sws_utils, zimg: destroy vo_x11 and vo_drm performance

Raise swscale and zimg default parameters. This restores screenshot
quality settings (maybe) unset in the commit before. Also expose some
more libswscale and zimg options.

Since these options are also used for VOs like x11 and drm, this will
make x11/drm/etc. much slower. For compensation, provide a profile that
sets the old option values: sw-fast. I'm also enabling zimg here, just
as an experiment.

The core problem is that we have a single set of command line options
which control the settings used for most swscale/zimg uses. This was
done in the previous commit. It cannot differentiate between the VOs,
which need to be realtime and may accept/require lower quality options,
and things like screenshots or vo_image, which can be slower, but should
not sacrifice quality by default.

Should this have two sets of options or something similar to do the
right thing depending on the code which calls libswscale? Maybe. Or
should I just ignore the problem, make it someone else's problem (users
who want to use software conversion VOs), provide a sub-optimal
solution, and call it a day? Definitely, sounds good, pushing to master,
goodbye.

5 files changed, 72 insertions, 41 deletions

diff --git a/video/filter/vf_fingerprint.c b/video/filter/vf_fingerprint.c
index 79273622b7..471d995f4f 100644
--- a/video/filter/vf_fingerprint.c
+++ b/video/filter/vf_fingerprint.c
@@ -15,6 +15,8 @@
  * License along with mpv.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <math.h>
+
 #include "common/common.h"
 #include "common/tags.h"
 #include "filters/filter.h"
@@ -204,6 +206,14 @@ static struct mp_filter *f_create(struct mp_filter *parent, void *options)
     MP_HANDLE_OOM(p->sws);
     p->zimg = mp_zimg_alloc();
     talloc_steal(p, p->zimg);
+    p->zimg->opts = (struct zimg_opts){
+        .scaler = ZIMG_RESIZE_BILINEAR,
+        .scaler_params = {NAN, NAN},
+        .scaler_chroma_params = {NAN, NAN},
+        .scaler_chroma = ZIMG_RESIZE_BILINEAR,
+        .dither = ZIMG_DITHER_NONE,
+        .fast = 1,
+    };
     return f;
 }
 
diff --git a/video/sws_utils.c b/video/sws_utils.c
index a41d4c6e76..47af77ca50 100644
--- a/video/sws_utils.c
+++ b/video/sws_utils.c
@@ -49,6 +49,8 @@ struct sws_opts {
     int chr_hshift;
     float chr_sharpen;
     float lum_sharpen;
+    int fast;
+    int bitexact;
     int zimg;
 };
 
@@ -73,19 +75,20 @@ const struct m_sub_options sws_conf = {
         OPT_INT("chs", chr_hshift, 0),
         OPT_FLOATRANGE("ls", lum_sharpen, 0, -100.0, 100.0),
         OPT_FLOATRANGE("cs", chr_sharpen, 0, -100.0, 100.0),
+        OPT_FLAG("fast", fast, 0),
+        OPT_FLAG("bitexact", bitexact, 0),
         OPT_FLAG("allow-zimg", zimg, 0),
         {0}
     },
     .size = sizeof(struct sws_opts),
     .defaults = &(const struct sws_opts){
-        .scaler = SWS_BICUBIC,
+        .scaler = SWS_LANCZOS,
     },
 };
 
 // Highest quality, but also slowest.
-const int mp_sws_hq_flags = SWS_LANCZOS | SWS_FULL_CHR_H_INT |
-                            SWS_FULL_CHR_H_INP | SWS_ACCURATE_RND |
-                            SWS_BITEXACT;
+static const int mp_sws_hq_flags = SWS_FULL_CHR_H_INT | SWS_FULL_CHR_H_INP |
+                                   SWS_ACCURATE_RND;
 
 // Fast, lossy.
 const int mp_sws_fast_flags = SWS_BILINEAR;
@@ -104,6 +107,10 @@ static void mp_sws_update_from_cmdline(struct mp_sws_context *ctx)
 
     ctx->flags = SWS_PRINT_INFO;
     ctx->flags |= opts->scaler;
+    if (!opts->fast)
+        ctx->flags |= mp_sws_hq_flags;
+    if (opts->bitexact)
+        ctx->flags |= SWS_BITEXACT;
 
     ctx->allow_zimg = opts->zimg;
 }
@@ -357,7 +364,7 @@ int mp_image_sw_blur_scale(struct mp_image *dst, struct mp_image *src,
                            float gblur)
 {
     struct mp_sws_context *ctx = mp_sws_alloc(NULL);
-    ctx->flags = mp_sws_hq_flags;
+    ctx->flags = SWS_LANCZOS | mp_sws_hq_flags;
     ctx->src_filter = sws_getDefaultFilter(gblur, gblur, 0, 0, 0, 0, 0);
     ctx->force_reload = true;
     int res = mp_sws_scale(ctx, dst, src);
diff --git a/video/sws_utils.h b/video/sws_utils.h
index de6a023524..ddf628cf23 100644
--- a/video/sws_utils.h
+++ b/video/sws_utils.h
@@ -13,7 +13,6 @@ struct mpv_global;
 // Guaranteed to be a power of 2 and > 1.
 #define SWS_MIN_BYTE_ALIGN MP_IMAGE_BYTE_ALIGN
 
-extern const int mp_sws_hq_flags;
 extern const int mp_sws_fast_flags;
 
 bool mp_sws_supported_format(int imgfmt);
diff --git a/video/zimg.c b/video/zimg.c
index 7ea60531e1..b568a6bbec 100644
--- a/video/zimg.c
+++ b/video/zimg.c
@@ -27,27 +27,43 @@
 
 static_assert(MP_IMAGE_BYTE_ALIGN >= ZIMG_ALIGN, "");
 
-struct zimg_opts {
-    int scaler;
-    int fast;
+static const struct m_opt_choice_alternatives mp_zimg_scalers[] = {
+    {"point",           ZIMG_RESIZE_POINT},
+    {"bilinear",        ZIMG_RESIZE_BILINEAR},
+    {"bicubic",         ZIMG_RESIZE_BICUBIC},
+    {"spline16",        ZIMG_RESIZE_SPLINE16},
+    {"spline36",        ZIMG_RESIZE_SPLINE36},
+    {"lanczos",         ZIMG_RESIZE_LANCZOS},
+    {0}
 };
 
+#define OPT_PARAM(name, var, flags) \
+    OPT_DOUBLE(name, var, (flags) | M_OPT_DEFAULT_NAN)
+
 #define OPT_BASE_STRUCT struct zimg_opts
 const struct m_sub_options zimg_conf = {
     .opts = (struct m_option[]) {
-        OPT_CHOICE("scaler", scaler, 0,
-                   ({"point",           ZIMG_RESIZE_POINT},
-                    {"bilinear",        ZIMG_RESIZE_BILINEAR},
-                    {"bicubic",         ZIMG_RESIZE_BICUBIC},
-                    {"spline16",        ZIMG_RESIZE_SPLINE16},
-                    {"lanczos",         ZIMG_RESIZE_LANCZOS})),
+        OPT_CHOICE_C("scaler", scaler, 0, mp_zimg_scalers),
+        OPT_PARAM("scaler-param-a", scaler_params[0], 0),
+        OPT_PARAM("scaler-param-b", scaler_params[1], 0),
+        OPT_CHOICE_C("scaler-chroma", scaler_chroma, 0, mp_zimg_scalers),
+        OPT_PARAM("scaler-chroma-param-a", scaler_chroma_params[0], 0),
+        OPT_PARAM("scaler-chroma-param-b", scaler_chroma_params[1], 0),
+        OPT_CHOICE("dither", dither, 0,
+                   ({"no",              ZIMG_DITHER_NONE},
+                    {"ordered",         ZIMG_DITHER_ORDERED},
+                    {"random",          ZIMG_DITHER_RANDOM},
+                    {"error-diffusion", ZIMG_DITHER_ERROR_DIFFUSION})),
         OPT_FLAG("fast", fast, 0),
         {0}
     },
     .size = sizeof(struct zimg_opts),
     .defaults = &(const struct zimg_opts){
-        .scaler = ZIMG_RESIZE_BILINEAR,
-        .fast = 1,
+        .scaler = ZIMG_RESIZE_LANCZOS,
+        .scaler_params = {NAN, NAN},
+        .scaler_chroma_params = {NAN, NAN},
+        .scaler_chroma = ZIMG_RESIZE_BILINEAR,
+        .dither = ZIMG_DITHER_RANDOM,
     },
 };
 
@@ -90,9 +106,7 @@ static void mp_zimg_update_from_cmdline(struct mp_zimg_context *ctx)
     m_config_cache_update(ctx->opts_cache);
 
     struct zimg_opts *opts = ctx->opts_cache->opts;
-
-    ctx->scaler = opts->scaler;
-    ctx->fast = opts->fast;
+    ctx->opts = *opts;
 }
 
 static zimg_chroma_location_e mp_to_z_chroma(enum mp_chroma_location cl)
@@ -183,13 +197,8 @@ struct mp_zimg_context *mp_zimg_alloc(void)
     struct mp_zimg_context *ctx = talloc_ptrtype(NULL, ctx);
     *ctx = (struct mp_zimg_context) {
         .log = mp_null_log,
-        .scaler = ZIMG_RESIZE_BILINEAR,
-        .scaler_params = {NAN, NAN},
-        .scaler_chroma = ZIMG_RESIZE_BILINEAR,
-        .scaler_chroma_params = {NAN, NAN},
-        .dither = ZIMG_DITHER_NONE,
-        .fast = true,
     };
+    ctx->opts = *(struct zimg_opts *)zimg_conf.defaults;
     talloc_set_destructor(ctx, free_mp_zimg);
     return ctx;
 }
@@ -504,7 +513,7 @@ static bool setup_format(zimg_image_format *zfmt, struct mp_zimg_repack *r,
     zfmt->color_primaries = mp_to_z_prim(fmt.color.primaries);
     zfmt->chroma_location = mp_to_z_chroma(fmt.chroma_location);
 
-    if (ctx && ctx->fast) {
+    if (ctx && ctx->opts.fast) {
         // mpv's default for RGB output slows down zimg significantly.
         if (zfmt->transfer_characteristics == ZIMG_TRANSFER_IEC_61966_2_1 &&
             zfmt->color_family == ZIMG_COLOR_RGB)
@@ -547,6 +556,8 @@ static bool allocate_buffer(struct mp_zimg_context *ctx,
 
 bool mp_zimg_config(struct mp_zimg_context *ctx)
 {
+    struct zimg_opts *opts = &ctx->opts;
+
     destroy_zimg(ctx);
 
     if (ctx->opts_cache)
@@ -569,19 +580,19 @@ bool mp_zimg_config(struct mp_zimg_context *ctx)
     zimg_graph_builder_params params;
     zimg_graph_builder_params_default(&params, ZIMG_API_VERSION);
 
-    params.resample_filter = ctx->scaler;
-    params.filter_param_a = ctx->scaler_params[0];
-    params.filter_param_b = ctx->scaler_params[1];
+    params.resample_filter = opts->scaler;
+    params.filter_param_a = opts->scaler_params[0];
+    params.filter_param_b = opts->scaler_params[1];
 
-    params.resample_filter_uv = ctx->scaler_chroma;
-    params.filter_param_a_uv = ctx->scaler_chroma_params[0];
-    params.filter_param_b_uv = ctx->scaler_chroma_params[1];
+    params.resample_filter_uv = opts->scaler_chroma;
+    params.filter_param_a_uv = opts->scaler_chroma_params[0];
+    params.filter_param_b_uv = opts->scaler_chroma_params[1];
 
-    params.dither_type = ctx->dither;
+    params.dither_type = opts->dither;
 
     params.cpu_type = ZIMG_CPU_AUTO_64B;
 
-    if (ctx->fast)
+    if (opts->fast)
         params.allow_approximate_gamma = 1;
 
     if (ctx->src.color.sig_peak > 0)
diff --git a/video/zimg.h b/video/zimg.h
index 9fa247d061..0ef9c5a3a0 100644
--- a/video/zimg.h
+++ b/video/zimg.h
@@ -13,6 +13,15 @@ struct mpv_global;
 bool mp_zimg_supports_in_format(int imgfmt);
 bool mp_zimg_supports_out_format(int imgfmt);
 
+struct zimg_opts {
+    int scaler;
+    double scaler_params[2];
+    int scaler_chroma;
+    double scaler_chroma_params[2];
+    int dither;
+    int fast;
+};
+
 struct mp_zimg_context {
     // Can be set for verbose error printing.
     struct mp_log *log;
@@ -20,12 +29,7 @@ struct mp_zimg_context {
     // User configuration. Note: changing these requires calling mp_zimg_config()
     // to update the filter graph. The first mp_zimg_convert() call (or if the
     // image format changes) will do this automatically.
-    zimg_resample_filter_e scaler;
-    double scaler_params[2];
-    zimg_resample_filter_e scaler_chroma;
-    double scaler_chroma_params[2];
-    zimg_dither_type_e dither;
-    bool fast; // reduce quality for better performance
+    struct zimg_opts opts;
 
     // Input/output parameters. Note: if these mismatch with the
     // mp_zimg_convert() parameters, mp_zimg_config() will be called