From 1194ecd154526fae3641bc6d10ea83d2d1d0f404 Mon Sep 17 00:00:00 2001 From: wm4 Date: Tue, 23 Jun 2020 20:46:52 +0200 Subject: 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). --- DOCS/man/options.rst | 37 ++++++++++++++++++------------------- 1 file changed, 18 insertions(+), 19 deletions(-) (limited to 'DOCS/man') 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=`` 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=`` - 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 -- cgit v1.2.3