command: change some hwdec properties

Introduce hwdec-current and hwdec-interop properties.

Deprecate hwdec-detected, which never made a lot of sense, and which is
replaced by the new properties. hwdec-active also becomes useless, as
hwdec-current is a superset, so it's deprecated too (for now).

DOCS/interface-changes.rst

@@ -25,6 +25,9 @@ Interface changes
       point is unsert, and the end of the file for an unset B loop point
     - deprecate --sub-ass=no option by --ass-style-override=strip
       (also needs --embeddedfonts=no)
+    - add "hwdec-interop" and "hwdec-current" properties
+    - deprecated "hwdec-active" and "hwdec-detected" properties (to be removed
+      in mpv 0.19.0)
  --- mpv 0.17.0 ---
     - deprecate "track-list/N/audio-channels" property (use
       "track-list/N/demux-channel-count" instead)

DOCS/man/input.rst

@@ -1385,14 +1385,39 @@ Property list
     properties to see whether this was successful.
 
     Unlike in mpv 0.9.x and before, this does not return the currently active
-    hardware decoder.
+    hardware decoder. Since mpv 0.17.1, ``hwdec-current`` is available for
+    this purpose.
+
+``hwdec-current``
+    Return the current hardware decoding in use. If decoding is active, return
+    one of the values used by the ``hwdec`` option/property. ``no`` indicates
+    software decoding. If no decoder is loaded, the property is unavailable.
+
+``hwdec-interop``
+    This returns the currently loaded hardware decoding/output interop driver.
+    This is known only once the VO has opened (and possibly later). With some
+    VOs (like ``opengl``), this might be never known in advance, but only when
+    the decoder attempted to create the hw decoder successfully. (Using
+    ``--hwdec-preload`` can load it eagerly.) If there are multiple drivers
+    loaded, they will be separated by ``,``.
+
+    If no VO is active or no interop driver is known, this property is
+    unavailable.
+
+    This does not necessarily use the same values as ``hwdec``. There can be
+    multiple interop drivers for the same hardware decoder, depending on
+    platform and VO.
 
 ``hwdec-active``
+    Deprecated. To be removed in mpv 0.19.0. Use ``hwdec-current`` instead.
+
     Return ``yes`` or ``no``, depending on whether any type of hardware decoding
     is actually in use.
 
 ``hwdec-detected``
-    If software decoding is active, this returns the hardware decoder in use.
+    Deprecated. To be removed in mpv 0.19.0.
+
+    If hardware decoding is active, this returns the hardware decoder in use.
     Otherwise, it returns either ``no``, or if applicable, the currently loaded
     hardware decoding API. This is known only once the VO has opened (and
     possibly later). With some VOs (like ``opengl``), this is never known in

player/command.c

@@ -2166,6 +2166,51 @@ static int mp_property_hwdec(void *ctx, struct m_property *prop,
     return mp_property_generic_option(mpctx, prop, action, arg);
 }
 
+static int mp_property_hwdec_current(void *ctx, struct m_property *prop,
+                                     int action, void *arg)
+{
+    MPContext *mpctx = ctx;
+    struct track *track = mpctx->current_track[0][STREAM_VIDEO];
+    struct dec_video *vd = track ? track->d_video : NULL;
+
+    if (!vd)
+        return M_PROPERTY_UNAVAILABLE;
+
+    switch (action) {
+    case M_PROPERTY_GET_TYPE: {
+        // Abuse another hwdec option to resolve the value names
+        struct m_property dummy = {.name = "hwdec"};
+        return mp_property_generic_option(mpctx, &dummy, action, arg);
+    }
+    case M_PROPERTY_GET: {
+        int current = HWDEC_NONE;
+        video_vd_control(vd, VDCTRL_GET_HWDEC, &current);
+        if (current == HWDEC_AUTO)
+            current = HWDEC_NONE;
+        *(int *)arg = current;
+        return M_PROPERTY_OK;
+    }
+    }
+    return M_PROPERTY_NOT_IMPLEMENTED;
+}
+
+static int mp_property_hwdec_interop(void *ctx, struct m_property *prop,
+                                     int action, void *arg)
+{
+    MPContext *mpctx = ctx;
+    if (!mpctx->video_out)
+        return M_PROPERTY_UNAVAILABLE;
+
+    struct mp_hwdec_info *hwdec_info = NULL;
+    vo_control(mpctx->video_out, VOCTRL_GET_HWDEC_INFO, &hwdec_info);
+    struct mp_hwdec_ctx *hwctx = hwdec_info ? hwdec_info->hwctx : NULL;
+    const char *name = hwctx ? hwctx->driver_name : NULL;
+    if (!name && hwctx && hwctx->type != HWDEC_NONE && hwctx->type != HWDEC_AUTO)
+        name = m_opt_choice_str(mp_hwdec_names, hwctx->type);
+
+    return m_property_strdup_ro(action, arg, name);
+}
+
 static int mp_property_hwdec_active(void *ctx, struct m_property *prop,
                                     int action, void *arg)
 {
@@ -3696,6 +3741,8 @@ static const struct m_property mp_properties[] = {
     {"program", mp_property_program},
     {"hwdec", mp_property_hwdec},
     {"hwdec-active", mp_property_hwdec_active},
+    {"hwdec-current", mp_property_hwdec_current},
+    {"hwdec-interop", mp_property_hwdec_interop},
     {"hwdec-detected", mp_property_detected_hwdec},
 
     {"estimated-frame-count", mp_property_frame_count},

video/hwdec.h

@@ -26,6 +26,7 @@ extern const struct m_opt_choice_alternatives mp_hwdec_names[];
 
 struct mp_hwdec_ctx {
     enum hwdec_type type;
+    const char *driver_name; // NULL if unknown/not loaded
 
     void *priv; // for free use by hwdec implementation
 

video/out/opengl/hwdec.c

@@ -79,6 +79,8 @@ static struct gl_hwdec *load_hwdec_driver(struct mp_log *log, GL *gl,
         mp_verbose(log, "Loading failed.\n");
         return NULL;
     }
+    if (hwdec->hwctx && !hwdec->hwctx->driver_name)
+        hwdec->hwctx->driver_name = hwdec->driver->name;
     return hwdec;
 }
 

video/out/opengl/hwdec.h

@@ -27,7 +27,7 @@ struct gl_hwdec {
 };
 
 struct gl_hwdec_driver {
-    // Name of the interop backend. This is used for logging only.
+    // Name of the interop backend. This is used for informational purposes only.
     const char *name;
     // Used to explicitly request a specific API.
     enum hwdec_type api;