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authorPaul B Mahol <onemda@gmail.com>2017-01-14 19:04:54 +0100
committerPaul B Mahol <onemda@gmail.com>2017-01-24 10:20:10 +0100
commit08e5732318a46fd1fe9a406ff829838483dc1358 (patch)
tree3e80cdb6ee646ce924e9ee3a71cdc82328cbd5b5 /libavfilter/vf_readeia608.c
parent1bb192ef6c1771ee18d1c5ed31d7c0cac8a25ebb (diff)
downloadffmpeg-08e5732318a46fd1fe9a406ff829838483dc1358.tar.gz
avfilter: add EIA-608 line extractor
Signed-off-by: Dave Rice <dave@dericed.com> Signed-off-by: Paul B Mahol <onemda@gmail.com>
Diffstat (limited to 'libavfilter/vf_readeia608.c')
-rw-r--r--libavfilter/vf_readeia608.c268
1 files changed, 268 insertions, 0 deletions
diff --git a/libavfilter/vf_readeia608.c b/libavfilter/vf_readeia608.c
new file mode 100644
index 0000000000..4bfe9cfe75
--- /dev/null
+++ b/libavfilter/vf_readeia608.c
@@ -0,0 +1,268 @@
+/*
+ * 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(avpriv_frame_get_metadatap(in), key, value, 0);
+
+ snprintf(key, sizeof(key), "lavfi.readeia608.%d.line", s->nb_found);
+ snprintf(value, sizeof(value), "%d", line);
+ av_dict_set(avpriv_frame_get_metadatap(in), 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,
+};