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authorwm4 <wm4@nowhere>2020-06-23 20:46:52 +0200
committerwm4 <wm4@nowhere>2020-06-23 20:47:22 +0200
commit1194ecd154526fae3641bc6d10ea83d2d1d0f404 (patch)
tree226a72c88850375a5f41a5a9b474787b510d2bf2
parent0e2d4ee595987d27b1b19cd12e6ebd6ccc660034 (diff)
downloadmpv-1194ecd154526fae3641bc6d10ea83d2d1d0f404.tar.bz2
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manpage: --demuxer-seekable-cache is useless
De-emphasize it, since a user should usually not use it. This _could_ be used to make the cache seekable with --cache=no, but it's better and more intuitive to use --cache=yes. As such, the only use of this is for debugging. I'm not quite sure if this should be removed entirely, but I still see some value in it (for example if you want the cache lookahead, but you're using a stream where cache seeking is somehow broken).
-rw-r--r--DOCS/man/options.rst37
1 files changed, 18 insertions, 19 deletions
diff --git a/DOCS/man/options.rst b/DOCS/man/options.rst
index e5e43bfb7f..2f49e629c1 100644
--- a/DOCS/man/options.rst
+++ b/DOCS/man/options.rst
@@ -570,14 +570,13 @@ Playback Control
logged errors).
- The demuxer cache is essential for backward demuxing. Make sure to set
- ``--demuxer-seekable-cache`` (or just use ``--cache``). The cache size
- might matter. If it's too small, a queue overflow will be logged, and
- backward playback cannot continue, or it performs too many low level
- seeks. If it's too large, implementation tradeoffs may cause general
- performance issues. Use ``--demuxer-max-bytes`` to potentially increase
- the amount of packets the demuxer layer can queue for reverse demuxing
- (basically it's the ``--video-reversal-buffer`` equivalent for the
- demuxer layer).
+ ``--cache=yes``. The cache size might matter. If it's too small, a queue
+ overflow will be logged, and backward playback cannot continue, or it
+ performs too many low level seeks. If it's too large, implementation
+ tradeoffs may cause general performance issues. Use
+ ``--demuxer-max-bytes`` to potentially increase the amount of packets the
+ demuxer layer can queue for reverse demuxing (basically it's the
+ ``--video-reversal-buffer`` equivalent for the demuxer layer).
- Setting ``--vd-queue-enable=yes`` can help a lot to make playback smooth
(once it works).
@@ -3547,7 +3546,8 @@ Demuxer
``--demuxer-max-back-bytes=<bytesize>``
This controls how much past data the demuxer is allowed to preserve. This
- is useful only if the ``--demuxer-seekable-cache`` option is enabled.
+ is useful only if the cache is enabled.
+
Unlike the forward cache, there is no control how many seconds are actually
cached - it will simply use as much memory this option allows. Setting this
option to 0 will strictly disable any back buffer, but this will lead to
@@ -3581,18 +3581,18 @@ Demuxer
buffer is only reduced when new data is read.
``--demuxer-seekable-cache=<yes|no|auto>``
- This controls whether seeking can use the demuxer cache (default: auto). If
- enabled, short seek offsets will not trigger a low level demuxer seek
+ Debugging option to control whether seeking can use the demuxer cache
+ (default: auto). Normally you don't ever need to set this; the default
+ ``auto`` does the right thing and enables cache seeking it if ``--cache``
+ is set to ``yes`` (or is implied ``yes`` if ``--cache=auto``).
+
+ If enabled, short seek offsets will not trigger a low level demuxer seek
(which means for example that slow network round trips or FFmpeg seek bugs
can be avoided). If a seek cannot happen within the cached range, a low
level seek will be triggered. Seeking outside of the cache will start a new
cached range, but can discard the old cache range if the demuxer exhibits
certain unsupported behavior.
- Keep in mind that some events can flush the cache or force a low level
- seek anyway, such as switching tracks, or attempting to seek before the
- start or after the end of the file.
-
The special value ``auto`` means ``yes`` in the same situation as
``--cache-secs`` is used (i.e. when the stream appears to be a network
stream or the stream cache is enabled).
@@ -4463,9 +4463,8 @@ Cache
Decide whether to use network cache settings (default: auto).
If enabled, use up to ``--cache-secs`` for the cache size (but still limited
- to ``--demuxer-max-bytes``). ``--demuxer-seekable-cache=auto`` behaves as if
- it was set to ``yes``. If disabled, ``--cache-pause`` and related are
- implicitly disabled.
+ to ``--demuxer-max-bytes``), and make the cached data seekable (if possible).
+ If disabled, ``--cache-pause`` and related are implicitly disabled.
The ``auto`` choice enables this depending on whether the stream is thought
to involve network accesses or other slow media (this is an imperfect
@@ -6431,7 +6430,7 @@ Miscellaneous
video. See ``--video-sync-adrop-size``. This mode will
cause severe audio artifacts if the real monitor
refresh rate is too different from the reported or
- forced rate. Sicne mpv 0.33.0, this acts on entire audio
+ forced rate. Since mpv 0.33.0, this acts on entire audio
frames, instead of single samples.
:display-desync: Sync video to display, and let audio play on its own.
:desync: Sync video according to system clock, and let audio play