Video library: speed() in conjunction with mouseX is delivering jittery playback, and I can't use -1

MobiusCurve

I have two questions with the below code:

import processing.video.*;
Movie myMovie;

void setup() {
  size(600, 400);
  frameRate(30);
  myMovie = new Movie(this, "1.mp4");
  myMovie.loop();
}

void draw() {
  if (myMovie.available()) {
    myMovie.read();
    float  x1 = map(mouseX, 0, width, 0, 3);
    myMovie.speed(x1);
  }
  image(myMovie, 0, 0);
} 

1) How can I make the video play backwards? If I write the following code, I get this error message: (Processing core video:14294): GStreamer-CRITICAL **: get_segment_set_seek: assertion 'start <= stop' failed

    float  x1 = map(mouseX, 0, width, -1, 3)

2) Is there a way to make the playback a little more smooth? There is a lengthy delay between when the mouse is moved and when the video changes playback speeds.

GoToLoop

There is a lengthy delay between when the mouse is moved and when the video changes playback speeds.

Since both of your map() & speed() depend on available(), response time isn't frameRate(30);.
I'd also replace image() w/ set() for a tiny bit performance gain. B-)

GoToLoop

How can I make the video play backwards?

I don't think that library got such feature. :(
If you got lotsa RAM, you might try to get() each read() into some List<PImage>.
Once playback is finished, display each PImage backwards:

// forum.processing.org/two/discussion/13557/
// video-library-speed-in-conjunction-with-mousex-
// is-delivering-jittery-playback-and-i-can-t-use-1

// 2015-Nov-18

import java.util.List;
final List<PImage> frames = new ArrayList<PImage>();

import processing.video.Movie;
Movie mv;

void movieEvent(Movie m) {
  m.read();
  frames.add(m.get());
}

MobiusCurve

Hi GoToLoop,

Thanks for your response.

After doing a little more reading, it looks like the inability to play the video backwards is because of the codec I'm using--so that solves that issue.

I'm still a little cofused as to how to solve the jittery playback though.

I understand that what you're saying is that both my map() and speed() depend on available(), and so it's slowing things down. Is there a way to solve that problem?

Thanks!

GoToLoop

• I mean that while draw() is called back @ ~30 FPS -> frameRate(30);, map()'s calculation + speed() modification only happen once a new frame becomes available().
• That is, even though we're continuously moving the mouse, its mouseX will only be read once per Movie's read().
• Obviously if you don't want those calculations & modifications bound to available(), you should place them outside its if () block.
• Of course, that doesn't necessarily mean it's gonna fix the slowdown you're getting.

MobiusCurve

Thanks for your feedback, and for clarifying your last post.

Unfortunately, I've tried moving them out of the if block, but it still doesn't seem to solve the problem:

void draw() {
  float  x1 = map(mouseX, 0, width, 0, 3);
  myMovie.speed(x1);
  if (myMovie.available()) {
    myMovie.read();
  }
  image(myMovie, 0, 0);
}