avfilter/scale: refactor common code for scaling height/width expressions

Implements support for height/width expressions in vf_scale_vaapi,
by refactoring common code into a new libavfilter/scale.c

Signed-off-by: Mark Thompson <sw@jkqxz.net>

1 files changed, 28 insertions, 0 deletions

diff --git a/libavfilter/scale.h b/libavfilter/scale.h
new file mode 100644
index 0000000000..dfe67d0be0
--- /dev/null
+++ b/libavfilter/scale.h
@@ -0,0 +1,28 @@
+/*
+ * 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_SCALE_H
+#define AVFILTER_SCALE_H
+
+#include "avfilter.h"
+
+int ff_scale_eval_dimensions(void *ctx,
+    const char *w_expr, const char *h_expr,
+    AVFilterLink *inlink, AVFilterLink *outlink,
+    int *ret_w, int *ret_h);
+#endif