CODEWITHSUNDEEP
pythonvideovlcplaybacklibvlc
aescript
aescript

Reputation: 1925

Python VLC - get position polling rate work arounds

Im using Python VLC to build a custom playback app in pyqt. I have painted a nice custom slider to track along with the video, but hit a bit of an annoying problem.

No matter how often I tell my slider to update, it's quite glitchy (jumping every 1/4 second or so) and looks choppy (just the timeline, not the video).

Digging into it, I learned that

media_player.get_position()

Has quite a low polling rate. It returns the same value quite often then jumps a large amount the next time it gives a new value.

So right now I ran some test metrics and found it tends to update every 0.25-0.3 seconds. So now I have a system that basicay stores the last value and last system time a new value came in, and the last jump-distance in returned values and does some basic math with those things to fake proper linear timeline data between polls to make a very smooth timeline slider.

The problem is this assumes my value of every 0.25-0.3 seconds is consistent across machines, hardware, frame rates of videos etc.

Does anyone know of a better fix?

Maybe a way to increase the poll rate of VLC to give me better data to begin with - or some better math to handle smoothing?

Thanks

Upvotes: 6

Views: 2796

Answers (2)

Rolf of Saxony
Rolf of Saxony

Reputation: 22443

Using get_position() returns a value between 0.0 and 1.0, essentially a percentage of the current position measured against the total running time.
Instead you can use get_time() which returns the current position in 1000ths of a second.
i.e.
print (self.player.get_time()/1000) would print the current position in seconds.

You could also register a callback for the vlc event EventType.MediaPlayerTimeChanged, as mentioned in the other answer given by @mtz
i.e. Where self.player is defined as:

    self.Instance = vlc.Instance()
    self.player = self.Instance.media_player_new()

Then:

    self.vlc_event_manager = self.player.event_manager()
    self.vlc_event_manager.event_attach(vlc.EventType.MediaPlayerTimeChanged, self.media_time_changed)

def media_time_changed(self,event):
    print (event.u.new_time/1000)
    print (self.player.get_time()/1000)
    print (self.player.get_position())

Upvotes: 1

mfkl
mfkl

Reputation: 2159

Try using the libvlc_MediaPlayerPositionChanged or libvlc_MediaPlayerTimeChanged mediaplayer events instead.

https://www.videolan.org/developers/vlc/doc/doxygen/html/group__libvlc__event.html#gga284c010ecde8abca7d3f262392f62fc6a4b6dc42c4bc2b5a29474ade1025c951d

Upvotes: 0

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