demux: make determining seek capability generic

Instead of having each demuxer do it (only demux_mkv actually did...),
let generic code determine whether the file is seekable. This requires
adding exceptions to demuxers where the stream is not seekable, but the
demuxer is.

Sort-of try to improve handling of unseekable files in the player. Exit
early if the file is determined to be unseekable, instead of resetting
all decoders and then performing a pointless seek.

Add an exception to allow seeking if the file is not seekable, but the
stream cache is enabled. Print a warning in this case, because seeking
outside the cache (which we can't prevent since the demuxer is not aware
of this problem) still messes everything up.

1 files changed, 2 insertions, 0 deletions

diff --git a/demux/demux_subreader.c b/demux/demux_subreader.c
index cc02e61595..21bcf21614 100644
--- a/demux/demux_subreader.c
+++ b/demux/demux_subreader.c
@@ -1358,6 +1358,8 @@ static int d_open_file(struct demuxer *demuxer, enum demux_check check)
     add_sub_data(demuxer, sd);
     subdata_free(sd);
 
+    demuxer->seekable = true;
+
     return 0;
 }