video: switch from using display aspect to sample aspect

MPlayer traditionally always used the display aspect ratio, e.g. 16:9,
while FFmpeg uses the sample (aka pixel) aspect ratio.

Both have a bunch of advantages and disadvantages. Actually, it seems
using sample aspect ratio is generally nicer. The main reason for the
change is making mpv closer to how FFmpeg works in order to make life
easier. It's also nice that everything uses integer fractions instead
of floats now (except --video-aspect option/property).

Note that there is at least 1 user-visible change: vf_dsize now does
not set the display size, only the display aspect ratio. This is
because the image_params d_w/d_h fields did not just set the display
aspect, but also the size (except in encoding mode).

1 files changed, 7 insertions, 34 deletions

diff --git a/video/filter/vf_lavfi.c b/video/filter/vf_lavfi.c
index a64738d355..16aeb52338 100644
--- a/video/filter/vf_lavfi.c
+++ b/video/filter/vf_lavfi.c
@@ -103,30 +103,7 @@ static void destroy_graph(struct vf_instance *vf)
     p->eof = false;
 }
 
-static AVRational par_from_sar_dar(int width, int height,
-                                   int d_width, int d_height)
-{
-    return av_div_q((AVRational){d_width, d_height},
-                    (AVRational){width, height});
-}
-
-static void dar_from_sar_par(int width, int height, AVRational par,
-                             int *out_dw, int *out_dh)
-{
-    *out_dw = width;
-    *out_dh = height;
-    if (par.num != 0 && par.den != 0) {
-        double d = av_q2d(par);
-        if (d > 1.0) {
-            *out_dw = floor(*out_dw * d + 0.5);
-        } else {
-            *out_dh = floor(*out_dh / d + 0.5);
-        }
-    }
-}
-
-static bool recreate_graph(struct vf_instance *vf, int width, int height,
-                           int d_width, int d_height, unsigned int fmt)
+static bool recreate_graph(struct vf_instance *vf, struct mp_image_params *fmt)
 {
     void *tmp = talloc_new(NULL);
     struct vf_priv_s *p = vf->priv;
@@ -168,13 +145,12 @@ static bool recreate_graph(struct vf_instance *vf, int width, int height,
     char *sws_flags = talloc_asprintf(tmp, "flags=%"PRId64, p->cfg_sws_flags);
     graph->scale_sws_opts = av_strdup(sws_flags);
 
-    AVRational par = par_from_sar_dar(width, height, d_width, d_height);
     AVRational timebase = AV_TIME_BASE_Q;
 
     char *src_args = talloc_asprintf(tmp, "%d:%d:%d:%d:%d:%d:%d",
-                                     width, height, imgfmt2pixfmt(fmt),
+                                     fmt->w, fmt->h, imgfmt2pixfmt(fmt->imgfmt),
                                      timebase.num, timebase.den,
-                                     par.num, par.den);
+                                     fmt->p_w, fmt->p_h);
 
     if (avfilter_graph_create_filter(&in, avfilter_get_by_name("buffer"),
                                      "src", src_args, NULL, graph) < 0)
@@ -225,7 +201,7 @@ static void reset(vf_instance_t *vf)
     struct vf_priv_s *p = vf->priv;
     struct mp_image_params *f = &vf->fmt_in;
     if (p->graph && f->imgfmt)
-        recreate_graph(vf, f->w, f->h, f->d_w, f->d_h, f->imgfmt);
+        recreate_graph(vf, f);
 }
 
 static int reconfig(struct vf_instance *vf, struct mp_image_params *in,
@@ -240,7 +216,7 @@ static int reconfig(struct vf_instance *vf, struct mp_image_params *in,
             return -1;
     }
 
-    if (!recreate_graph(vf, in->w, in->h, in->d_w, in->d_h, in->imgfmt))
+    if (!recreate_graph(vf, in))
         return -1;
 
     AVFilterLink *l_out = p->out->inputs[0];
@@ -251,13 +227,10 @@ static int reconfig(struct vf_instance *vf, struct mp_image_params *in,
 
     p->par_in = l_in->sample_aspect_ratio;
 
-    int dw, dh;
-    dar_from_sar_par(l_out->w, l_out->h, l_out->sample_aspect_ratio, &dw, &dh);
-
     out->w = l_out->w;
     out->h = l_out->h;
-    out->d_w = dw;
-    out->d_h = dh;
+    out->p_w = l_out->sample_aspect_ratio.num;
+    out->p_h = l_out->sample_aspect_ratio.den;
     out->imgfmt = pixfmt2imgfmt(l_out->format);
     return 0;
 }