vf: redo conversion filter insertion/format negotiation

Remove the inconsistent, duplicated, and insufficient scale filter
insertion code, and do it in one place instead. This also compensates
for the earlier removal of vf_match_csp() (which was in fact duplicated
code).

The algorithm to determine where to insert a filter etc. is probably the
same, though it also comes with some changes that should make debugging
easier when trying to figure out why a chain is failing to configure.

Add an "in" pseudo filter, which makes insertion of conversion filters
easier. Also change the vf->reconfig signature. At a later point, I'll
probably change format negotiation such that the generic filter code
will choose the output format, so having separate in and out params will
be useful.

1 files changed, 19 insertions, 23 deletions

diff --git a/video/filter/vf_scale.c b/video/filter/vf_scale.c
index c466c5d39a..268e65ae59 100644
--- a/video/filter/vf_scale.c
+++ b/video/filter/vf_scale.c
@@ -217,13 +217,13 @@ static unsigned int find_best_out(vf_instance_t *vf, int in_format)
     return best;
 }
 
-static int reconfig(struct vf_instance *vf, struct mp_image_params *p, int flags)
+static int reconfig(struct vf_instance *vf, struct mp_image_params *in,
+                    struct mp_image_params *out)
 {
-    int width = p->w, height = p->h, d_width = p->d_w, d_height = p->d_h;
-    unsigned int outfmt = p->imgfmt;
+    int width = in->w, height = in->h, d_width = in->d_w, d_height = in->d_h;
+    unsigned int outfmt = in->imgfmt;
     unsigned int best = find_best_out(vf, outfmt);
     int round_w = 0, round_h = 0;
-    struct mp_image_params input = *p;
 
     if (!best) {
         mp_msg(MSGT_VFILTER, MSGL_WARN,
@@ -302,30 +302,30 @@ static int reconfig(struct vf_instance *vf, struct mp_image_params *p, int flags
         d_height = vf->priv->w * d_height / d_width;
         d_width = vf->priv->w;
     }
-    //d_width=d_width*vf->priv->w/width;
-    //d_height=d_height*vf->priv->h/height;
-    p->w = vf->priv->w;
-    p->h = vf->priv->h;
-    p->d_w = d_width;
-    p->d_h = d_height;
-    p->imgfmt = best;
+
+    *out = *in;
+    out->w = vf->priv->w;
+    out->h = vf->priv->h;
+    out->d_w = d_width;
+    out->d_h = d_height;
+    out->imgfmt = best;
 
     // Second-guess what libswscale is going to output and what not.
     // It depends what libswscale supports for in/output, and what makes sense.
-    struct mp_imgfmt_desc s_fmt = mp_imgfmt_get_desc(input.imgfmt);
-    struct mp_imgfmt_desc d_fmt = mp_imgfmt_get_desc(p->imgfmt);
+    struct mp_imgfmt_desc s_fmt = mp_imgfmt_get_desc(in->imgfmt);
+    struct mp_imgfmt_desc d_fmt = mp_imgfmt_get_desc(out->imgfmt);
     // keep colorspace settings if the data stays in yuv
     if (!(s_fmt.flags & MP_IMGFLAG_YUV) || !(d_fmt.flags & MP_IMGFLAG_YUV)) {
-        p->colorspace = MP_CSP_AUTO;
-        p->colorlevels = MP_CSP_LEVELS_AUTO;
+        out->colorspace = MP_CSP_AUTO;
+        out->colorlevels = MP_CSP_LEVELS_AUTO;
     }
-    mp_image_params_guess_csp(p);
+    mp_image_params_guess_csp(out);
 
     mp_sws_set_from_cmdline(vf->priv->sws);
     vf->priv->sws->flags |= vf->priv->v_chr_drop << SWS_SRC_V_CHR_DROP_SHIFT;
     vf->priv->sws->flags |= vf->priv->accurate_rnd * SWS_ACCURATE_RND;
-    vf->priv->sws->src = input;
-    vf->priv->sws->dst = *p;
+    vf->priv->sws->src = *in;
+    vf->priv->sws->dst = *out;
 
     if (mp_sws_reinit(vf->priv->sws) < 0) {
         // error...
@@ -333,11 +333,7 @@ static int reconfig(struct vf_instance *vf, struct mp_image_params *p, int flags
                "Couldn't init libswscale for this setup\n");
         return -1;
     }
-
-    // In particular, fix up colorspace/levels if YUV<->RGB conversion is
-    // performed.
-
-    return vf_next_reconfig(vf, p, flags);
+    return 0;
 }
 
 static struct mp_image *filter(struct vf_instance *vf, struct mp_image *mpi)