demux_timeline: disable pointless packet cache for sub-demuxers

It seems like there's nothing stopping from sub-demuxers from keeping
packets in the cache, even if it's completely pointless. The top-most
demuxer (demux_timeline) already takes care of caching, so sub-demuxers
only waste space and time with this.

Add a function that can disable the packet cache even at runtime and
after packets are read. (It's not clear whether it really can happen
that packets are read before demux_timeline gets the sub-demuxers, but
there's no reason to make it too fragile.) Call it on all sub-demuxers.

For this to work, it seems we have to move the code for setting the
seekable_cache flag to before demux_timeline is potentially initialized,
because otherwise the cache would be reenabled if the demuxer triggering
timeline support is a timeline segment itself (e.g. ordered chapters).

1 files changed, 7 insertions, 0 deletions

diff --git a/demux/demux_timeline.c b/demux/demux_timeline.c
index 288e9f750a..4b9b3124fa 100644
--- a/demux/demux_timeline.c
+++ b/demux/demux_timeline.c
@@ -170,6 +170,8 @@ static void reopen_lazy_segments(struct demuxer *demuxer)
                                    demuxer->stream->cancel, demuxer->global);
     if (!p->current->d && !demux_cancel_test(demuxer))
         MP_ERR(demuxer, "failed to load segment\n");
+    if (p->current->d)
+        demux_disable_cache(p->current->d);
     associate_streams(demuxer, p->current);
 }
 
@@ -385,6 +387,11 @@ static int d_open(struct demuxer *demuxer, enum demux_check check)
         struct timeline_part *part = &p->tl->parts[n];
         struct timeline_part *next = &p->tl->parts[n + 1];
 
+        // demux_timeline already does caching, doing it for the sub-demuxers
+        // would be pointless and wasteful.
+        if (part->source)
+            demux_disable_cache(part->source);
+
         struct segment *seg = talloc_ptrtype(p, seg);
         *seg = (struct segment){
             .d = part->source,