command: add sub-start & sub-end properties

These properties contain the current subtitle's start and end times.
Can be useful to cut sample audio through the scripting interface.

DOCS/man/input.rst

@@ -1916,6 +1916,17 @@ Property list
 
     This property is experimental and might be removed in the future.
 
+``sub-start``
+    Return the current subtitle start time (in seconds). If there's multiple
+    current subtitles, returns the first start time. If no current subtitle is
+    present null is returned instead.
+
+``sub-end``
+    Return the current subtitle start time (in seconds). If there's multiple
+    current subtitles, return the last end time. If no current subtitle is
+    present, or if it's present but has unknown or incorrect duration, null
+    is returned instead.
+
 ``playlist-pos`` (RW)
     Current position on playlist. The first entry is on position 0. Writing
     to the property will restart playback at the written entry.

player/command.c

@@ -2845,6 +2845,38 @@ static int mp_property_sub_text(void *ctx, struct m_property *prop,
     return m_property_strdup_ro(action, arg, text);
 }
 
+static struct sd_times get_times(void *ctx, struct m_property *prop,
+                                int action, void *arg)
+{
+    struct sd_times res = { .start = MP_NOPTS_VALUE, .end = MP_NOPTS_VALUE };
+    MPContext *mpctx = ctx;
+    struct track *track = mpctx->current_track[0][STREAM_SUB];
+    struct dec_sub *sub = track ? track->d_sub : NULL;
+    double pts = mpctx->playback_pts;
+    if (!sub || pts == MP_NOPTS_VALUE)
+        return res;
+    return sub_get_times(sub, pts);
+}
+
+static int mp_property_sub_start(void *ctx, struct m_property *prop,
+                                int action, void *arg)
+{
+    double start = get_times(ctx, prop, action, arg).start;
+    if (start == MP_NOPTS_VALUE)
+        return M_PROPERTY_UNAVAILABLE;
+    return m_property_double_ro(action, arg, start);
+}
+
+
+static int mp_property_sub_end(void *ctx, struct m_property *prop,
+                                int action, void *arg)
+{
+    double end = get_times(ctx, prop, action, arg).end;
+    if (end == MP_NOPTS_VALUE)
+        return M_PROPERTY_UNAVAILABLE;
+    return m_property_double_ro(action, arg, end);
+}
+
 static int mp_property_cursor_autohide(void *ctx, struct m_property *prop,
                                        int action, void *arg)
 {
@@ -3548,6 +3580,8 @@ static const struct m_property mp_properties_base[] = {
     {"sub-speed", mp_property_sub_speed},
     {"sub-pos", mp_property_sub_pos},
     {"sub-text", mp_property_sub_text},
+    {"sub-start", mp_property_sub_start},
+    {"sub-end", mp_property_sub_end},
 
     {"vf", mp_property_vf},
     {"af", mp_property_af},

sub/dec_sub.c

@@ -372,6 +372,23 @@ char *sub_get_text(struct dec_sub *sub, double pts)
     return text;
 }
 
+struct sd_times sub_get_times(struct dec_sub *sub, double pts)
+{
+    pthread_mutex_lock(&sub->lock);
+    struct sd_times res = { .start = MP_NOPTS_VALUE, .end = MP_NOPTS_VALUE };
+
+    pts = pts_to_subtitle(sub, pts);
+
+    sub->last_vo_pts = pts;
+    update_segment(sub);
+
+    if (sub->sd->driver->get_times)
+        res = sub->sd->driver->get_times(sub->sd, pts);
+
+    pthread_mutex_unlock(&sub->lock);
+    return res;
+}
+
 void sub_reset(struct dec_sub *sub)
 {
     pthread_mutex_lock(&sub->lock);

sub/dec_sub.h

@@ -21,6 +21,11 @@ enum sd_ctrl {
     SD_CTRL_SET_VIDEO_DEF_FPS,
 };
 
+struct sd_times {
+    double start;
+    double end;
+};
+
 struct attachment_list {
     struct demux_attachment *entries;
     int num_entries;
@@ -38,6 +43,7 @@ bool sub_read_packets(struct dec_sub *sub, double video_pts);
 void sub_get_bitmaps(struct dec_sub *sub, struct mp_osd_res dim, int format,
                      double pts, struct sub_bitmaps *res);
 char *sub_get_text(struct dec_sub *sub, double pts);
+struct sd_times sub_get_times(struct dec_sub *sub, double pts);
 void sub_reset(struct dec_sub *sub);
 void sub_select(struct dec_sub *sub, bool selected);
 void sub_update_opts(struct dec_sub *sub);

sub/sd.h

@@ -40,6 +40,7 @@ struct sd_functions {
     void (*get_bitmaps)(struct sd *sd, struct mp_osd_res dim, int format,
                         double pts, struct sub_bitmaps *res);
     char *(*get_text)(struct sd *sd, double pts);
+    struct sd_times (*get_times)(struct sd *sd, double pts);
 };
 
 struct lavc_conv;

sub/sd_ass.c

@@ -593,6 +593,35 @@ static char *get_text(struct sd *sd, double pts)
     return ctx->last_text;
 }
 
+static struct sd_times get_times(struct sd *sd, double pts)
+{
+    struct sd_ass_priv *ctx = sd->priv;
+    ASS_Track *track = ctx->ass_track;
+    struct sd_times res = { .start = MP_NOPTS_VALUE, .end = MP_NOPTS_VALUE };
+
+    if (pts == MP_NOPTS_VALUE || ctx->duration_unknown)
+        return res;
+
+    long long ipts = find_timestamp(sd, pts);
+
+    for (int i = 0; i < track->n_events; ++i) {
+        ASS_Event *event = track->events + i;
+        if (ipts >= event->Start && ipts < event->Start + event->Duration) {
+            double start = event->Start / 1000.0;
+            double end = event->Duration == UNKNOWN_DURATION ?
+                MP_NOPTS_VALUE : (event->Start + event->Duration) / 1000.0;
+
+            if (res.start == MP_NOPTS_VALUE || res.start > start)
+                res.start = start;
+
+            if (res.end == MP_NOPTS_VALUE || res.end < end)
+                res.end = end;
+        }
+    }
+
+    return res;
+}
+
 static void fill_plaintext(struct sd *sd, double pts)
 {
     struct sd_ass_priv *ctx = sd->priv;
@@ -687,6 +716,7 @@ const struct sd_functions sd_ass = {
     .decode = decode,
     .get_bitmaps = get_bitmaps,
     .get_text = get_text,
+    .get_times = get_times,
     .control = control,
     .reset = reset,
     .select = enable_output,

sub/sd_lavc.c

@@ -383,14 +383,8 @@ static void decode(struct sd *sd, struct demux_packet *packet)
     }
 }
 
-static void get_bitmaps(struct sd *sd, struct mp_osd_res d, int format,
-                        double pts, struct sub_bitmaps *res)
+static struct sub *get_current(struct sd_lavc_priv *priv, double pts)
 {
-    struct sd_lavc_priv *priv = sd->priv;
-    struct mp_subtitle_opts *opts = sd->opts;
-
-    priv->current_pts = pts;
-
     struct sub *current = NULL;
     for (int n = 0; n < MAX_QUEUE; n++) {
         struct sub *sub = &priv->subs[n];
@@ -407,6 +401,19 @@ static void get_bitmaps(struct sd *sd, struct mp_osd_res d, int format,
             break;
         }
     }
+    return current;
+}
+
+static void get_bitmaps(struct sd *sd, struct mp_osd_res d, int format,
+                        double pts, struct sub_bitmaps *res)
+{
+    struct sd_lavc_priv *priv = sd->priv;
+    struct mp_subtitle_opts *opts = sd->opts;
+
+    priv->current_pts = pts;
+
+    struct sub *current = get_current(priv, pts);
+
     if (!current)
         return;
 
@@ -483,6 +490,25 @@ static void get_bitmaps(struct sd *sd, struct mp_osd_res d, int format,
 
 }
 
+static struct sd_times get_times(struct sd *sd, double pts)
+{
+    struct sd_lavc_priv *priv = sd->priv;
+    struct sd_times res = { .start = MP_NOPTS_VALUE, .end = MP_NOPTS_VALUE };
+
+    if (pts == MP_NOPTS_VALUE)
+        return res;
+
+    struct sub *current = get_current(priv, pts);
+
+    if (!current)
+        return res;
+
+    res.start = current->pts;
+    res.end = current->endpts;
+
+    return res;
+}
+
 static bool accepts_packet(struct sd *sd, double min_pts)
 {
     struct sd_lavc_priv *priv = sd->priv;
@@ -622,6 +648,7 @@ const struct sd_functions sd_lavc = {
     .init = init,
     .decode = decode,
     .get_bitmaps = get_bitmaps,
+    .get_times = get_times,
     .accepts_packet = accepts_packet,
     .control = control,
     .reset = reset,

test/subtimes.js

@@ -0,0 +1,7 @@
+function subtimes() {
+  mp.msg.info("sub-start: " + mp.get_property_number("sub-start"));
+  mp.msg.info("sub-end: " + mp.get_property_number("sub-end"));
+  mp.msg.info("sub-text: " + mp.get_property_native("sub-text"));
+}
+
+mp.add_key_binding("t", "subtimes", subtimes);