bytedeco/javacv

Java2DFrameConverter getBufferedImage throws NullPointerException with crop filtered frame

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#1,621 opened on Apr 9, 2021

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 (8 comments) (0 reactions) (0 assignees)Java (1,583 forks)batch import
bughelp wanted

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Description

frame video filter:fps=fps=0.2**,crop=639:216:0:0** crop=639:216:0:0 will cause NullPointerExcepttion

**filter.push(frame);
Frame frameImg;
if ((frameImg = filter.pull()) != null) {
    if (frameImg.image != null) {
        log.info("frame image width:{} height:{}", frameImg.imageWidth, frameImg.imageHeight);
        log.info("save image to file:{}", filename);
        int type = Java2DFrameConverter.getBufferedImageType(frameImg);
        double gamma = type == BufferedImage.TYPE_CUSTOM ? 1.0 : inverseGamma;
        bufferedImage = converter.getBufferedImage(frameImg, gamma, flipChannels, null);
        ImageIO.write(bufferedImage, "jpg", new File(filename));
    }
}**

ERROR] 2021-04-09 13:04:58.306 [grab--0] Grabber - java.lang.NullPointerException at java.awt.image.ComponentColorModel.bitsHelper(ComponentColorModel.java:359) at java.awt.image.ComponentColorModel.(ComponentColorModel.java:273) at java.awt.image.ComponentColorModel.(ComponentColorModel.java:351) at org.bytedeco.javacv.Java2DFrameConverter.getBufferedImage(Java2DFrameConverter.java:639)

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Research direction
Inspect the stack trace: NullPointerException occurs in ComponentColorModel.bitsHelper and Java2DFrameConverter.getBufferedImage at line 639. The issue is triggered when a crop filter is applied to a video frame. Check if the frame after filtering has null image data or invalid dimensions. Examine the Java2DFrameConverter.getBufferedImage method to understand where the null pointer originates and ensure proper handling of cropped frames.
Tech stack
java
Domain
computer vision
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Mostly clear
Prerequisites
Java
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
50