bytedeco/javacv

I'm passing a Frame to a BufferedImage to get a Array of each RGB channel - is there a more direct path?

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#2,097 opened on Sep 14, 2023

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Description

I feel like I'm converting when I don't need to be, and that there is likely a much more direct path.

Input: A short lived org.bytedeco.javacv.Frame read from a FFmpegFrameGrabber.

Output: the image fully decoded and normalized in a very basic format of:

class DecodedImage(
    internal val width: Int,
    internal val height: Int,
    private val red: IntArray = IntArray(width * height),
    private val green: IntArray = IntArray(width * height),
    private val blue: IntArray = IntArray(width * height),
)

Ints per channel per pixel are a lot, but I need them for some later summing.

Right now I'm using a Java2DFrameConverter to convert the Frame to a BufferedImage, then reading out pixels from the BufferedImage -> Raster -> dataBuffer.

That seems... excessive. Is there a more direct way of blowing out a Frame to a fully flattened DecodedImage? I poked around in the Java2DFrameConverter, and it handles a lot of image formats.

Contributor guide

Research direction
Investigate the Frame class to determine if it directly exposes its underlying pixel buffers (e.g., byte buffers or IntBuffer) that can be accessed without conversion to BufferedImage. Consider using Frame.image or Frame.opaque fields to get raw data. Also review the Java2DFrameConverter source code to understand the conversion process and see if you can write a more direct extraction method that fills a DecodedImage directly from the Frame's data.
Tech stack
java
Domain
computer vision
Issue type
Research
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
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.
Clear
Prerequisites
Java
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70