lavfi/aspect: add max option

doc/filters.texi

@@ -3256,6 +3256,10 @@ named options, expressed as a sequence of @var{key}=@var{value} pairs,
 separated by ":".
 
 @table @option
+@item max
+Set the maximum integer value to use for expressing numerator and
+denominator when reducing the expressed aspect ratio to a rational.
+Default value is @code{100}.
 
 @item r, ratio:
 Set the aspect ratio used by the filter.
@@ -3268,6 +3272,9 @@ In case the form "@var{num}:@var{den}" the @code{:} character should
 be escaped.
 @end table
 
+If the keys are omitted in the named options list, the specifed values
+are assumed to be @var{ratio} and @var{max} in that order.
+
 For example to change the display aspect ratio to 16:9, specify:
 @example
 setdar='16:9'
@@ -3283,6 +3290,12 @@ To change the sample aspect ratio to 10:11, specify:
 setsar='10:11'
 @end example
 
+To set a display aspect ratio of 16:9, and specify a maximum integer value of
+1000 in the aspect ratio reduction, use the command:
+@example
+setdar=ratio='16:9':max=1000
+@end example
+
 @section setfield
 
 Force field for the output video frame.

libavfilter/version.h

@@ -30,7 +30,7 @@
 
 #define LIBAVFILTER_VERSION_MAJOR  3
 #define LIBAVFILTER_VERSION_MINOR  20
-#define LIBAVFILTER_VERSION_MICRO 103
+#define LIBAVFILTER_VERSION_MICRO 104
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
                                                LIBAVFILTER_VERSION_MINOR, \

libavfilter/vf_aspect.c

@@ -35,12 +35,14 @@ typedef struct {
     const AVClass *class;
     AVRational ratio;
     char *ratio_str;
+    int max;
 } AspectContext;
 
 #define OFFSET(x) offsetof(AspectContext, x)
 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
 
 static const AVOption options[] = {
+    {"max", "set max value for nominator or denominator in the ratio", OFFSET(max), AV_OPT_TYPE_INT, {.i64=100}, 1, INT_MAX, FLAGS },
     {"ratio", "set ratio", OFFSET(ratio_str), AV_OPT_TYPE_STRING, {.str="0"}, 0, 0, FLAGS },
     {"r",     "set ratio", OFFSET(ratio_str), AV_OPT_TYPE_STRING, {.str="0"}, 0, 0, FLAGS },
     {NULL}
@@ -49,7 +51,7 @@ static const AVOption options[] = {
 static av_cold int init(AVFilterContext *ctx, const char *args, const AVClass *class)
 {
     AspectContext *aspect = ctx->priv;
-    static const char *shorthand[] = { "ratio", NULL };
+    static const char *shorthand[] = { "ratio", "max", NULL };
     char c;
     int ret;
     AVRational q;
@@ -66,7 +68,7 @@ static av_cold int init(AVFilterContext *ctx, const char *args, const AVClass *c
     }
 
     if (aspect->ratio_str) {
-        ret = av_parse_ratio(&aspect->ratio, aspect->ratio_str, 100, 0, ctx);
+        ret = av_parse_ratio(&aspect->ratio, aspect->ratio_str, aspect->max, 0, ctx);
         if (ret < 0 || aspect->ratio.num < 0 || aspect->ratio.den <= 0) {
             av_log(ctx, AV_LOG_ERROR,
                    "Invalid string '%s' for aspect ratio\n", args);