# MovieStim3 and VlcMovieStim not working

**URL:** <https://discourse.psychopy.org/t/moviestim3-and-vlcmoviestim-not-working/29900>\
**Category:** Builder\
**Tags:** movies\
**Created:** [July 7, 2022, 1:26pm UTC](https://discourse.psychopy.org/t/moviestim3-and-vlcmoviestim-not-working/29900 "2022-07-07T13:26:18Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Brian\_Man](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.psychopy.org/brian_man/32/34484_2.png) [@Brian\_Man](https://discourse.psychopy.org/u/Brian_Man)\
**Post date:** [July 7, 2022, 1:26pm UTC](https://discourse.psychopy.org/t/moviestim3-and-vlcmoviestim-not-working/29900/1 "2022-07-07T13:26:18Z")

</div>

Hi all,

I am currently designing and audiovisual experiment where I need to present synchronous audio and visual stimuli. Due to the limitations of the .mp4 container I will be presenting the video as an mp4 and the audio as a separate .wav file.

However, I recently started experimenting with play the video only using MovieStim3 and VlcMovieStim and am met with different problems:

1. VlcMovieStim  
I used the builder to design this. I set vlc as backend and am met with this error:

```auto
@vlc.CallbackDecorators.VideoLockCb
NameError: name 'vlc' is not defined

```

I have read several other forums that the location of the vlc libraries were installed wrongly in Python? But I also read from somewhere that the problem has been fixed. What is the issue behind this and how do I fix it? I have already installed moviepy and python-vlc.

1. MovieStim3  
There seems to be a very serious frame drop issue:

```auto
8.8732 WARNING 0.60297070001252: Video catchup needed, advancing self._nextFrameT from 0.0 to 0.02
8.8733 WARNING 0.6029957999708131: Video catchup needed, advancing self._nextFrameT from 0.02 to 0.04
8.8733 WARNING 0.6030063999933191: Video catchup needed, advancing self._nextFrameT from 0.04 to 0.06
8.8733 WARNING 0.6030157000059262: Video catchup needed, advancing self._nextFrameT from 0.06 to 0.08
8.8733 WARNING 0.6030267999740317: Video catchup needed, advancing self._nextFrameT from 0.08 to 0.1
8.8733 WARNING 0.6030380000011064: Video catchup needed, advancing self._nextFrameT from 0.1 to 0.12000000000000001
8.8733 WARNING 0.6030481000198051: Video catchup needed, advancing self._nextFrameT from 0.12000000000000001 to 0.14
8.8733 WARNING 0.6030579999787733: Video catchup needed, advancing self._nextFrameT from 0.14 to 0.16
8.8733 WARNING 0.6030697000096552: Video catchup needed, advancing self._nextFrameT from 0.16 to 0.18
8.8733 WARNING 0.6030799999716692: Video catchup needed, advancing self._nextFrameT from 0.18 to 0.19999999999999998
8.8733 WARNING Max reportNDroppedFrames reached, will not log any more dropped frames

```

Does this have to do with the video files being too much for it to read? Currently the files are 1920x1080 at 50fps and ~50000kb/s (file size 22MB). If so would compressing the file resolve this issue? If so, what is the recommended details for psychopy to play?

I tried myself to play it via moviepy on a separate script outside of pyschopy and using a simple ‘clip = VideoFileClip(‘0001.mp4’);ipython\_display(clip)’. This took around 4seconds to build. But was able to play very smoothly after building was completed.

I would really appreciate feedback!