core: runtime Matroska edition switching

Add a new slave property which switches the current Matroska edition.
Since each edition can define an entirely new timeline, switching the
edition will simply restart playback at the beginning of the file with
the new edition selected.

Add 'E' as new keybinding to step the edition property.

DVD titles are still separate. Apparently they work similarly, but I
don't have any multi-title DVDs for testing. Also, cdda (for audio CDs)
uses the same mechanism as DVDs to report a number of titles, so there
seems to be confusion what exactly this mechanism is supposed to do.
That's why the edition code is completely separate for now.

Remove demuxer.num_titles. It was just a rather useless cache for the
return value of the DVD titles related STREAM_CTRL.

One rather obscure corner case isn't taken care of: if the ordered
chapters file has file local options set, they are reset on playback
restart. This is unexpected, because edition switching is meant to
behave like seeking back to the beginning of the file.

1 files changed, 68 insertions, 4 deletions

diff --git a/command.c b/command.c
index 065802b6d0..f0b17719db 100644
--- a/command.c
+++ b/command.c
@@ -434,6 +434,51 @@ static int mp_property_chapter(m_option_t *prop, int action, void *arg,
     return M_PROPERTY_OK;
 }
 
+static int mp_property_edition(m_option_t *prop, int action, void *arg,
+                               MPContext *mpctx)
+{
+    struct MPOpts *opts = &mpctx->opts;
+    struct demuxer *demuxer = mpctx->master_demuxer;
+    if (!demuxer)
+        return M_PROPERTY_UNAVAILABLE;
+    if (demuxer->num_editions <= 0)
+        return M_PROPERTY_UNAVAILABLE;
+
+    int edition = demuxer->edition;
+
+    switch (action) {
+    case M_PROPERTY_GET:
+    case M_PROPERTY_PRINT:
+        return m_property_int_ro(prop, action, arg, edition);
+    case M_PROPERTY_SET:
+        if (!arg)
+            return M_PROPERTY_ERROR;
+        M_PROPERTY_CLAMP(prop, *(int *)arg);
+        edition = *(int *)arg;
+        break;
+    case M_PROPERTY_STEP_UP:
+    case M_PROPERTY_STEP_DOWN: {
+        edition += arg ? *(int *)arg : (action == M_PROPERTY_STEP_UP ? 1 : -1);
+        if (edition < 0)
+            edition = demuxer->num_editions - 1;
+        if (edition >= demuxer->num_editions)
+            edition = 0;
+        break;
+    }
+    default:
+        return M_PROPERTY_NOT_IMPLEMENTED;
+    }
+
+    if (edition != demuxer->edition) {
+        opts->edition_id = edition;
+        mpctx->stop_play = PT_RESTART;
+        set_osd_tmsg(mpctx, OSD_MSG_TEXT, 1, opts->osd_duration,
+                     "Playing edition %d of %d.", edition + 1,
+                     demuxer->num_editions);
+    }
+    return M_PROPERTY_OK;
+}
+
 /// Number of titles in file
 static int mp_property_titles(m_option_t *prop, int action, void *arg,
                               MPContext *mpctx)
@@ -441,10 +486,9 @@ static int mp_property_titles(m_option_t *prop, int action, void *arg,
     struct demuxer *demuxer = mpctx->master_demuxer;
     if (!demuxer)
         return M_PROPERTY_UNAVAILABLE;
-    if (demuxer->num_titles == 0)
-        stream_control(demuxer->stream, STREAM_CTRL_GET_NUM_TITLES,
-                       &demuxer->num_titles);
-    return m_property_int_ro(prop, action, arg, demuxer->num_titles);
+    int num_titles = 0;
+    stream_control(demuxer->stream, STREAM_CTRL_GET_NUM_TITLES, &num_titles);
+    return m_property_int_ro(prop, action, arg, num_titles);
 }
 
 /// Number of chapters in file
@@ -457,6 +501,17 @@ static int mp_property_chapters(m_option_t *prop, int action, void *arg,
     return m_property_int_ro(prop, action, arg, count);
 }
 
+static int mp_property_editions(m_option_t *prop, int action, void *arg,
+                                MPContext *mpctx)
+{
+    struct demuxer *demuxer = mpctx->master_demuxer;
+    if (!demuxer)
+        return M_PROPERTY_UNAVAILABLE;
+    if (demuxer->num_editions <= 0)
+        return M_PROPERTY_UNAVAILABLE;
+    return m_property_int_ro(prop, action, arg, demuxer->num_editions);
+}
+
 /// Current dvd angle (RW)
 static int mp_property_angle(m_option_t *prop, int action, void *arg,
                              MPContext *mpctx)
@@ -1638,10 +1693,13 @@ static const m_option_t mp_properties[] = {
       M_OPT_MIN, 0, 0, NULL },
     { "chapter", mp_property_chapter, CONF_TYPE_INT,
       M_OPT_MIN, 0, 0, NULL },
+    { "edition", mp_property_edition, CONF_TYPE_INT,
+      M_OPT_MIN, -1, 0, NULL },
     { "titles", mp_property_titles, CONF_TYPE_INT,
       0, 0, 0, NULL },
     { "chapters", mp_property_chapters, CONF_TYPE_INT,
       0, 0, 0, NULL },
+    { "editions", mp_property_editions, CONF_TYPE_INT },
     { "angle", mp_property_angle, CONF_TYPE_INT,
       CONF_RANGE, -2, 10, NULL },
     { "metadata", mp_property_metadata, CONF_TYPE_STRING_LIST,
@@ -2110,6 +2168,12 @@ static void show_tracks_on_osd(MPContext *mpctx)
         res = talloc_asprintf_append(res, "\n");
     }
 
+    struct demuxer *demuxer = mpctx->master_demuxer;
+    if (demuxer && demuxer->num_editions > 1)
+        res = talloc_asprintf_append(res, "\nEdition: %d of %d\n",
+                                     demuxer->edition + 1,
+                                     demuxer->num_editions);
+
     set_osd_msg(mpctx, OSD_MSG_TEXT, 1, opts->osd_duration, "%s", res);
     talloc_free(res);
 }