VSA-Mainapp-Release

JXL Compression Guide

VSA provides image compression functionality using the JPEG XL (JXL) format. This guide explains how to configure and use JXL compression.

What is JPEG XL?

JPEG XL is a next-generation image format with the following features:

VRChat screenshots are typically saved as PNG, but JXL compression can reduce file size by over 50%.

Accessing the Compression Screen

Click “JXL Compression” in the sidebar to open the compression screen.

The screen has two tabs:

Auto Compression

Automatically executes compression on a regular schedule.

Schedule Settings

Setting Description
Interval Compression interval (monthly)
Start Day Which day of the month to start
Next Run Next scheduled execution date

Background Processing Settings

Setting Description
Auto Start Automatically start when conditions are met
Start Trigger File count threshold for auto start
Monitor Interval Folder monitoring interval (minutes)
Consider VRChat State Pause while VRChat is running

VRChat Active Behavior

When “Consider VRChat State” is enabled, compression processing pauses while VRChat is active. This prevents performance degradation during gameplay.

Snooze Feature

When a compression reminder appears, you can select from the following snooze options:

Manual Compression

Select any folder and execute compression.

Steps

  1. Select Input Folder: Folder containing PNG files to compress
  2. Select Output Folder: Destination for JXL files
  3. Select Processing Mode: Batch or background processing
  4. Start Compression: Click the “Start Compression” button

Processing Modes

Batch Processing:

Background Processing:

Checking Progress

During processing, the following information is displayed:

Extracting JXL Files

You can restore compressed JXL files back to original PNG.

  1. Open the “JXL Extract” section in the manual compression tab
  2. Select JXL file or folder to extract
  3. Select output destination folder
  4. Click “Start Extraction”

The extracted PNG files will have the original metadata restored.

Compression Settings

You can change detailed JXL compression settings in the settings screen.

Effort

Value Description
0-3 Fast but lower compression ratio
4-6 Balanced
7-9 Slow but high compression ratio

The default value is 7, which balances compression ratio and processing speed.

Lossless Compression

VSA only supports lossless (reversible) compression. This means:

Compression Results

After compression completes, the following information is displayed:

A metadata.json file is also generated in each folder, recording compression history.

Important Notes

Compression While VRChat is Running

Running compression while playing VRChat may cause the following issues:

It is recommended to exit VRChat before running compression whenever possible.

Disk Space

During compression, both input and output files exist, so additional disk space is temporarily required.

Ensure sufficient free space (approximately 1.2x the input file size).

Original File Handling

Original PNG files are not automatically deleted after compression. If you want to save disk space, manually delete them after confirming compression completed successfully.

Troubleshooting

Compression Not Progressing

  1. Check disk space: Is there sufficient free space?
  2. Check file permissions: Do you have read/write permissions?
  3. Check target files: Do PNG files exist?

Low Compression Ratio

Images that are already efficiently compressed or have simple content may have lower compression ratios.

Metadata Lost

Saving in formats other than JXL may cause VSA metadata to be lost. Always use VSA’s compression feature.