vf_sub: allow more formats, simplify code

In theory, vf_sub could take any format supported by swscale. But to be
sure that it's reasonably fast, only 420P was allowed. However, other
similar 8 bit planar formats will be just as fast and there's no reason
to exclude them. Even for completely different formats there doesn't
seem to be any significant advantage to force vf_sub to convert to a
simpler/more common format.

video/filter/vf_sub.c

@@ -37,6 +37,7 @@
 #include "sub/sub.h"
 #include "sub/dec_sub.h"
 
+#include "video/sws_utils.h"
 #include "video/memcpy_pic.h"
 #include "video/csputils.h"
 
@@ -45,9 +46,9 @@
 
 static const struct vf_priv_s {
     int opt_top_margin, opt_bottom_margin;
+
     int outh, outw;
 
-    unsigned int outfmt;
     struct mp_csp_details csp;
 
     struct osd_state *osd;
@@ -60,8 +61,6 @@ static int config(struct vf_instance *vf,
                   int width, int height, int d_width, int d_height,
                   unsigned int flags, unsigned int outfmt)
 {
-    struct MPOpts *opts = vf->opts;
-
     vf->priv->outh = height + vf->priv->opt_top_margin +
                      vf->priv->opt_bottom_margin;
     vf->priv->outw = width;
@@ -69,10 +68,8 @@ static int config(struct vf_instance *vf,
     double dar = (double)d_width / d_height;
     double sar = (double)width / height;
 
-    if (!opts->screen_size_x && !opts->screen_size_y) {
-        d_width = d_width * vf->priv->outw / width;
-        d_height = d_height * vf->priv->outh / height;
-    }
+    vf_rescale_dsize(vf, &d_width, &d_height, width, height,
+                     vf->priv->outw, vf->priv->outh);
 
     vf->priv->dim = (struct mp_osd_res) {
         .w = vf->priv->outw,
@@ -87,67 +84,16 @@ static int config(struct vf_instance *vf,
 			  d_height, flags, outfmt);
 }
 
-static void blank(mp_image_t *mpi, int y1, int y2)
-{
-    int color[3] = {16, 128, 128};    // black (YUV)
-    int y;
-    unsigned char *dst;
-    int chroma_rows = (y2 - y1) >> mpi->chroma_y_shift;
-
-    dst = mpi->planes[0] + y1 * mpi->stride[0];
-    for (y = 0; y < y2 - y1; ++y) {
-        memset(dst, color[0], mpi->w);
-        dst += mpi->stride[0];
-    }
-    dst = mpi->planes[1] + (y1 >> mpi->chroma_y_shift) * mpi->stride[1];
-    for (y = 0; y < chroma_rows; ++y) {
-        memset(dst, color[1], mpi->chroma_width);
-        dst += mpi->stride[1];
-    }
-    dst = mpi->planes[2] + (y1 >> mpi->chroma_y_shift) * mpi->stride[2];
-    for (y = 0; y < chroma_rows; ++y) {
-        memset(dst, color[2], mpi->chroma_width);
-        dst += mpi->stride[2];
-    }
-}
-
 static void prepare_image(struct vf_instance *vf, struct mp_image *dmpi,
                           struct mp_image *mpi)
 {
-    int tmargin = vf->priv->opt_top_margin;
-    // copy mpi->dmpi...
-    if (mpi->flags & MP_IMGFLAG_PLANAR) {
-        memcpy_pic(dmpi->planes[0] + tmargin * dmpi->stride[0],
-                   mpi->planes[0],
-		   mpi->w,
-		   mpi->h,
-                   dmpi->stride[0],
-		   mpi->stride[0]);
-        memcpy_pic(dmpi->planes[1] + (tmargin >> mpi->chroma_y_shift) * dmpi->stride[1],
-                   mpi->planes[1],
-		   mpi->w >> mpi->chroma_x_shift,
-		   mpi->h >> mpi->chroma_y_shift,
-                   dmpi->stride[1],
-		   mpi->stride[1]);
-        memcpy_pic(dmpi->planes[2] + (tmargin >> mpi->chroma_y_shift) * dmpi->stride[2],
-                   mpi->planes[2],
-		   mpi->w >> mpi->chroma_x_shift,
-		   mpi->h >> mpi->chroma_y_shift,
-                   dmpi->stride[2],
-		   mpi->stride[2]);
-    } else {
-        memcpy_pic(dmpi->planes[0] + tmargin * dmpi->stride[0],
-                   mpi->planes[0],
-		   mpi->w * (dmpi->bpp / 8),
-		   mpi->h,
-                   dmpi->stride[0],
-		   mpi->stride[0]);
-    }
-    if (tmargin)
-        blank(dmpi, 0, tmargin);
-    if (vf->priv->opt_bottom_margin)
-        blank(dmpi, vf->priv->outh - vf->priv->opt_bottom_margin,
-              vf->priv->outh);
+    int y1 = MP_ALIGN_DOWN(vf->priv->opt_top_margin, mpi->fmt.align_y);
+    int y2 = MP_ALIGN_DOWN(y1 + mpi->h, mpi->fmt.align_y);
+    struct mp_image cropped = *dmpi;
+    mp_image_crop(&cropped, 0, y1, mpi->w, y1 + mpi->h);
+    mp_image_copy(&cropped, mpi);
+    mp_image_clear(dmpi, 0, 0, dmpi->w, y1);
+    mp_image_clear(dmpi, 0, y2, dmpi->w, vf->priv->outh);
 }
 
 static struct mp_image *filter(struct vf_instance *vf, struct mp_image *mpi)
@@ -173,11 +119,9 @@ static struct mp_image *filter(struct vf_instance *vf, struct mp_image *mpi)
 
 static int query_format(struct vf_instance *vf, unsigned int fmt)
 {
-    switch (fmt) {
-    case IMGFMT_420P:
-        return vf_next_query_format(vf, vf->priv->outfmt);
-    }
-    return 0;
+    if (!mp_sws_supported_format(fmt))
+        return 0;
+    return vf_next_query_format(vf, fmt);
 }
 
 static int control(vf_instance_t *vf, int request, void *data)
@@ -202,19 +146,8 @@ static void uninit(struct vf_instance *vf)
     free(vf->priv);
 }
 
-static const unsigned int fmt_list[] = {
-    IMGFMT_420P,
-    0
-};
-
 static int vf_open(vf_instance_t *vf, char *args)
 {
-    vf->priv->outfmt = vf_match_csp(&vf->next, fmt_list, IMGFMT_420P);
-    if (!vf->priv->outfmt) {
-        uninit(vf);
-        return 0;
-    }
-
     vf->config = config;
     vf->query_format = query_format;
     vf->uninit    = uninit;
@@ -230,7 +163,7 @@ static const m_option_t vf_opts_fields[] = {
      CONF_TYPE_INT, M_OPT_RANGE, 0, 2000},
     {"top-margin", ST_OFF(opt_top_margin),
      CONF_TYPE_INT, M_OPT_RANGE, 0, 2000},
-    {NULL, NULL, 0, 0, 0, 0, NULL}
+    {0},
 };
 
 static const m_struct_t vf_opts = {