Kieran Maraj

I'm working on a patch that allows a video to be played back a frame at a time, that allows for jumping from different parts of the video file to another, and that allows for the video to be scaled while maintaining its aspect ratio.

The issue I am running into is that the farther into the video file I get, the longer the render takes. For example, at the very start of a 1080p video, I get nearly instant rendering when moving from one frame to the next. At around 500-600 frames into the video, there's a noticeable delay between hitting the button to move to the next frame and the rendering of said frame. The delay gets worse the higher the number of the frame.

I'm using jit.movie with the viddll engine and have tested this with mov and mp4 formats on OS X 10.9.5 and the issue is persistent across file formats.

Is this an inherent limitation of frame by frame playback of the jit.movie object or might there be an error in my patching?

videoToFilmJuly24.maxpat

The issue I am running into is that the farther into the video file I get, the longer the render takes. For example, at the very start of a 1080p video, I get nearly instant rendering when moving from one frame to the next. At around 500-600 frames into the video, there's a noticeable delay between  hitting the button to move to the next frame and the rendering of said frame. The delay gets worse the higher the number of the frame.

Is this an inherent limitation of frame by frame playback of the jit.movie object or might there be an error in my patching? 

Hello,
I'm working on a patch that allows a video to be played back a frame at a time, that allows for jumping from different parts of the v

jitter-scrubbing-slows-down-as-video-file-progresses

your patch can be made much simpler and more efficient by using modern Jitter techniques. most importantly, you want to enable @output_texture 1 on your jit.movie. for aspect ratio stuff, you can simply use jit.gl.cornerpin. for frame scrubbing, you can simply use jit.movie @position attribute, which takes a floating point value between 0 and 1.

if you're still having problems, i would try avf engine and see if that functions better than viddll. lastly, for scrubbing files, you want to use a codec that doesn't use temporal compression. prores422 or photo-jpeg are recommended.

hello. 

your patch can be made much simpler and more efficient by using modern Jitter techniques. most importantly, you want to enable @output_texture 1 on your jit.movie. for aspect ratio stuff, you can simply use jit.gl.cornerpin. for frame scrubbing, you can simply use jit.movie @position attribute, which takes a floating point value between 0 and 1.

if you're still having problems, i would try avf engine and see if that functions better than viddll. lastly, for scrubbing files, you want to use a codec that doesn't use temporal compression. prores422 or photo-jpeg are recommended.

Thanks for the response! I'm developing the patch as a tool for filmmakers to use to transfer digital video on to analogue film. For that reason, there are a few limitations I need to work within. That includes needing to scrub/navigate the video file by exact frames as opposed to the float value. I had also previously tried using jit.gl.cornerpin, but it didn't work the way I needed it to for scaling beyond the bounds of a matrix.

But I was able to get my patch working the way I intended by using a qmetro to bang the jit.move and jit.gl.render, as opposed to using the bang routed from the jit.movie's seeknotify message. I also found that mp4 files worked with the viddll engine and not avf, despite the temporal compression. I'm trying to make it as accessible as possible, so while I'll include instructions to encode with non-temporal compressing codecs, it's nice to know that it can still work.

I've attached the updated patch here for anyone interested :)

videoToFilmJuly24.2.maxpat

Thanks for the response! I'm developing the patch as a tool for filmmakers to use to transfer digital video  on to analogue film. For that reason, there are a few limitations I need to work within. That includes needing to scrub/navigate the video file by exact frames as opposed to the float value. I had also previously tried using jit.gl.cornerpin, but it didn't work the way I needed it to for scaling beyond the bounds of a matrix.

But I was able to get my patch working the way I intended by using a qmetro to bang the jit.move and jit.gl.render, as opposed to using the bang routed from the jit.movie's seeknotify message. I also found that mp4 files worked with the viddll engine and not avf, despite the temporal compression. I'm trying to make it as accessible as possible, so while I'll include instructions to encode with non-temporal compressing codecs, it's nice to know that it can still work.  

Jitter Scrubbing Slows Down as Video File Progresses