Signed-off-by: Bernd Bleßmann <b...@it-entwicklung.de>
---
doc/filters.texi | 13 +++++++++++++
libavfilter/vf_scale.c | 43 ++++++++++++++++++++++++++++++++++---------
2 files changed, 47 insertions(+), 9 deletions(-)
diff --git a/doc/filters.texi b/doc/filters.texi
index 2b0359d..28aaef3 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -8906,6 +8906,19 @@ scale=w='min(500\, iw*3/2):h=-1'
@end example
@end itemize
+@subsection Commands
+
+This filter supports the following commands:
+@table @option
+@item width, w
+@item height, h
+Set the output video dimension expression.
+The command accepts the same syntax of the corresponding option.
+
+If the specified expression is not valid, it is kept at its current
+value.
+@end table
+
@section separatefields
The @code{separatefields} takes a frame-based video input and splits
diff --git a/libavfilter/vf_scale.c b/libavfilter/vf_scale.c
index 2a3d008..d4c0be2 100644
--- a/libavfilter/vf_scale.c
+++ b/libavfilter/vf_scale.c
@@ -544,6 +544,30 @@ static int filter_frame(AVFilterLink *link, AVFrame *in)
return ff_filter_frame(outlink, out);
}
+static int process_command(AVFilterContext *ctx, const char *cmd, const char
*args,
+ char *res, int res_len, int flags)
+{
+ ScaleContext *scale = ctx->priv;
+ int ret;
+
+ if ( !strcmp(cmd, "width") || !strcmp(cmd, "w")
+ || !strcmp(cmd, "height") || !strcmp(cmd, "h")) {
+
+ int old_w = scale->w;
+ int old_h = scale->h;
+ AVFilterLink *outlink = ctx->outputs[0];
+
+ av_opt_set(scale, cmd, args, 0);
+ if ((ret = config_props(outlink)) < 0) {
+ scale->w = old_w;
+ scale->h = old_h;
+ }
+ } else
+ ret = AVERROR(ENOSYS);
+
+ return ret;
+}
+
static const AVClass *child_class_next(const AVClass *prev)
{
return prev ? NULL : sws_get_class();
@@ -610,13 +634,14 @@ static const AVFilterPad avfilter_vf_scale_outputs[] = {
};
AVFilter ff_vf_scale = {
- .name = "scale",
- .description = NULL_IF_CONFIG_SMALL("Scale the input video size and/or
convert the image format."),
- .init_dict = init_dict,
- .uninit = uninit,
- .query_formats = query_formats,
- .priv_size = sizeof(ScaleContext),
- .priv_class = &scale_class,
- .inputs = avfilter_vf_scale_inputs,
- .outputs = avfilter_vf_scale_outputs,
+ .name = "scale",
+ .description = NULL_IF_CONFIG_SMALL("Scale the input video size and/or
convert the image format."),
+ .init_dict = init_dict,
+ .uninit = uninit,
+ .query_formats = query_formats,
+ .priv_size = sizeof(ScaleContext),
+ .priv_class = &scale_class,
+ .inputs = avfilter_vf_scale_inputs,
+ .outputs = avfilter_vf_scale_outputs,
+ .process_command = process_command,
};
--
2.1.4
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