict_set(&in->metadata, key, value, 0); snprintf(key, sizeof(key), "lavfi.readeia608.%d.line", s->nb_found); snprintf(value, sizeof(value), "%d", line); av_dict_set(&in->metadata, key, value, 0); } s->nb_found++; } static int filter_frame(AVFilterLink *inlink, AVFrame *in) { AVFilterContext *ctx = inlink->dst; AVFilterLink *outlink = ctx->outputs[0]; ReadEIA608Context *s = ctx->priv; int i; s->nb_found = 0; for (i = s->start; i <= s->end; i++) extract_line(ctx, inlink, in, i); return ff_filter_frame(outlink, in); } static const AVFilterPad readeia608_inputs[] = { { .name = "default", .type = AVMEDIA_TYPE_VIDEO, .filter_frame = filter_frame, .config_props = config_input, }, { NULL } }; static const AVFilterPad readeia608_outputs[] = { { .name = "default", .type = AVMEDIA_TYPE_VIDEO, }, { NULL } }; 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, .query_formats = query_formats, .inputs = readeia608_inputs, .outputs = readeia608_outputs, .flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC, };