| /* |
| * 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, |
| }; |