From: Linjie Fu <linjie.justin...@gmail.com>
To pass the swscale options for the inserted scalers.
ffmpeg -i input.mp4 -filter_complex \
"scale_sws_opts=alphablend=checkerboard;format=nv12" \
-t 0.5 output.mp4
Update docs.
Signed-off-by: Linjie Fu <linjie.justin...@gmail.com>
---
doc/filters.texi | 7 ++++---
libavfilter/graphparser.c | 27 +++++++++++++++++++++++++++
2 files changed, 31 insertions(+), 3 deletions(-)
diff --git a/doc/filters.texi b/doc/filters.texi
index 790d165433..dbbb3a6940 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -204,9 +204,9 @@ pads must be connected. A filtergraph is considered valid
if all the
filter input and output pads of all the filterchains are connected.
Libavfilter will automatically insert @ref{scale} filters where format
-conversion is required. It is possible to specify swscale flags
-for those automatically inserted scalers by prepending
-@code{sws_flags=@var{flags};}
+conversion is required. It is possible to specify swscale flags or
+scale_sws_opts for those automatically inserted scalers by prepending
+@code{sws_flags=@var{flags};} or @code{scale_sws_opts=@var{scale_sws_opts};}
to the filtergraph description.
Here is a BNF description of the filtergraph syntax:
@@ -219,6 +219,7 @@ Here is a BNF description of the filtergraph syntax:
@var{FILTER} ::= [@var{LINKLABELS}] @var{FILTER_NAME} ["="
@var{FILTER_ARGUMENTS}] [@var{LINKLABELS}]
@var{FILTERCHAIN} ::= @var{FILTER} [,@var{FILTERCHAIN}]
@var{FILTERGRAPH} ::= [sws_flags=@var{flags};] @var{FILTERCHAIN}
[;@var{FILTERGRAPH}]
+@var{FILTERGRAPH} ::= [scale_sws_opts=@var{opts};] @var{FILTERCHAIN}
[;@var{FILTERGRAPH}]
@end example
@anchor{filtergraph escaping}
diff --git a/libavfilter/graphparser.c b/libavfilter/graphparser.c
index 1385c3ae71..8c63d6454e 100644
--- a/libavfilter/graphparser.c
+++ b/libavfilter/graphparser.c
@@ -415,6 +415,30 @@ static int parse_sws_flags(const char **buf, AVFilterGraph
*graph)
return 0;
}
+static int parse_scale_sws_opts(const char **buf, AVFilterGraph *graph)
+{
+ char *p = strchr(*buf, ';');
+
+ if (strncmp(*buf, "scale_sws_opts=", 15)) {
+ return 0;
+ }
+
+ if (!p) {
+ av_log(graph, AV_LOG_ERROR, "scale_sws_opts not terminated with
';'.\n");
+ return AVERROR(EINVAL);
+ }
+
+ *buf += 15;
+
+ av_freep(&graph->scale_sws_opts);
+ if (!(graph->scale_sws_opts = av_mallocz(p - *buf + 1)))
+ return AVERROR(ENOMEM);
+ av_strlcpy(graph->scale_sws_opts, *buf, p - *buf + 1);
+
+ *buf = p + 1;
+ return 0;
+}
+
int avfilter_graph_parse2(AVFilterGraph *graph, const char *filters,
AVFilterInOut **inputs,
AVFilterInOut **outputs)
@@ -429,6 +453,9 @@ int avfilter_graph_parse2(AVFilterGraph *graph, const char
*filters,
if ((ret = parse_sws_flags(&filters, graph)) < 0)
goto fail;
+ if ((ret = parse_scale_sws_opts(&filters, graph)) < 0)
+ goto fail;
+
do {
AVFilterContext *filter;
filters += strspn(filters, WHITESPACES);
--
2.31.1
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