[FFmpeg-devel] [PATCH v3 08/26] avfilter/subtitles: Add subtitles.c for subtitle frame allocation

[ffmpegagent]

From: softworkz <softworkz at hotmail.com>

Analog to avfilter/video.c and avfilter/audio.c

Signed-off-by: softworkz <softworkz at hotmail.com>
---
 libavfilter/Makefile    |  1 +
 libavfilter/avfilter.c  |  4 +++
 libavfilter/internal.h  |  1 +
 libavfilter/subtitles.c | 63 +++++++++++++++++++++++++++++++++++++++++
 libavfilter/subtitles.h | 44 ++++++++++++++++++++++++++++
 5 files changed, 113 insertions(+)
 create mode 100644 libavfilter/subtitles.c
 create mode 100644 libavfilter/subtitles.h

diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index 282967144b..f1176644c9 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/avfilter.c b/libavfilter/avfilter.c
index 7362bcdab5..df5b8f483c 100644
--- a/libavfilter/avfilter.c
+++ b/libavfilter/avfilter.c
@@ -43,6 +43,7 @@
 #include "formats.h"
 #include "framepool.h"
 #include "internal.h"
+#include "subtitles.h"
 
 #include "libavutil/ffversion.h"
 const char av_filter_ffversion[] = "FFmpeg version " FFMPEG_VERSION;
@@ -1475,6 +1476,9 @@ int ff_inlink_make_frame_writable(AVFilterLink *link, AVFrame **rframe)
     case AVMEDIA_TYPE_AUDIO:
         out = ff_get_audio_buffer(link, frame->nb_samples);
         break;
+    case AVMEDIA_TYPE_SUBTITLE:
+        out = ff_get_subtitles_buffer(link, link->format);
+        break;
     default:
         return AVERROR(EINVAL);
     }
diff --git a/libavfilter/internal.h b/libavfilter/internal.h
index 1099b82b4b..fc09ef574c 100644
--- a/libavfilter/internal.h
+++ b/libavfilter/internal.h
@@ -90,6 +90,7 @@ struct AVFilterPad {
     union {
         AVFrame *(*video)(AVFilterLink *link, int w, int h);
         AVFrame *(*audio)(AVFilterLink *link, int nb_samples);
+        AVFrame *(*subtitle)(AVFilterLink *link, int format);
     } get_buffer;
 
     /**
diff --git a/libavfilter/subtitles.c b/libavfilter/subtitles.c
new file mode 100644
index 0000000000..951bfd612c
--- /dev/null
+++ b/libavfilter/subtitles.c
@@ -0,0 +1,63 @@
+/*
+ * 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;
+
+    frame = av_frame_alloc();
+    if (!frame)
+        return NULL;
+
+    frame->format = format;
+    frame->type = AVMEDIA_TYPE_SUBTITLE;
+
+    if (av_frame_get_buffer2(frame, 0) < 0) {
+        av_frame_free(&frame);
+        return NULL;
+    }
+
+    return frame;
+}
+
+AVFrame *ff_get_subtitles_buffer(AVFilterLink *link, int format)
+{
+    AVFrame *ret = NULL;
+
+    if (link->dstpad->get_buffer.subtitle)
+        ret = link->dstpad->get_buffer.subtitle(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..4a9115126e
--- /dev/null
+++ b/libavfilter/subtitles.h
@@ -0,0 +1,44 @@
+/*
+ * 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 frame with a specific set of permissions.
+ *
+ * @param link           the output link to the filter from which the buffer will
+ *                       be requested
+ * @param format         The subtitles format.
+ * @return               A reference to the frame. This must be unreferenced with
+ *                       av_frame_free when you are finished with it.
+*/
+AVFrame *ff_get_subtitles_buffer(AVFilterLink *link, int format);
+
+#endif /* AVFILTER_SUBTITLES_H */
-- 
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