lavfi: add setfield filter

1 files changed, 92 insertions, 0 deletions

diff --git a/libavfilter/vf_setfield.c b/libavfilter/vf_setfield.c
new file mode 100644
index 0000000000..bfb8006acf
--- /dev/null
+++ b/libavfilter/vf_setfield.c
@@ -0,0 +1,92 @@
+/*
+ * Copyright (c) 2012 Stefano Sabatini
+ *
+ * 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
+ * set field order
+ */
+
+#include "avfilter.h"
+
+typedef struct {
+    int top_field_first;
+} SetFieldContext;
+
+static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
+{
+    SetFieldContext *setfield = ctx->priv;
+
+    setfield->top_field_first = -1;
+
+    if (args) {
+        char c;
+        if (sscanf(args, "%d%c", &setfield->top_field_first, &c) != 1) {
+            if      (!strcmp("tff",  args)) setfield->top_field_first = 1;
+            else if (!strcmp("bff",  args)) setfield->top_field_first = 0;
+            else if (!strcmp("auto", args)) setfield->top_field_first = -1;
+            else {
+                av_log(ctx, AV_LOG_ERROR, "Invalid argument '%s'\n", args);
+                return AVERROR(EINVAL);
+            }
+        }
+    }
+
+    if (setfield->top_field_first < -1 || setfield->top_field_first > 1) {
+        av_log(ctx, AV_LOG_ERROR,
+               "Provided integer value %d must be included between -1 and +1\n",
+               setfield->top_field_first);
+        return AVERROR(EINVAL);
+    }
+
+    return 0;
+}
+
+static void start_frame(AVFilterLink *inlink, AVFilterBufferRef *inpicref)
+{
+    SetFieldContext *setfield = inlink->dst->priv;
+    AVFilterBufferRef *outpicref = avfilter_ref_buffer(inpicref, ~0);
+
+    if (setfield->top_field_first != -1) {
+        outpicref->video->interlaced = 1;
+        outpicref->video->top_field_first = setfield->top_field_first;
+    }
+    avfilter_start_frame(inlink->dst->outputs[0], outpicref);
+}
+
+AVFilter avfilter_vf_setfield = {
+    .name      = "setfield",
+    .description = NULL_IF_CONFIG_SMALL("Force field for the output video frame."),
+    .init      = init,
+
+    .priv_size = sizeof(SetFieldContext),
+
+    .inputs = (const AVFilterPad[]) {
+        { .name             = "default",
+          .type             = AVMEDIA_TYPE_VIDEO,
+          .get_video_buffer = avfilter_null_get_video_buffer,
+          .start_frame      = start_frame, },
+        { .name = NULL }
+    },
+    .outputs = (const AVFilterPad[]) {
+        { .name             = "default",
+          .type             = AVMEDIA_TYPE_VIDEO, },
+        { .name = NULL }
+    },
+};