[FFmpeg-devel] [PATCH] avfilter: add EIA-608 line extractor
Paul B Mahol
onemda at gmail.com
Tue Jan 17 21:43:38 EET 2017
Signed-off-by: Dave Rice <dave at dericed.com>
Signed-off-by: Paul B Mahol <onemda at gmail.com>
---
doc/filters.texi | 70 ++++++++++++
libavfilter/Makefile | 1 +
libavfilter/allfilters.c | 1 +
libavfilter/vf_readeia608.c | 268 ++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 340 insertions(+)
create mode 100644 libavfilter/vf_readeia608.c
diff --git a/doc/filters.texi b/doc/filters.texi
index 94548b1..57170e3 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -11249,6 +11249,76 @@ less than @code{0}, the filter will try to use a good random seed on a
best effort basis.
@end table
+ at section readeia608
+
+Read closed captioning (EIA-608) information from the top lines of a video frame.
+
+This filter adds frame metadata for @code{lavfi.readeia608.cc.X} and
+ at code{lavfi.readeia608.line.X}, where @code{X} is the number of the identified line
+with EIA-608 data (starting from 0). A description of each metadata value follows:
+
+ at table @option
+ at item lavfi.readeia608.cc.X
+The two bytes stored as EIA-608 data (printed in hexadecimal).
+
+ at item lavfi.readeia608.line.X
+The number of the line on which the EIA-608 data was identified and read.
+ at end table
+
+This filter accepts the following options:
+
+ at table @option
+ at item start
+Set the line to start scanning for EIA-608 data. Default is @code{0}.
+
+ at item end
+Set the line to end scanning for EIA-608 data. Default is @code{29}.
+
+ at item mac
+Set minimal acceptable amplitude change for sync codes detection.
+Default is @code{0.2}. Allowed range is @code{[0.001 - 1]}.
+
+ at item spw
+Set the ratio of width reserved for sync code detection.
+Default is @code{0.27}. Allowed range is @code{[0.01 - 0.7]}.
+
+ at item mhd
+Set the max peaks height difference for sync code detection.
+Default is @code{0.1}. Allowed range is @code{[0.0 - 0.5]}.
+
+ at item mpd
+Set max peaks period difference for sync code detection.
+Default is @code{0.1}. Allowed range is @code{[0.0 - 0.5]}.
+
+ at item msd
+Set the first two max start code bits differences.
+Default is @code{0.02}. Allowed range is @code{[0.0 - 0.5]}.
+
+ at item bhd
+Set the minimum ratio of bits height compared to 3rd start code bit.
+Default is @code{0.75}. Allowed range is @code{[0.01 - 1]}.
+
+ at item wth
+Set the white color threshold. Default is @code{0.35}. Allowed range is @code{[0.1 - 1]}.
+
+ at item bth
+Set the black color threshold. Default is @code{0.15}. Allowed range is @code{[0.0 - 0.5]}.
+
+ at item chp
+Enable checking the parity bit. In the event of a parity error, the filter will output
+ at code{0x00} for that character. Default is false.
+ at end table
+
+ at subsection Examples
+
+ at itemize
+ at item
+Output a csv with presentation time and the first two lines of identified EIA-608 captioning data.
+ at example
+ffprobe -f lavfi -i movie=captioned_video.mov,readeia608 -show_entries frame=pkt_pts_time:frame_tags=lavfi.readeia608.cc.0,lavfi.readeia608.cc.1 -of csv
+ at end example
+ at end itemize
+
@section readvitc
Read vertical interval timecode (VITC) information from the top lines of a
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index 9ab65eb..5afb72a 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -247,6 +247,7 @@ OBJS-$(CONFIG_PSNR_FILTER) += vf_psnr.o dualinput.o framesync.
OBJS-$(CONFIG_PULLUP_FILTER) += vf_pullup.o
OBJS-$(CONFIG_QP_FILTER) += vf_qp.o
OBJS-$(CONFIG_RANDOM_FILTER) += vf_random.o
+OBJS-$(CONFIG_READEIA608_FILTER) += vf_readeia608.o
OBJS-$(CONFIG_READVITC_FILTER) += vf_readvitc.o
OBJS-$(CONFIG_REALTIME_FILTER) += f_realtime.o
OBJS-$(CONFIG_REMAP_FILTER) += vf_remap.o framesync.o
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 2c37818..4664245 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -262,6 +262,7 @@ void avfilter_register_all(void)
REGISTER_FILTER(PULLUP, pullup, vf);
REGISTER_FILTER(QP, qp, vf);
REGISTER_FILTER(RANDOM, random, vf);
+ REGISTER_FILTER(READEIA608, readeia608, vf);
REGISTER_FILTER(READVITC, readvitc, vf);
REGISTER_FILTER(REALTIME, realtime, vf);
REGISTER_FILTER(REMAP, remap, vf);
diff --git a/libavfilter/vf_readeia608.c b/libavfilter/vf_readeia608.c
new file mode 100644
index 0000000..4fa1446
--- /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[] = {
+ { "start", "set from which line to scan for codes", OFFSET(start), AV_OPT_TYPE_INT, {.i64=0}, 0, INT_MAX, FLAGS },
+ { "end", "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 },
+ { "wth", "set white color threshold", OFFSET(wth), AV_OPT_TYPE_FLOAT, {.dbl=.35}, 0.1, 1, FLAGS },
+ { "bth", "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.cc.%d", 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.line.%d", 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 it 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,
+};
--
2.9.3
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