command: change the hwdec properties

Another very minor step towards property/option unification.

Not bothering with interface compatibility here.

DOCS/interface-changes.rst

@@ -20,6 +20,11 @@ Interface changes
 ::
 
  --- mpv 0.10.0 will be released ---
+    - completely change how the hwdec properties work:
+        - "hwdec" now reflects the --hwdec option
+        - "hwdec-detected" does partially what the old "hwdec" property did
+          (and also, "detected-hwdec" is removed)
+        - "hwdec-active" is added
     - add protocol-list property
     - deprecate audio-samplerate and audio-channels properties
       (audio-params sub-properties are the replacement)

DOCS/man/input.rst

@@ -1246,25 +1246,29 @@ Property list
     See ``--hue``.
 
 ``hwdec`` (RW)
-    Return the current hardware decoder that is used. This uses the same values
-    as the ``--hwdec`` option. If software decoding is active, this returns
-    ``no``. You can write this property. Then the ``--hwdec`` option is set to
-    the new value, and video decoding will be reinitialized (internally, the
-    player will perform a seek to refresh the video properly).
+    Reflects the ``--hwdec`` option.
 
-    Note that you don't know the success of the operation immediately after
-    writing this property. It happens with a delay as video is reinitialized.
+    Writing to it may change the currently used hardware decoder, if possible.
+    (Internally, the player may reinitialize the decoder, and will perform a
+    seek to refresh the video properly.) You can watch the other hwdec
+    properties to see whether this was successful.
 
-``detected-hwdec``
-    Return the current hardware decoder that was detected and opened. Returns
-    the same values as ``hwdec``.
+    Unlike in mpv 0.9.x and before, this does not return the currently active
+    hardware decoder.
 
-    This is known only once the VO has opened (and possibly later). With some
-    VOs (like ``opengl``), this is never known in advance, but only when the
-    decoder attempted to create the hw decoder successfully. Also, hw decoders
-    with ``-copy`` suffix are returned only while hw decoding is active (and
-    unset afterwards). All this reflects how detecting hw decoders are
-    detected and used internally in mpv.
+``hwdec-active``
+    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.
+    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
+    advance, but only when the decoder attempted to create the hw decoder
+    successfully. Also, hw decoders with ``-copy`` suffix will return ``no``
+    while no video is being decoded. All this reflects how detecting hw decoders
+    are detected and used internally in mpv.
 
 ``panscan`` (RW)
     See ``--panscan``.

player/command.c

@@ -2010,41 +2010,51 @@ static int mp_property_hwdec(void *ctx, struct m_property *prop,
     MPContext *mpctx = ctx;
     struct MPOpts *opts = mpctx->opts;
     struct dec_video *vd = mpctx->d_video;
-    if (!vd)
-        return M_PROPERTY_UNAVAILABLE;
 
-    int current = 0;
-    video_vd_control(vd, VDCTRL_GET_HWDEC, &current);
-
-    switch (action) {
-    case M_PROPERTY_GET:
-        *(int *)arg = current;
-        return M_PROPERTY_OK;
-    case M_PROPERTY_SET: {
+    if (action == M_PROPERTY_SET) {
         int new = *(int *)arg;
-        if (current == new)
+
+        if (opts->hwdec_api == new)
             return M_PROPERTY_OK;
-        if (!mpctx->d_video)
-            return M_PROPERTY_ERROR;
-        double last_pts = mpctx->last_vo_pts;
-        uninit_video_chain(mpctx);
+
         opts->hwdec_api = new;
-        reinit_video_chain(mpctx);
-        if (last_pts != MP_NOPTS_VALUE)
-            queue_seek(mpctx, MPSEEK_ABSOLUTE, last_pts, MPSEEK_EXACT, true);
+
+        if (!vd)
+            return M_PROPERTY_OK;
+
+        int current = -2;
+        video_vd_control(vd, VDCTRL_GET_HWDEC, &current);
+        if (current != opts->hwdec_api) {
+            double last_pts = mpctx->last_vo_pts;
+            uninit_video_chain(mpctx);
+            reinit_video_chain(mpctx);
+            if (last_pts != MP_NOPTS_VALUE)
+                queue_seek(mpctx, MPSEEK_ABSOLUTE, last_pts, MPSEEK_EXACT, true);
+        }
         return M_PROPERTY_OK;
     }
-    }
     return mp_property_generic_option(mpctx, prop, action, arg);
 }
 
+static int mp_property_hwdec_active(void *ctx, struct m_property *prop,
+                                    int action, void *arg)
+{
+    MPContext *mpctx = ctx;
+    struct dec_video *vd = mpctx->d_video;
+    bool active = false;
+    if (vd) {
+        int current = 0;
+        video_vd_control(vd, VDCTRL_GET_HWDEC, &current);
+        active = current > 0;
+    }
+    return m_property_flag_ro(action, arg, active);
+}
+
 static int mp_property_detected_hwdec(void *ctx, struct m_property *prop,
                                       int action, void *arg)
 {
     MPContext *mpctx = ctx;
     struct dec_video *vd = mpctx->d_video;
-    if (!vd || !vd->hwdec_info)
-        return M_PROPERTY_UNAVAILABLE;
 
     switch (action) {
     case M_PROPERTY_GET_TYPE: {
@@ -2053,14 +2063,16 @@ static int mp_property_detected_hwdec(void *ctx, struct m_property *prop,
         return mp_property_generic_option(mpctx, &dummy, action, arg);
     }
     case M_PROPERTY_GET: {
-        int d = vd->hwdec_info->hwctx ? vd->hwdec_info->hwctx->type : HWDEC_NONE;
-        if (d) {
-            *(int *)arg = d;
-        } else {
-            // Maybe one of the "-copy" ones. These are "detected" every time
-            // the decoder is opened, so we don't know much about them otherwise.
-            return mp_property_hwdec(ctx, prop, action, arg);
-        }
+        int current = 0;
+        if (vd)
+            video_vd_control(vd, VDCTRL_GET_HWDEC, &current);
+
+        if (current <= 0 && vd && vd->hwdec_info && vd->hwdec_info->hwctx)
+            current = vd->hwdec_info->hwctx->type;
+
+        // In case of the "-copy" ones, which are "detected" every time the
+        // decoder is opened, return "no" if no decoding is active.
+        *(int *)arg = current > 0 ? current : 0;
         return M_PROPERTY_OK;
     }
     }
@@ -3397,7 +3409,8 @@ static const struct m_property mp_properties[] = {
     {"vid", mp_property_video},
     {"program", mp_property_program},
     {"hwdec", mp_property_hwdec},
-    {"detected-hwdec", mp_property_detected_hwdec},
+    {"hwdec-active", mp_property_hwdec_active},
+    {"hwdec-detected", mp_property_detected_hwdec},
 
     {"estimated-frame-count", mp_property_frame_count},
     {"estimated-frame-number", mp_property_frame_number},