core: allow changing filter filters at runtime

Add the "vf" command, which allows changing the video filter chain at
runtime. For example, the 'y' key could be bound to toggle deinterlacing
by adding 'y vf toggle yadif' to the input.conf.

Reconfiguring the video filter chain normally resets the VO, so that it
will be "stuck" until a new video frame is rendered. To mitigate this, a
seek to the current position is issued when the filter chain is changed.
This is done only if playback is paused, because normal playback will
show an actual new frame quickly enough.

If vdpau hardware decoding is used, filter insertion (whether it fails
or not) will break the video for a while. This is because vo_vdpau
resets decoding related things on vo_config().

1 files changed, 31 insertions, 0 deletions

diff --git a/DOCS/man/en/input.rst b/DOCS/man/en/input.rst
index bd62e65cd6..4acba49169 100644
--- a/DOCS/man/en/input.rst
+++ b/DOCS/man/en/input.rst
@@ -236,6 +236,37 @@ af_clr
     Remove all audio filters. (Conversion filters will be re-added
     automatically if needed.)
 
+vf set|add|toggle|del "filter1=params,filter2,..."
+    Change video filter chain.
+
+    The first argument decides what happens:
+
+    set
+        Overwrite the previous filter chain with the new one.
+
+    add
+        Append the new filter chain to the previous one.
+
+    toggle
+        Check if the given filter (with the exact parameters) is already
+        in the video chain. If yes, remove the filter. If no, add the filter.
+        (If several filters are passed to the command, this is done for
+        each filter.)
+
+    del
+        Remove the given filters from the video chain. Unlike in the other
+        cases, the second parameter is a comma separated list of filter names
+        or integer indexes. ``0`` would denote the first filter. Negative
+        indexes start from the last filter, and ``-1`` denotes the last
+        filter.
+
+    *EXAMPLE for input.conf*:
+
+    - ``a vf set flip`` turn video upside-down on the ``a`` key
+    - ``b vf set ""`` remove all video filters on ``b``
+    - ``c vf toggle lavfi=gradfun`` toggle debanding on ``c``
+
+
 Undocumented commands: tv_start_scan, tv_step_channel, tv_step_norm,
 tv_step_chanlist, tv_set_channel, tv_last_channel, tv_set_freq, tv_step_freq,
 tv_set_norm, dvb_set_channel, radio_step_channel, radio_set_channel,