avfilter/aformat: add shorthand names for options

doc/filters.texi

@@ -1285,13 +1285,13 @@ negotiate the most appropriate format to minimize conversions.
 It accepts the following parameters:
 @table @option
 
-@item sample_fmts
+@item sample_fmts, f
 A '|'-separated list of requested sample formats.
 
-@item sample_rates
+@item sample_rates, r
 A '|'-separated list of requested sample rates.
 
-@item channel_layouts
+@item channel_layouts, cl
 A '|'-separated list of requested channel layouts.
 
 See @ref{channel layout syntax,,the Channel Layout section in the ffmpeg-utils(1) manual,ffmpeg-utils}

libavfilter/af_aformat.c

@@ -50,8 +50,11 @@ typedef struct AFormatContext {
 #define F AV_OPT_FLAG_FILTERING_PARAM
 static const AVOption aformat_options[] = {
     { "sample_fmts",     "A '|'-separated list of sample formats.",  OFFSET(formats_str),         AV_OPT_TYPE_STRING, .flags = A|F },
+    { "f",               "A '|'-separated list of sample formats.",  OFFSET(formats_str),         AV_OPT_TYPE_STRING, .flags = A|F },
     { "sample_rates",    "A '|'-separated list of sample rates.",    OFFSET(sample_rates_str),    AV_OPT_TYPE_STRING, .flags = A|F },
+    { "r",               "A '|'-separated list of sample rates.",    OFFSET(sample_rates_str),    AV_OPT_TYPE_STRING, .flags = A|F },
     { "channel_layouts", "A '|'-separated list of channel layouts.", OFFSET(channel_layouts_str), AV_OPT_TYPE_STRING, .flags = A|F },
+    { "cl",              "A '|'-separated list of channel layouts.", OFFSET(channel_layouts_str), AV_OPT_TYPE_STRING, .flags = A|F },
     { NULL }
 };