video: add a "hwdec" property to enable or disable hw decoding at runtime

DOCS/man/en/input.rst

@@ -879,6 +879,16 @@ Property list
 ``hue`` (RW)
     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).
+
+    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.
+
 ``panscan`` (RW)
     See ``--panscan``.
 

player/command.c

@@ -1473,6 +1473,38 @@ static int mp_property_program(m_option_t *prop, int action, void *arg,
     return M_PROPERTY_NOT_IMPLEMENTED;
 }
 
+static int mp_property_hwdec(m_option_t *prop, int action, void *arg,
+                             MPContext *mpctx)
+{
+    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: {
+        int new = *(int *)arg;
+        if (current == new)
+            return M_PROPERTY_OK;
+        if (!(mpctx->initialized_flags & INITIALIZED_VCODEC))
+            return M_PROPERTY_ERROR;
+        double last_pts = mpctx->last_vo_pts;
+        uninit_player(mpctx, INITIALIZED_VCODEC);
+        opts->hwdec_api = new;
+        reinit_video_chain(mpctx);
+        if (last_pts != MP_NOPTS_VALUE)
+            queue_seek(mpctx, MPSEEK_ABSOLUTE, last_pts, 1, true);
+        return M_PROPERTY_OK;
+    }
+    }
+    return mp_property_generic_option(prop, action, arg, mpctx);
+}
 
 /// Fullscreen state (RW)
 static int mp_property_fullscreen(m_option_t *prop,
@@ -2348,6 +2380,7 @@ static const m_option_t mp_properties[] = {
     M_OPTION_PROPERTY_CUSTOM("vid", mp_property_video),
     { "program", mp_property_program, CONF_TYPE_INT,
       CONF_RANGE, -1, 65535, NULL },
+    M_OPTION_PROPERTY_CUSTOM("hwdec", mp_property_hwdec),
 
     { "osd-width", mp_property_osd_w, CONF_TYPE_INT },
     { "osd-height", mp_property_osd_h, CONF_TYPE_INT },

video/decode/lavc.h

@@ -26,6 +26,7 @@ typedef struct lavc_ctx {
     AVCodecContext *avctx;
     AVFrame *pic;
     struct vd_lavc_hwdec *hwdec;
+    int selected_hwdec;
     enum AVPixelFormat pix_fmt;
     int best_csp;
     enum AVDiscard skip_frame;

video/decode/vd.h

@@ -45,6 +45,7 @@ enum vd_ctrl {
     VDCTRL_RESET = 1, // reset decode state after seeking
     VDCTRL_QUERY_UNSEEN_FRAMES, // current decoder lag
     VDCTRL_FORCE_HWDEC_FALLBACK, // force software decoding fallback
+    VDCTRL_GET_HWDEC,
 };
 
 #endif /* MPLAYER_VD_H */

video/decode/vd_lavc.c

@@ -225,6 +225,8 @@ static int init(struct dec_video *vd, const char *decoder)
     ctx->log = vd->log;
     ctx->opts = vd->opts;
 
+    ctx->selected_hwdec = vd->opts->hwdec_api;
+
     if (bstr_endswith0(bstr0(decoder), "_vdpau")) {
         MP_WARN(vd, "VDPAU decoder '%s' was requested. "
                 "This way of enabling hardware\ndecoding is not supported "
@@ -646,6 +648,13 @@ static int control(struct dec_video *vd, int cmd, void *arg)
             delay += avctx->thread_count - 1;
         *(int *)arg = delay;
         return CONTROL_TRUE;
+    case VDCTRL_GET_HWDEC: {
+        int hwdec = ctx->selected_hwdec;
+        if (!ctx->software_fallback_decoder)
+            hwdec = 0;
+        *(int *)arg = hwdec;
+        return CONTROL_TRUE;
+    }
     case VDCTRL_FORCE_HWDEC_FALLBACK:
         return force_fallback(vd);
     }