@@ -6373,6 +6373,33 @@ Full range (0-255 in case of 8bit luma)

 "Mpeg" range (16-235 in case of 8bit luma)

 @end table

+@item force_original_aspect_ratio

+Enable decreasing or increasing output video width or height if necessary to

+keep the original aspect ratio. Possible values:

+

+@table @samp

+@item disable

+Scale the video as specified and disable this feature.

+

+@item decrease

+The output video dimensions will automatically be decreased if needed.

+

+@item increase

+The output video dimensions will automatically be increased if needed.

+

+@end table

+

+One useful instance of this option is that when you know a specific device's

+maximum allowed resolution, you can use this to limit the output video to

+that, while retaining the aspect ratio. For example, device A allows

+1280x720 playback, and your video is 1920x800. Using this option (set it to

+decrease) and specifying 1280x720 to the command line makes the output

+1280x533.

+

+Please note that this is a different thing than specifying -1 for @option{w}

+or @option{h}, you still need to specify the output resolution for this option

+to work.

+

 @end table

 The values of the @var{w} and @var{h} options are expressions

@@ -101,6 +101,8 @@ typedef struct {

     int out_v_chr_pos;

     int in_h_chr_pos;

     int in_v_chr_pos;

+

+    int force_original_aspect_ratio;

 } ScaleContext;

 static av_cold int init(AVFilterContext *ctx)

@@ -274,6 +276,19 @@ static int config_props(AVFilterLink *outlink)

     if (h == -1)

         h = av_rescale(w, inlink->h, inlink->w);

+    if (scale->force_original_aspect_ratio) {

+        int tmp_w = av_rescale(h, inlink->w, inlink->h);

+        int tmp_h = av_rescale(w, inlink->h, inlink->w);

+

+        if (scale->force_original_aspect_ratio == 1) {

+             w = FFMIN(tmp_w, w);

+             h = FFMIN(tmp_h, h);

+        } else {

+             w = FFMAX(tmp_w, w);

+             h = FFMAX(tmp_h, h);

+        }

+    }

+

     if (w > INT_MAX || h > INT_MAX ||

         (h * inlink->w) > INT_MAX  ||

         (w * inlink->h) > INT_MAX)

@@ -501,6 +516,10 @@ static const AVOption scale_options[] = {

     { "in_h_chr_pos",   "input horizontal chroma position in luma grid/256", OFFSET(in_h_chr_pos), AV_OPT_TYPE_INT, { .i64 = -1}, -1, 512, FLAGS },

     { "out_v_chr_pos",   "output vertical chroma position in luma grid/256"  , OFFSET(out_v_chr_pos), AV_OPT_TYPE_INT, { .i64 = -1}, -1, 512, FLAGS },

     { "out_h_chr_pos",   "output horizontal chroma position in luma grid/256", OFFSET(out_h_chr_pos), AV_OPT_TYPE_INT, { .i64 = -1}, -1, 512, FLAGS },

+    { "force_original_aspect_ratio", "decrease or increase w/h if necessary to keep the original AR", OFFSET(force_original_aspect_ratio), AV_OPT_TYPE_INT, { .i64 = 0}, 0, 2, FLAGS, "force_oar" },

+    { "disable",  NULL, 0, AV_OPT_TYPE_CONST, {.i64 = 0 }, 0, 0, FLAGS, "force_oar" },

+    { "decrease", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = 1 }, 0, 0, FLAGS, "force_oar" },

+    { "increase", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = 2 }, 0, 0, FLAGS, "force_oar" },

     { NULL },

 };