Hi everyone! I want to do an EEG experiment using the Psychtoolbox as a way to present my stimulus, but I can't make it function properly. Does anyone know how to present videos using this toolbox? I've already test demos, but they didn't work. I really need help.
Nastassja
I am somewhat experienced with the Psychtoolbox, and I may or may not be able to help. What kind of videos are you looking to play? Are they films (e.g. a scene from a television show), or are they more abstract (e.g. a circle that increases in size)?
Hi Joseph! Thanks for the reply! They are films (Youtube videos).
Hi Nastassja, I'd recommend you run and study the several Demos in the Psychtoolbox (PTB) package (~/PsychDemos). If you're already familiar with programming in Matlab, then that should be enough to get you started. Every command in the Psychtoolbox is also well documented (usually type 'help' followed by the relevant command name). In the case of the 'Screen' command, simply type 'Screen' at the Matlab prompt for a list of available Screen subcommands. If you type Screen( '…?' ) where … refers to the relevant subcommand, you'll get more details on that specific subcommand. If all else fails, or if you think there is something wrong with the PTB, you can always post questions on the PsychToolbox forum (http://tech.groups.yahoo.com/group/psychtoolbox/), but since this all pro bono, I'd recommend posting judiciously.
As for your specific question of presenting YouTube videos, you'll likely need to use a conversion utility to bring the relevant videos into a format that PTB can handle. As I'm a consultant-for-hire, I'd be happy to provide you with any help you need including video conversion and PTB programming.
Cheers,
Stéphane
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Hi Stéphane. I downloaded Youtube videos in .mov format and tried to play them using the SimpleMovieDemo (replacing the default video provided...). It was the only function that I was able to play video with. Nevertheless, it just functioned if the movie was in the folder "QuickTime Demos" and even so it is played wrong (in an "accelerated" mode).
Moreover, I already tested some Demos, but some parameters are missing and, even reading the help docs, I don't understand what is going wrong (I'm getting familiarized with MATLAB/PTB recently...).
Anyway, thanks for the help!
Cheers!
As far as I can tell, you're dealing with a path issue for the movie location, and probably with vertical refresh syncing issue for the 'accelerated' mode.
Consider hiring our services if you'd like fast and comprehensive solutions to your problem!
Cheers
Stéphane
Hi there Nastassja,
Although I understand this post is a few years old, the question you had is more or less my exact question.
Can you please tell us a bit about how you got on at the end and what sources of information you found most helpful for making video work in Psychtoolbox.
Many thanks,
Victor
Hi Victor!
I have used the functions "OpenMovie" and "PlayMovie" with the "Screen" function to play videos using PTB. A detail: it only worked when I used the .mov video format (so, you have to have QuickTime installed). It didn't worked with .avi files ((I don't know why...). Even so, if you don't make it work, you can send me your email by DM and I can send you the piece of the script I used to do the job!
Greetings,
Nastassja
Hi Ka-Lon Sou,
I'm not using PTB recently, but according my experience, it has a lot of minor errors that can occur if you don't follow the PTB installation instructions exactly as they are written (and you have to be strictly exact about it). So, try to uninstall and reinstall PTB after installing GStreamer. Maybe it will work...
Cheers,
Nastassja
Hi Ka-Lon Sou,
Sorry relive a very old topic but did you ever find a solution to your problem ? I am having exactly the same one.
