[FFmpeg-devel] avfilter: add EIA-608 line extractor

Message ID	20170117194338.11992-1-onemda@gmail.com
State	Accepted
Headers	show Delivered-To: ffmpegpatchwork@gmail.com Received-SPF: pass (google.com: domain of ffmpeg-devel-bounces@ffmpeg.org designates 79.124.17.100 as permitted sender) client-ip=79.124.17.100; From: Paul B Mahol <onemda@gmail.com> To: ffmpeg-devel@ffmpeg.org Date: Tue, 17 Jan 2017 20:43:38 +0100 Message-Id: <20170117194338.11992-1-onemda@gmail.com> Subject: [FFmpeg-devel] [PATCH] avfilter: add EIA-608 line extractor Precedence: list Reply-To: FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" <ffmpeg-devel-bounces@ffmpeg.org>

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 +@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 +@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: + +@table @option +@item lavfi.readeia608.cc.X +The two bytes stored as EIA-608 data (printed in hexadecimal). + +@item lavfi.readeia608.line.X +The number of the line on which the EIA-608 data was identified and read. +@end table + +This filter accepts the following options: + +@table @option +@item start +Set the line to start scanning for EIA-608 data. Default is @code{0}. + +@item end +Set the line to end scanning for EIA-608 data. Default is @code{29}. + +@item mac +Set minimal acceptable amplitude change for sync codes detection. +Default is @code{0.2}. Allowed range is @code{[0.001 - 1]}. + +@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]}. + +@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]}. + +@item mpd +Set max peaks period difference for sync code detection. +Default is @code{0.1}. Allowed range is @code{[0.0 - 0.5]}. + +@item msd +Set the first two max start code bits differences. +Default is @code{0.02}. Allowed range is @code{[0.0 - 0.5]}. + +@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]}. + +@item wth +Set the white color threshold. Default is @code{0.35}. Allowed range is @code{[0.1 - 1]}. + +@item bth +Set the black color threshold. Default is @code{0.15}. Allowed range is @code{[0.0 - 0.5]}. + +@item chp +Enable checking the parity bit. In the event of a parity error, the filter will output +@code{0x00} for that character. Default is false. +@end table + +@subsection Examples + +@itemize +@item +Output a csv with presentation time and the first two lines of identified EIA-608 captioning data. +@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 +@end example +@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, +};

[FFmpeg-devel] avfilter: add EIA-608 line extractor

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