demux: deprecate --cache-secs

Because it's confusing and useless. If nobody complains, we'll have one
weird cache configuration option less.

1 files changed, 13 insertions, 2 deletions

diff --git a/DOCS/man/options.rst b/DOCS/man/options.rst
index 110fe7420d..09e06aa674 100644
--- a/DOCS/man/options.rst
+++ b/DOCS/man/options.rst
@@ -3578,8 +3578,13 @@ Demuxer
     a timestamp difference higher than the readahead amount relative to the
     last packet returned to the decoder, the demuxer keeps reading.
 
-    Note that the ``--cache-secs`` option will override this value if a cache
-    is enabled, and the value is larger.
+    Note that enabling the cache (such as ``--cache=yes``, or if the input
+    is considered a network stream, and ``--cache=auto`` is used), this option
+    is mostly ignored. (``--cache-secs`` will override this. Technically, the
+    maximum of both options is used.)
+
+    The main purpose of this option is to limit the readhead for local playback,
+    since a large readahead value is not overly useful in this case.
 
     (This value tends to be fuzzy, because many file formats don't store linear
     timestamps.)
@@ -4393,6 +4398,12 @@ Cache
     Turn off input stream caching. See ``--cache``.
 
 ``--cache-secs=<seconds>``
+    Deprecated. Once this option is removed, there will be no way to limit the
+    cache size by time (only by size with ``--demuxer-max-bytes``). This option
+    is considered useless, since there is no good reason to limit the cache by
+    time, and the default value of this ption is already something very high.
+    The interactions with the other cache options is also confusing.
+
     How many seconds of audio/video to prefetch if the cache is active. This
     overrides the ``--demuxer-readahead-secs`` option if and only if the cache
     is enabled and the value is larger. The default value is set to something