manpage: some more backward playback edits

This commit is contained in:
wm4 2019-06-02 02:24:43 +02:00
parent f439064e7f
commit 7ed4d77a97
1 changed files with 22 additions and 12 deletions

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@ -496,8 +496,8 @@ Playback Control
Tuning: Tuning:
- Remove all ``--vf``/``--af`` filters you have set. Disable deinterlacing. - Remove all ``--vf``/``--af`` filters you have set. Disable hardware
Disable idiotic nonsense like SPDIF passthrough. decoding. Disable idiotic nonsense like SPDIF passthrough.
- Increasing ``--video-reversal-buffer`` might help if reversal queue - Increasing ``--video-reversal-buffer`` might help if reversal queue
overflow is reported, which may happen in high bitrate video, or video overflow is reported, which may happen in high bitrate video, or video
@ -505,17 +505,20 @@ Playback Control
increase ``--hwdec-extra-frames`` instead (until you get playback without increase ``--hwdec-extra-frames`` instead (until you get playback without
logged errors). logged errors).
- The demuxer cache is essential for backward demuxing. If it's too small, - The demuxer cache is essential for backward demuxing. Make sure to set
a queue overflow will be logged, and backward playback cannot continue, ``--demuxer-seekable-cache`` (or just use ``--cache``). The cache size
or it performs too many low level seeks. If it's too large, implementation might matter. If it's too small, a queue overflow will be logged, and
tradeoffs may cause general performance issues. Use ``--demuxer-max-bytes`` backward playback cannot continue, or it performs too many low level
to potentially increase the amount of packets the demuxer layer can queue seeks. If it's too large, implementation tradeoffs may cause general
for reverse demuxing (basically it's the ``--video-reversal-buffer`` performance issues. Use ``--demuxer-max-bytes`` to potentially increase
equivalent for the demuxer layer). the amount of packets the demuxer layer can queue for reverse demuxing
(basically it's the ``--video-reversal-buffer`` equivalent for the
demuxer layer).
- ``--demuxer-backward-playback-step`` also factors into how many seeks may - ``--demuxer-backward-playback-step`` also factors into how many seeks may
be performed, and whether backward demuxing could break due to queue be performed, and whether backward demuxing could break due to queue
overflow. overflow. If it's set too high, the backstep operation needs to search
through more packets all the time, even if the cache is large enough.
- Setting ``--demuxer-cache-wait`` may be useful to cache the entire file - Setting ``--demuxer-cache-wait`` may be useful to cache the entire file
into the demuxer cache. Set ``--demuxer-max-bytes`` to a large size to into the demuxer cache. Set ``--demuxer-max-bytes`` to a large size to
@ -524,7 +527,7 @@ Playback Control
cache. cache.
- If audio artifacts are audible, even though the AO does not underrun, - If audio artifacts are audible, even though the AO does not underrun,
increasing ``--audio-reversal-buffer`` might help in some cases. increasing ``--audio-backward-overlap`` might help in some cases.
``--video-reversal-buffer=<bytesize>``, ``--audio-reversal-buffer=<bytesize>`` ``--video-reversal-buffer=<bytesize>``, ``--audio-reversal-buffer=<bytesize>``
For backward decoding. Backward decoding decodes forward in steps, and then For backward decoding. Backward decoding decodes forward in steps, and then
@ -533,8 +536,13 @@ Playback Control
unbounded resource usage; during normal backward playback, it's not supposed unbounded resource usage; during normal backward playback, it's not supposed
to hit the limit, and if it does, it will drop frames and complain about it. to hit the limit, and if it does, it will drop frames and complain about it.
Use this option if you get reversal queue overflow errors during backward
playback. Increase the size until the warning disappears. Usually, the video
buffer will overflow first, especially if it's high resolution video.
This does not work correctly if video hardware decoding is used. The video This does not work correctly if video hardware decoding is used. The video
frame size will not include the referenced GPU and driver memory. frame size will not include the referenced GPU and driver memory. Some
hardware decoders may also be limited by ``--hwdec-extra-frames``.
How large the queue size needs to be depends entirely on the way the media How large the queue size needs to be depends entirely on the way the media
was encoded. Audio typically requires a very small buffer, while video can was encoded. Audio typically requires a very small buffer, while video can
@ -591,6 +599,8 @@ Playback Control
Setting this to a very low value or 0 may make the player think seeking is Setting this to a very low value or 0 may make the player think seeking is
broken, or may make it perform multiple seeks. broken, or may make it perform multiple seeks.
Setting this to a high value may lead to quadratic runtime behavior.
Program Behavior Program Behavior
---------------- ----------------