avfilter/af_extrastereo: add support for commands

doc/filters.texi

@@ -3558,6 +3558,10 @@ Sets the difference coefficient (default: 2.5). 0.0 means mono sound
 Enable clipping. By default is enabled.
 @end table
 
+@subsection Commands
+
+This filter supports the all above options as @ref{commands}.
+
 @section firequalizer
 Apply FIR Equalization using arbitrary frequency response.
 

libavfilter/af_extrastereo.c

@@ -31,7 +31,7 @@ typedef struct ExtraStereoContext {
 } ExtraStereoContext;
 
 #define OFFSET(x) offsetof(ExtraStereoContext, x)
-#define A AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
+#define A AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_RUNTIME_PARAM
 
 static const AVOption extrastereo_options[] = {
     { "m", "set the difference coefficient", OFFSET(mult), AV_OPT_TYPE_FLOAT, {.dbl=2.5}, -10, 10, A },
@@ -129,4 +129,5 @@ AVFilter ff_af_extrastereo = {
     .inputs         = inputs,
     .outputs        = outputs,
     .flags          = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
+    .process_command = ff_filter_process_command,
 };