core: add --keep-open, which doesn't close the file on EOF

The --keep-open option causes mpv not to close the current file.
Instead, it will pause, and allow the user to seek around. When
seeking beyond the end of the file, mpv does a precise seek back to
the previous last known position that produced video output.

In some corner cases, mpv might not be able to produce video output at
all, despite having created a VO. (Possibly when only 1 frame could be
decoded, but the video filter chain queues frames. Then a VO would be
created, without sending an actual video frame to the VO.) In these
cases, the VO window will not redraw, not even OSD.

Based on a patch by coax [1].

[1] http://devel.mplayer2.org/ticket/210#comment:4

1 files changed, 14 insertions, 0 deletions

diff --git a/core/mplayer.c b/core/mplayer.c
index 39d5c37543..1946fd6e60 100644
--- a/core/mplayer.c
+++ b/core/mplayer.c
@@ -3183,6 +3183,7 @@ static void run_playloop(struct MPContext *mpctx)
         vo_new_frame_imminent(vo);
         struct sh_video *sh_video = mpctx->sh_video;
         mpctx->video_pts = sh_video->pts;
+        mpctx->last_vo_pts = mpctx->video_pts;
         update_subtitles(mpctx, sh_video->pts);
         update_osd_msg(mpctx);
         draw_osd(mpctx);
@@ -3369,6 +3370,18 @@ static void run_playloop(struct MPContext *mpctx)
         queue_seek(mpctx, MPSEEK_RELATIVE, step_sec, 0);
     }
 
+    if (opts->keep_open && mpctx->stop_play == AT_END_OF_FILE) {
+        mpctx->stop_play = KEEP_PLAYING;
+        pause_player(mpctx);
+        if (mpctx->video_out && !mpctx->video_out->hasframe) {
+            // Force screen refresh to make OSD usable
+            double seek_to = mpctx->last_vo_pts;
+            if (seek_to == MP_NOPTS_VALUE)
+                seek_to = 0; // arbitrary default
+            queue_seek(mpctx, MPSEEK_ABSOLUTE, seek_to, 1);
+        }
+    }
+
     /* Looping. */
     if (opts->loop_times >= 0 && (mpctx->stop_play == AT_END_OF_FILE ||
                                   mpctx->stop_play == PT_NEXT_ENTRY)) {
@@ -4019,6 +4032,7 @@ goto_enable_cache:
     mpctx->drop_message_shown = 0;
     mpctx->restart_playback = true;
     mpctx->video_pts = 0;
+    mpctx->last_vo_pts = MP_NOPTS_VALUE;
     mpctx->last_seek_pts = 0;
     mpctx->hrseek_active = false;
     mpctx->hrseek_framedrop = false;