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Videoreader jitter

Asked by Alexander Farley on 4 Jan 2012
Hi,
I'm loading a video using VideoReader and processing frame by frame. Occasionally, it looks like VideoReader repeatedly provides the same frame regardless of index. Eventually, the reader "catches up" and gives the correct frame.
The result is that the processed video looks jittery and choppy. The jittery loading seems to occur unpredictably.

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3 Answers

Walter Roberson
Answer by Walter Roberson
on 4 Jan 2012

VideoRecorder is not designed for "real-time" or precision timing. Please consider using the Image Acquisition Toolbox

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Walter Roberson
on 4 Jan 2012
What video file format is the pre-recorded video in? If it is in .avi then you can read it frame by frame using the VideoReader class.
Walter Roberson
on 4 Jan 2012
Sorry, somehow earlier I read your question as having to do with VideoRecorder instead of VideoReader. VideoReader should be able to read every frame.
Which MATLAB version are you using?
I'm using r2011a. The videos are in .wmv and .asf format. The VideoReader class basically works except for the problem mentioned above.

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Image Analyst
Answer by Image Analyst
on 6 Jan 2012

You're talking about extracting a single frame and displaying it in an axes, right? Not playing it as a movie and noticing some pauses or hangups? Are you sure the frame(s) in question are not in there two or three of multiple times in a row (like frames 14-18 are all the same)? Do you have some alternate way of viewing a frame at a time - like some other program?

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In addition: I initially thought this might be a hardware problem, but you can see the same problem in this video, created on a different computer:
http://youtu.be/Taxn9On4HVk
This makes me think it's a problem in my code or with VideoReader.
Image Analyst
on 17 Apr 2012
Can you upload one of the original input choppy videos and tell me what frame it pauses?
K E
on 26 Sep 2012
I am having problems with VideoReader appearing to read in a different number of frames each times a video file is read. I would love to know more about this problem if you figure it out.

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Ribas
Answer by Ribas
on 17 Apr 2012

Did you guys know the solution for this problem?
I am analysing video and when trying to read the same frame in different tests, it gets me different frames...

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No, I never figured out what causes this problem.

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