I am writing a program for audio-visual experiments, which will present a pre-generated list of audio-only and video-with-audio stimuli to experiment subjects. I have decided to use PyQT and Phonon for this, despite the fact that I'm fairly new to writing QT-based programs (and GUI programming in general).
The issue I'm having is that, when the previous file played was video (.mov in this case), and the current file is audio-only (.wav file), the image from the last frame of the video file remains on the screen while the audio file is playing. The video image remains until the next .mov file rolls around in the stimulus list.
Is there a way to clear the Phonon screen, in order to show just an empty black screen while the audio-only files are playing? I've done a fair bit of poking around with Google, and though this question has been asked by a number of people on different forums, it seems to have gone unanswered.
Any suggestions will be greatly appreciated!
This seems to be a bug, or missing feature, and it's hard to come up with a good workaround.
One somewhat hacky solution is to force a resize of the video widget:
size = self.video.size()
self.video.resize(0, 0)
self.video.resize(size)
but I wouldn't bet on this working on all platforms.
A more reliable workaround would be to put the video-widget inside a container widget with a black background, and then simply hide/show the video-widget when stopping/starting the media.
Related
I am trying to develop a basic experiment in the PsychoPy Builder where a silent movie plays in the background while I go through a .csv list to play a sequential series of about 100 very short sounds (about 300 milliseconds each). When I play the .csv list by itself, the sounds play perfectly like I would expect, but when I add the video component, only the first sound in the list will play and it won’t play the entire list of sounds. The video does continue to play, but somehow seems to interfere with the sound component or reading through the .csv file.
I tried deactivating the audio of the silent movie because I thought this could interfere with the sound component, but this does not resolve the issue.
It seems the program is waiting for the video to end before it can repeat the loop and go to the next sound in the list, but instead the program just closes as soon as the video ends. Furthermore, I want the single video to be playing while the sound component loops through the list, but I don't know how to apply the loop only to one component and not the video component that is supposed to play simultaneously with the sounds.
I feel like this should be very easy to achieve, yet I could not find someone with a similar issue when googling a solution. Your help is much appreciated.
I have an extremely simple application for a Raspberry Pi. (It's an educational kiosk for a children's museum if anyone cares.) In python, I have an infinite loop in a thread reading a line from a serial port. Based on the input, I display one of 14 different jpg images. I am not putting all the code here, but it's a very bare-bones GDK application. I have an Arduino feeding the serial port the information to cycle through all the images for debug purposes. In response to the input, I do the following:
self.CurrentImage.set_from_file("image.jpg") # the name here is one of 14
Not to anyone's great surprise, this works. But as I let the Arduino hammer at the input, the screen would randomly show a white image and nothing again after. I checked the standard out window and the data was still coming and the images still being read. And when I say random I mean that at some point in the input-and-display process, it stops displaying. There are no errors being reported. Sometimes I might get 4-5 images in sequence before it dies, or I might make it through the list twice. It's simply not deterministic. My mind wandered to thinking maybe I'm not clearing first and having a memory leak. I made the following amendment:
self.CurrentImage.clear()
self.CurrentImage.set_from_file("image.jpg")
The problem persisted. I decided to scrap the method and go for something that didn't involve reloading images. At startup I created a separate GTK Image widget for each file. Then in response to the input data, I did this:
self.CurrentImage.hide()
self.CurrentImage = self.AlphaImage # or one of the other 13 Images I created
self.CurrentImage.show()
The nice thing about this method is that the image displays much faster. The first method had the screen briefly go white as the image was loaded. However, once again, after a random number of image switches, the window goes white. Diagnostic output shows that the loop is happily reading data and selecting images.
In the original version where I loaded images as needed, there was exactly one widget on the window. So it's not possible that another widget is covering it. The second version has an Image widget for each jpg file. If one is covering another, I should still at least see that image.
I'm good at thinking outside the box, but I admit that Linux is a weak area for me. Nothing is occurring to me to try to make this work. I'd whinge that I'm under time pressure here and children will be disappointed... but it was supposed to be done before Christmas and I only got the final art yesterday. That reminds me that there's one final note and the reason I thought my first method was failing: I created temporary graphics of my own that was one word of black text on a white background. Those images displayed without problem until the screensaver kicked in.
I'm open to any suggestion as to how to track this down and fix it.
Thanks to Sylvester, I figured this one out. The problem isn't how I was updating the images, it was where I was doing it. In the thread catching the serial input was not the place to do it. I reduced the thread to simply reading the line, then did the following:
GLib.idle_add( self.updateImage, lineInput )
then in the function updateImage I did the business logic of selecting the correct image and updating. Problem solved.
I am new to game development. I am trying to start high and make a 3D RPG. I know the road is not gonna be easy. That is why i decided to use Ursina and python to make my game.
However i wanna add a cutscene showing a Backstory. I have the video in mp4 format but i cannot seem to know how to play it inside the game with Ursina.
Anyhelp will be much appreciated.
(Side question : do you think Ursina is good for a beginner in 3D gaming? If i want to publish my game on my website, isn't it better for me to learn javascript ? I read about Unity but it is too big to download for a little side project)
You can set the video as a texture of any element. You'll want to fix it to the UI using its parent attribute and you have to load the sound separately from the same file (as described in the Panda3D documentation).
from ursina import *
app = Ursina()
video = 'video.mp4'
video_player = Entity(model='quad', parent=camera.ui, scale=(1.5, 1), texture=video)
video_sound = loader.loadSfx(video)
video_player.texture.synchronizeTo(video_sound)
video_sound.play()
app.run()
The above code assumes that the video file is in the same folder as the Python script.
Well, I don't think there is a way to do that. the closest thing you can do to that is having a folder filled with all the frames of your video in .png or .jpg files, then adding a quad to the world and changing the texture of it to the next frame every fraction of a second depending on the framerate. this, however would make your computer l a g. trust me, I've tried it. it would probably be better to have a separate window with some sort of module that plays .mp4 files for playing the file.
In other words, there is no feasible way to do that.
From Entity Basics in the documentation:
e4 = Entity(model='cube', texture='movie_name.mp4') # set video texture
I wanted to use Python to create animations (video) containing text and simple moving geometric objects (lines, rectangles, circles and so on).
In the book titled "Python 2.6 Graphics Cookbook" I found examples using Tkinter library. First, it looked like what I need. I was able to create simple animation but then I realized that in the end I want to have a file containing my animation (in gif or mp4 format). However, what I have, is an application with GUI running on my computer and showing me my animation.
Is there a simple way to save the animation that I see in my GUI in a file?
There is no simple way.
The question Programmatically generate video or animated GIF in Python? has answers related strictly to creating these files with python (ie: it doesn't mention tkinter).
The question How can I convert canvas content to an image? has answers related to saving the canvas as an image
You might be able to take the best answers from those two questions and combine them into a single program.
I've accomplished this before, but not in a particularly pretty way.
Tl;dr save your canvas as an image at each step of the iteration, use external tools to convert from image to gif
This won't require any external dependencies or new packages except having imagemagick already installed on your machine
Save the image
I assume that you're using a Tkinter canvas object. If you're posting actual images to the tk widgets, it will probably be much easier to save them; the tk canvas doesn't have a built-in save function except as postcript. Postscript might actually be fine for making the animation, but otherwise you can
Concurrently draw in PIL and save the PIL image https://www.daniweb.com/software-development/python/code/216929/saving-a-tkinter-canvas-drawing-python
Take a screenshot at every step, maybe using imagegrab http://effbot.org/imagingbook/imagegrab.htm
Converting the images to to an animation
Once the images are saved, I used imagemagick to dump them into either a gif, or into a mpg. You can run the command right from python using How to run imagemagick in the background from python or something similar. It also means that the process is implictely run on a separate thread, so it won't halt your program while it happens. You can query the file to find out when the process is done.
The command
convert ../location/*.ps -quality 100 ../location/animation.gif
should do the trick.
Quirks:
There are some small details, and the process isn't perfect. Imagemagick reads files in order, so you'll need to save the files so that alphabetical and chronological line up. Beware that the name
name9.ps
Is alphabetically greater than
name10.ps
From imagemagick's point of view.
If you don't have imagemagick, you can download it easily (its a super useful command-line tool to have) on linux and mac, and cygwin comes with it on windows. If you're worried about portability... well... PIL isn't standard either
There is a way of doing that, with the "recording screen method", this was explained in other question: "how can you record your screen in a gif?".
Click the link -->LICEcap : https://github.com/lepht/licecap
They say that it's free software for Mac (OS X) and Windows
You could look at Panda3D, but it could be a little over killed for what you need.
I would say you can use Blender3d too but i'm not really sure of how it works. Someone more experimented then me could tell you more about this.
I am starting out on a project in which I need to build a customized annotation tool for movies and video. Some person (not technically minded) will need to pop open a GUI that I create, open either a video file or a directory of frames that result from chopping up a video file, and then use a window (much like QuickTime or VLC player, etc., i.e. a video window with a simple slider bar allowing the user to move back and forth at will). In this window, the user will be able to click on interesting points, give them semantic labels and meta-data (such as whether or not the point is occluded by something else in the picture), and then basically "press go" and start a tracker. The tracker will follow the points, frame by frame and the user can press the space bar or something to move forward and backward. The idea is to allow the human to intervene any time the tracker gets confused, but hopefully the tracker works well enough that humans don't have to hand-label every frame in an entire multi-thousand frame video sequence.
I am planning to do this all in Python, (a) because it is the language I know best for non-trivial programming, (b) I have easy access to both OpenCV Python (for image processing algorithms) and PyQt which seems to have a powerful enough GUI toolbox for what I want to do and (c) some other aspects of this same project are being developed by other programmers to work in Python and with MySQL databases. Python just seems like the natural choice to streamline it all together.
I am experienced using computer vision algorithms for the tracking, and I am reasonably sure that I can figure out simple PyQt GUI devices for making points clickable, buttons, entering simple text data, etc. However, the part I am having trouble understanding is how to actually construct my own video window with a slider bar that either moves ahead according to a frame's number or else is actually manipulating a video file. Can I leverage other movie players like VLC from within PyQt when programming in Python? Any suggestions or links that describe similar movie/video editing GUIs and how to develop them at home would be greatly appreciated.
Qt(PyQt) has a good multimedia support via Phonon module. You can easily use that module to achieve Video window, it can provide an easy-to-use video player and you can get playing position etc.