[FFmpeg-devel] [PATCH 2/9] avfilter/subtitles: Add subtitles.c

[Soft Works]

Signed-off-by: softworkz <softworkz at hotmail.com>
---
 libavfilter/Makefile    |  1 +
 libavfilter/internal.h  |  8 ++++++
 libavfilter/subtitles.c | 61 +++++++++++++++++++++++++++++++++++++++++
 libavfilter/subtitles.h | 42 ++++++++++++++++++++++++++++
 4 files changed, 112 insertions(+)
 create mode 100644 libavfilter/subtitles.c
 create mode 100644 libavfilter/subtitles.h

diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index 102ce7beff..db32cf1265 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -19,6 +19,7 @@ OBJS = allfilters.o                                                     \
        framequeue.o                                                     \
        graphdump.o                                                      \
        graphparser.o                                                    \
+       subtitles.o                                                          \
        video.o                                                          \
 
 OBJS-$(HAVE_THREADS)                         += pthread.o
diff --git a/libavfilter/internal.h b/libavfilter/internal.h
index a0aa32af4d..4f9aedf151 100644
--- a/libavfilter/internal.h
+++ b/libavfilter/internal.h
@@ -87,6 +87,14 @@ struct AVFilterPad {
         AVFrame *(*audio)(AVFilterLink *link, int nb_samples);
     } get_buffer;
 
+    /**
+     * Callback function to get a subtitle buffer. If NULL, the filter system will
+     * use ff_default_get_subtitle_buffer().
+     *
+     * Input subtitle pads only.
+     */
+    AVFrame *(*get_subtitle_buffer)(AVFilterLink *link, int format);
+
     /**
      * Filtering callback. This is where a filter receives a frame with
      * audio/video data and should do its processing.
diff --git a/libavfilter/subtitles.c b/libavfilter/subtitles.c
new file mode 100644
index 0000000000..188ff1289c
--- /dev/null
+++ b/libavfilter/subtitles.c
@@ -0,0 +1,61 @@
+/*
+ * 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
+ */
+
+#include "libavutil/common.h"
+
+#include "subtitles.h"
+#include "avfilter.h"
+#include "internal.h"
+
+
+AVFrame *ff_null_get_subtitles_buffer(AVFilterLink *link, int format)
+{
+    return ff_get_subtitles_buffer(link->dst->outputs[0], format);
+}
+
+AVFrame *ff_default_get_subtitles_buffer(AVFilterLink *link, int format)
+{
+    AVFrame *frame = NULL;
+
+    // TODO:
+    //frame = ff_frame_pool_get(link->frame_pool);
+
+    frame = av_frame_alloc();
+    if (!frame)
+        return NULL;
+
+    frame->format = format;
+    frame->type = AVMEDIA_TYPE_SUBTITLE;
+
+    return frame;
+}
+
+AVFrame *ff_get_subtitles_buffer(AVFilterLink *link, int format)
+{
+    AVFrame *ret = NULL;
+
+    if (link->dstpad->get_subtitle_buffer)
+        ret = link->dstpad->get_subtitle_buffer(link, format);
+
+    if (!ret)
+        ret = ff_default_get_subtitles_buffer(link, format);
+
+    return ret;
+}
diff --git a/libavfilter/subtitles.h b/libavfilter/subtitles.h
new file mode 100644
index 0000000000..b964b61c37
--- /dev/null
+++ b/libavfilter/subtitles.h
@@ -0,0 +1,42 @@
+/*
+ * 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
+ */
+
+#ifndef AVFILTER_SUBTITLES_H
+#define AVFILTER_SUBTITLES_H
+
+#include "avfilter.h"
+#include "internal.h"
+
+/** default handler for get_subtitles_buffer() for subtitle inputs */
+AVFrame *ff_default_get_subtitles_buffer(AVFilterLink *link, int format);
+
+/** get_subtitles_buffer() handler for filters which simply pass subtitles along */
+AVFrame *ff_null_get_subtitles_buffer(AVFilterLink *link, int format);
+
+/**
+ * Request a subtitles buffer with a specific set of permissions.
+ *
+ * @param link           the output link to the filter from which the buffer will
+ *                       be requested
+ * @return               The subtitles format.
+ */
+AVFrame *ff_get_subtitles_buffer(AVFilterLink *link, int format);
+
+#endif /* AVFILTER_SUBTITLES_H */
-- 
2.28.0.windows.1