[FFmpeg-devel] [PATCH v6 09/11] avfilter/textmod: Add textmod filter
Soft Works
softworkz at hotmail.com
Thu Sep 16 23:30:31 EEST 2021
- textmod {S -> S)
Modify subtitle text in a number of ways
Signed-off-by: softworkz <softworkz at hotmail.com>
---
doc/filters.texi | 64 +++++++
libavfilter/Makefile | 3 +
libavfilter/allfilters.c | 1 +
libavfilter/sf_textmod.c | 372 +++++++++++++++++++++++++++++++++++++++
4 files changed, 440 insertions(+)
create mode 100644 libavfilter/sf_textmod.c
diff --git a/doc/filters.texi b/doc/filters.texi
index 1c38ecd8ec..1832dc8847 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -25087,6 +25087,70 @@ existing filters using @code{--disable-filters}.
Below is a description of the currently available subtitle filters.
+ at section textmod
+
+Modify subtitle text in a number of ways.
+
+It accepts the following parameters:
+
+ at table @option
+ at item mode
+The kind of text modification to apply
+
+Supported operation modes are:
+
+ at table @var
+ at item 0, leet
+Convert subtitle text to 'leet speak'. It's primarily useful for testing as the modification will be visible with almost all text lines.
+ at item 1, to_upper
+Change all text to upper case. Might improve readability.
+ at item 2, to_lower
+Change all text to lower case.
+ at item 3, replace_chars
+Replace one or more characters. Requires the find and replace parameters to be specified.
+Both need to be equal in length.
+The first char in find is replaced by the first char in replace, same for all subsequent chars.
+ at item 4, remove_chars
+Remove certain characters. Requires the find parameter to be specified.
+All chars in the find parameter string will be removed from all subtitle text.
+ at item 5, replace_words
+Replace one or more words. Requires the find and replace parameters to be specified. Multiple words must be separated by the delimiter char specified vie the separator parameter (default: ',').
+The number of words in the find and replace parameters needs to be equal.
+The first word in find is replaced by the first word in replace, same for all subsequent words
+ at item 6, remove_words
+Remove certain words. Requires the find parameter to be specified. Multiple words must be separated by the delimiter char specified vie the separator parameter (default: ',').
+All words in the find parameter string will be removed from all subtitle text.
+ at end table
+
+ at item find
+Required for replace_chars, remove_chars, replace_words and remove_words.
+
+ at item replace
+Required for replace_chars and replace_words.
+
+ at item separator
+Delimiter character for words. Used with replace_words and remove_words- Must be a single character.
+The default is '.'.
+
+ at end table
+
+ at subsection Examples
+
+ at itemize
+ at item
+Change all characters to upper case while keeping all styles and animations:
+ at example
+ffmpeg -i "https://streams.videolan.org/ffmpeg/mkv_subtitles.mkv" -filter_complex "[0:s]textmod=mode=to_upper" -map 0 -y out.mkv
+ at end example
+ at item
+Mark the 100-pixel-wide region on the left edge of the frame as very
+uninteresting (to be encoded at much lower quality than the rest of
+the frame).
+ at example
+addroi=0:0:100:ih:+1/5
+ at end example
+ at end itemize
+
@section graphicsub2video
Renders graphic subtitles as video frames.
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index c0b1cc7001..630f701a5f 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -536,6 +536,9 @@ OBJS-$(CONFIG_YUVTESTSRC_FILTER) += vsrc_testsrc.o
OBJS-$(CONFIG_NULLSINK_FILTER) += vsink_nullsink.o
+# subtitle filters
+OBJS-$(CONFIG_TEXTMOD_FILTER) += sf_textmod.o
+
# multimedia filters
OBJS-$(CONFIG_ABITSCOPE_FILTER) += avf_abitscope.o
OBJS-$(CONFIG_ADRAWGRAPH_FILTER) += f_drawgraph.o
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 8543fa22e9..63e41b637d 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -526,6 +526,7 @@ extern const AVFilter ff_avf_showvolume;
extern const AVFilter ff_avf_showwaves;
extern const AVFilter ff_avf_showwavespic;
extern const AVFilter ff_vaf_spectrumsynth;
+extern const AVFilter ff_sf_textmod;
extern const AVFilter ff_svf_graphicsub2video;
extern const AVFilter ff_svf_textsub2video;
diff --git a/libavfilter/sf_textmod.c b/libavfilter/sf_textmod.c
new file mode 100644
index 0000000000..6a29a2d3c0
--- /dev/null
+++ b/libavfilter/sf_textmod.c
@@ -0,0 +1,372 @@
+/*
+ * Copyright (c) 2021 softworkz
+ *
+ * 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
+ * text subtitle filter which allows to modify subtitle text in several ways
+ */
+
+#include <libavcodec/ass.h>
+
+#include "libavutil/avassert.h"
+#include "libavutil/avstring.h"
+#include "libavutil/opt.h"
+#include "avfilter.h"
+#include "internal.h"
+#include "libavcodec/avcodec.h"
+#include "libavcodec/ass_split.h"
+
+static const char* leet_src = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
+static const char* leet_dst = "abcd3f6#1jklmn0pq257uvwxyzAB(D3F6#1JKLMN0PQ257UVWXYZ";
+
+enum TextModOperation {
+ OP_LEET,
+ OP_TO_UPPER,
+ OP_TO_LOWER,
+ OP_REPLACE_CHARS,
+ OP_REMOVE_CHARS,
+ OP_REPLACE_WORDS,
+ OP_REMOVE_WORDS,
+ NB_OPS,
+};
+
+typedef struct TextModContext {
+ const AVClass *class;
+ enum AVSubtitleType format;
+ enum TextModOperation operation;
+ char *find;
+ char *replace;
+ char *separator;
+ char **find_list;
+ int nb_find_list;
+ char **replace_list;
+ int nb_replace_list;
+} TextModContext;
+
+static char **split_string(char *source, int *nb_elems, char delim)
+{
+ char **list = NULL;
+ char *temp = NULL;
+ char *ptr = av_strtok(source, &delim, &temp);
+
+ while (ptr) {
+ av_dynarray_add(&list, nb_elems, ptr);
+ if (!list)
+ return NULL;
+
+ ptr = av_strtok(NULL, &delim, &temp);
+ }
+
+ return list;
+}
+
+static int init(AVFilterContext *ctx)
+{
+ TextModContext *s = ctx->priv;
+
+ switch (s->operation) {
+ case OP_REPLACE_CHARS:
+ case OP_REMOVE_CHARS:
+ case OP_REPLACE_WORDS:
+ case OP_REMOVE_WORDS:
+ if (!s->find || !strlen(s->find)) {
+ av_log(ctx, AV_LOG_ERROR, "Selected mode requires the 'find' parameter to be specified");
+ return AVERROR(EINVAL);
+ }
+ break;
+ }
+
+ switch (s->operation) {
+ case OP_REPLACE_CHARS:
+ case OP_REPLACE_WORDS:
+ if (!s->replace || !strlen(s->replace)) {
+ av_log(ctx, AV_LOG_ERROR, "Selected mode requires the 'replace' parameter to be specified");
+ return AVERROR(EINVAL);
+ }
+ break;
+ }
+
+ if (s->operation == OP_REPLACE_CHARS && strlen(s->find) != strlen(s->replace)) {
+ av_log(ctx, AV_LOG_ERROR, "Selected mode requires the 'find' and 'replace' parameters to have the same length");
+ return AVERROR(EINVAL);
+ }
+
+ if (s->operation == OP_REPLACE_WORDS || s->operation == OP_REMOVE_WORDS) {
+ if (!s->separator || strlen(s->separator) != 1) {
+ av_log(ctx, AV_LOG_ERROR, "Selected mode requires a single separator char to be specified");
+ return AVERROR(EINVAL);
+ }
+
+ s->find_list = split_string(s->find, &s->nb_find_list, *s->separator);
+ if (!s->find_list)
+ return AVERROR(ENOMEM);
+
+ if (s->operation == OP_REPLACE_WORDS) {
+
+ s->replace_list = split_string(s->replace, &s->nb_replace_list, *s->separator);
+ if (!s->replace_list)
+ return AVERROR(ENOMEM);
+
+ if (s->nb_find_list != s->nb_replace_list) {
+ av_log(ctx, AV_LOG_ERROR, "The number of words in 'find' and 'replace' needs to be equal");
+ return AVERROR(EINVAL);
+ }
+ }
+ }
+
+ return 0;
+}
+
+static void uninit(AVFilterContext *ctx)
+{
+ TextModContext *s = ctx->priv;
+ int i;
+
+ s->nb_find_list = 0;
+ av_freep(&s->find_list);
+
+ s->nb_replace_list = 0;
+ av_freep(&s->replace_list);
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+ AVFilterFormats *formats;
+ AVFilterLink *inlink = ctx->inputs[0];
+ AVFilterLink *outlink = ctx->outputs[0];
+ static const enum AVSubtitleType subtitle_fmts[] = { AV_SUBTITLE_FMT_ASS, AV_SUBTITLE_FMT_NONE };
+ int ret;
+
+ /* set input subtitle format */
+ formats = ff_make_format_list(subtitle_fmts);
+ if ((ret = ff_formats_ref(formats, &inlink->outcfg.formats)) < 0)
+ return ret;
+
+ /* set output video format */
+ if ((ret = ff_formats_ref(formats, &outlink->incfg.formats)) < 0)
+ return ret;
+
+ return 0;
+}
+
+static char *process_text(TextModContext *s, char *text)
+{
+ const char *char_src = s->find;
+ const char *char_dst = s->replace;
+ char *result = NULL;
+ int escape_level = 0, k = 0;
+
+ switch (s->operation) {
+ case OP_LEET:
+ case OP_REPLACE_CHARS:
+
+ if (s->operation == OP_LEET) {
+ char_src = leet_src;
+ char_dst = leet_dst;
+ }
+
+ result = av_strdup(text);
+ if (!result)
+ return NULL;
+
+ for (size_t n = 0; n < strlen(result); n++) {
+ if (result[n] == '{')
+ escape_level++;
+
+ if (!escape_level) {
+ for (size_t t = 0; t < FF_ARRAY_ELEMS(char_src); t++) {
+ if (result[n] == char_src[t]) {
+ result[n] = char_dst[t];
+ break;
+ }
+ }
+ }
+
+ if (result[n] == '}')
+ escape_level--;
+ }
+
+ break;
+ case OP_TO_UPPER:
+ case OP_TO_LOWER:
+
+ result = av_strdup(text);
+ if (!result)
+ return NULL;
+
+ for (size_t n = 0; n < strlen(result); n++) {
+ if (result[n] == '{')
+ escape_level++;
+ if (!escape_level)
+ result[n] = s->operation == OP_TO_LOWER ? av_tolower(result[n]) : av_toupper(result[n]);
+ if (result[n] == '}')
+ escape_level--;
+ }
+
+ break;
+ case OP_REMOVE_CHARS:
+
+ result = av_strdup(text);
+ if (!result)
+ return NULL;
+
+ for (size_t n = 0; n < strlen(result); n++) {
+ int skip_char = 0;
+
+ if (result[n] == '{')
+ escape_level++;
+
+ if (!escape_level) {
+ for (size_t t = 0; t < FF_ARRAY_ELEMS(char_src); t++) {
+ if (result[n] == char_src[t]) {
+ skip_char = 1;
+ break;
+ }
+ }
+ }
+
+ if (!skip_char)
+ result[k++] = result[n];
+
+ if (result[n] == '}')
+ escape_level--;
+ }
+
+ result[k] = 0;
+
+ break;
+ case OP_REPLACE_WORDS:
+ case OP_REMOVE_WORDS:
+
+ result = av_strdup(text);
+ if (!result)
+ return NULL;
+
+ for (int n = 0; n < s->nb_find_list; n++) {
+ char *tmp = result;
+ const char *replace = (s->operation == OP_REPLACE_WORDS) ? s->replace_list[n] : "";
+
+ result = av_strireplace(result, s->find_list[n], replace);
+ if (!result)
+ return NULL;
+
+ av_free(tmp);
+ }
+
+ break;
+ }
+
+ return result;
+}
+
+static char *process_dialog(TextModContext *s, char *ass_line)
+{
+ ASSDialog *dialog = ff_ass_split_dialog(NULL, ass_line);
+ char *result, *text;
+
+ if (!dialog)
+ return NULL;
+
+ text = process_text(s, dialog->text);
+ if (!text)
+ return NULL;
+
+ result = ff_ass_get_dialog(dialog->readorder, dialog->layer, dialog->style, dialog->name, text);
+
+ av_free(text);
+ ff_ass_free_dialog(&dialog);
+ return result;
+}
+
+static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
+{
+ TextModContext *s = inlink->dst->priv;
+ AVFilterLink *outlink = inlink->dst->outputs[0];
+ int ret;
+
+ outlink->format = inlink->format;
+
+ av_frame_make_writable(frame);
+
+ if (!frame)
+ return AVERROR(ENOMEM);
+
+ for (unsigned i = 0; i < frame->num_subtitle_areas; i++) {
+
+ AVSubtitleArea *area = frame->subtitle_areas[i];
+
+ if (area->ass) {
+ char *tmp = area->ass;
+ area->ass = process_dialog(s, area->ass);
+ av_free(tmp);
+ if (!area->ass)
+ return AVERROR(ENOMEM);
+ }
+ }
+
+ return ff_filter_frame(outlink, frame);
+}
+
+#define OFFSET(x) offsetof(TextModContext, x)
+#define FLAGS (AV_OPT_FLAG_SUBTITLE_PARAM | AV_OPT_FLAG_FILTERING_PARAM)
+
+static const AVOption textmod_options[] = {
+ { "mode", "set operation mode", OFFSET(operation), AV_OPT_TYPE_INT, {.i64=OP_LEET}, OP_LEET, NB_OPS-1, FLAGS, "mode" },
+ { "leet", "convert text to 'leet speak'", 0, AV_OPT_TYPE_CONST, {.i64=OP_LEET}, 0, 0, FLAGS, "mode" },
+ { "to_upper", "change to upper case", 0, AV_OPT_TYPE_CONST, {.i64=OP_TO_UPPER}, 0, 0, FLAGS, "mode" },
+ { "to_lower", "change to lower case", 0, AV_OPT_TYPE_CONST, {.i64=OP_TO_LOWER}, 0, 0, FLAGS, "mode" },
+ { "replace_chars", "replace characters", 0, AV_OPT_TYPE_CONST, {.i64=OP_REPLACE_CHARS}, 0, 0, FLAGS, "mode" },
+ { "remove_chars", "remove characters", 0, AV_OPT_TYPE_CONST, {.i64=OP_REMOVE_CHARS}, 0, 0, FLAGS, "mode" },
+ { "replace_words", "replace words", 0, AV_OPT_TYPE_CONST, {.i64=OP_REPLACE_WORDS}, 0, 0, FLAGS, "mode" },
+ { "remove_words", "remove words", 0, AV_OPT_TYPE_CONST, {.i64=OP_REMOVE_WORDS}, 0, 0, FLAGS, "mode" },
+ { "find", "chars/words to find or remove", OFFSET(find), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS, NULL },
+ { "replace", "chars/words to replace", OFFSET(replace), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS, NULL },
+ { "separator", "word separator (default: ',')", OFFSET(separator), AV_OPT_TYPE_STRING, {.str = ","}, 0, 0, FLAGS, NULL },
+ { NULL },
+};
+
+AVFILTER_DEFINE_CLASS(textmod);
+
+static const AVFilterPad inputs[] = {
+ {
+ .name = "default",
+ .type = AVMEDIA_TYPE_SUBTITLE,
+ .filter_frame = filter_frame,
+ },
+};
+
+static const AVFilterPad outputs[] = {
+ {
+ .name = "default",
+ .type = AVMEDIA_TYPE_SUBTITLE,
+ },
+};
+
+const AVFilter ff_sf_textmod = {
+ .name = "textmod",
+ .description = NULL_IF_CONFIG_SMALL("Modify subtitle text in several ways"),
+ .init = init,
+ .uninit = uninit,
+ .query_formats = query_formats,
+ .priv_size = sizeof(TextModContext),
+ .priv_class = &textmod_class,
+ FILTER_INPUTS(inputs),
+ FILTER_OUTPUTS(outputs),
+};
--
2.30.2.windows.1
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