Since version 3.1.0 you can play videos within experiment.
|You can also play videos in surveys.|
Here are some important tips:
You should not upload your video clips to PsyToolkit, but to the Google or Dropbox drive (or somewhere else), see below for howto.
Before the experiment starts, the video clips are loaded into the participant’s computer — they should ideally not be too big
Make sure the videos are of a reasonable size. You can resize them, but smaller videos load quicker
Videos can be shown similarly to other stimuli
Telling PsyToolkit where the video is stored
You need to create a videos section. In there, you need to specify the name of your video and an Internet link. In this case, I have uploaded two clips via Dropbox and shared the uploaded file with anyone with the link. I just got the link and added it to the scrip.
|The video link you get can be just copied. In reality, PsyToolkit will itself change ending dl=0 with raw=1|
videos clip1 https://www.dropbox.com/s/kzo7sx7hkdai16i/beetle.mp4?dl=0 clip2 https://www.dropbox.com/s/bzbs6qpk7ht9yyu/frog.mp4?dl=0
Making a video smaller makes sense
You can use video editing software to make your video smaller. For example, the default resolution for experiments is only 800x600, while videos often come in a much larger resolution. Even short videos can be big files. But you can make them much smaller. For example, Kdenlive and Openshot are free video editors. Load in your video clip and render it on a smaller resolution (e.g., 500x300 pixels). That makes a huge difference.
|The video clips in the demonstration below were taken on a mobile phone and edited with Kdenlive. They are both quite small files, which means participants do not need to wait long before they are loaded.|
Starting to play the video in a trial
In your task, you use show video to show the video similar to showing, for example, a bitmap or a rectangle.
Full documentation: https://www.psytoolkit.org/doc3.3.0/syntax.html#task-show-video
In the example below, without further parameters, it simply plays the video
task my_task show video clip1
You can give show video all sorts of parameters to resize the video, and to show it on different locations. Here is an example that resizes the video to 50% of its normal size.
task my_task show video clip2 0 0 50
Play sound or not
Use the videocontrol instruction
task my_task videocontrol clip1 mute
Rewind and pause
task my_task videocontrol clip1 rewind
task my_task videocontrol clip1 pause
Stop and clear a video from screen
For this, you simply use the clear instruction as for other stimuli (see the demonstration code below)
Keep looping or not
You can keep repeating your video once it reached the end.
task my_task videocontrol clip1 loop
In the demonstration, you see how two video clips are being loaded and played
The PsyToolkit code
videos (1) clip1 https://www.dropbox.com/s/kzo7sx7hkdai16i/beetle.mp4?dl=0 (2) clip2 https://www.dropbox.com/s/bzbs6qpk7ht9yyu/frog.mp4?dl=0 (3) task videoplay (4) keys b (5) videocontrol clip2 mute (6) videocontrol clip1 loop (7) videocontrol clip2 loop (8) show video clip1 -200 0 50 (9) show video clip2 200 0 50 (10) delay 2000 (11) show text "now click the B key to end" 0 -250 (12) readkey 1 10000 (13) clear -1 -2 (14) block vi (15) tasklist (16) videoplay 1 (17) end (18)
|1||We need a videos section to tell PsyToolkit where the videos are|
|2||You can choose a name, followed by an Internet URL. In this case, it is the shared link you get from Dropbox. Internally, PsyToolkit will replace the dl=0 with raw=1 to make sure it is downloadable|
|3||Same for a separate video clip. You can give any name to these clips, just as for bitmap stimuli|
|4||Now you have a task section, we create a simple demo task|
|5||We will use one keyboard button for this demo, the b|
|6||We set clip2, which has sound, to mute, so that we do not need to listen to it. Clip1 just happens to have no sound anyway|
|7||We make sure the clip keeps repeating (loop)|
|8||Smae for clip2|
|9||Now we show clip1 200 pixels left from screen center. The 50 means that the video is scaled to 50% of its original size.|
|10||Now we show clip1 200 pixels right from screen center.|
|11||Do nothing for 2 seconds (2000 milliseconds)|
|12||Now we show a text giving an instruction to the participant|
|13||We wait for the key press|
|14||Now we clear the two last showed stimuli (we could also have written clear 1 2)|
|15||Now we start a block|
|16||We tell PsyToolkit what the tasks are|
|17||We have only one task and we use it 1 trial|
|18||End of tasklist|