Linux: Fixing Invisible Video Bug In Game Engine 1.0.1

Aug 10, 2025 by Sebastian Müller 55 views

Bug Report: Videos Not Showing, Only Audio on Linux

Hey guys, we've got a bug report here about videos not displaying correctly on Linux, and I wanted to break it down and make sure we get this fixed.

Issue Summary

The core issue is that when playing videos in a game built with version 1.0.1 of the engine on Linux, you only hear the audio – the video itself is invisible. This problem doesn't seem to occur on Windows, where the video and audio play as expected. Let's dive into the details and see what's going on.

Detailed Report

Engine Version

The game is running on version 1.0.1 of the engine. This is crucial info because knowing the engine version helps pinpoint if the issue is version-specific or a more general problem. When dealing with software bugs, the engine version serves as a foundational piece of the puzzle, allowing developers to trace the bug's origin and assess its impact on different builds. It's like having the blueprint of the machine you're trying to fix; without it, you're essentially groping in the dark.

Target Platform

The target platform experiencing the issue is Linux. This is a key piece of information because different operating systems handle multimedia playback in their own unique ways. What works seamlessly on Windows might stumble on Linux, and vice versa. Identifying the target platform narrows down the potential causes, steering our investigation towards Linux-specific libraries, drivers, or compatibility issues. It's akin to understanding the patient's medical history before diagnosing an ailment; the environment in which the bug manifests is as crucial as the bug itself.

Problem Explanation

Videos are invisible on Linux, but the audio plays fine. There are no console errors or crashes reported, making it a particularly tricky bug to catch. Imagine watching a movie where you can hear the dialogue but the screen is black – frustrating, right? This kind of issue, where functionality is partially working but not fully, can be quite puzzling. The absence of error messages adds another layer of complexity, as there are no breadcrumbs left behind to guide the troubleshooting process. It's like trying to solve a mystery without any clues, which is why a meticulous approach and a keen eye for detail are essential in such situations.

To illustrate the problem, a comparison was made between the Linux executable and the Windows executable running under Proton (Experimental). The same video files and script (from the wiki) were used in both cases. Here’s the script for reference:

import hxvlc.flixel.FlxVideo;
var video:FlxVideo = new FlxVideo();
video.onEndReached.add(function():Void
{
 video.dispose();

 FlxG.removeChild(video);
});
FlxG.addChildBelowMouse(video);

if (video.load(Paths.video("test")))
 new FlxTimer().start(0.001, (_) -> video.play());

On the left, the native Linux executable shows only audio, while on the right, the Windows executable (via Proton) plays both audio and video correctly. This side-by-side comparison clearly highlights that the issue is specific to the Linux build. It’s like having a control group in a scientific experiment; by comparing the results under different conditions, we can isolate the variable causing the problem. In this case, the variable is the operating system, pointing towards a potential incompatibility or missing component within the Linux environment.

Additional Context

The user provided a visual comparison demonstrating the issue. This is incredibly helpful because a picture is worth a thousand words, right? Seeing the problem firsthand often clarifies the issue more effectively than any written description could. The visual evidence confirms that the video playback is indeed failing on Linux while functioning correctly on Windows under Proton. This observation reinforces the notion that the bug is likely rooted in the Linux-specific handling of video playback, whether it's a missing codec, a driver issue, or a library conflict. It’s like having a witness statement in a court case; the visual proof corroborates the claim and strengthens the case for a focused investigation into the Linux side of things.

Potential Causes and Troubleshooting Steps

Alright guys, let’s brainstorm some potential causes and how we can tackle this bug. Here are a few ideas:

Codec Issues

One possibility is that the necessary video codecs aren't installed or aren't being accessed correctly on the Linux system. Codecs are like the secret decoder rings for video files – without them, your computer can't translate the file into something you can see and hear. Think of it like trying to read a book written in a language you don't understand; you need a translator (codec) to make sense of it. This is a common issue, especially across different operating systems, because they often come with different default codec sets. We need to ensure that the required codecs are present and that the game is configured to use them.

To troubleshoot this, we might need to check which codecs the video file uses and verify they are installed on the Linux system. Common codecs include H.264, VP9, and AV1. We could also try installing a comprehensive codec pack, like libavcodec-extra or similar, to cover a wide range of video formats. It's like equipping our computer with a universal translator, ensuring it can understand most video languages. This step is crucial because it addresses a fundamental requirement for video playback: having the right tools to decode the video stream.

Library Dependencies

Another suspect could be missing or incompatible library dependencies. Games, especially those dealing with multimedia, rely on various libraries to handle tasks like video decoding, audio playback, and rendering. These libraries are like the building blocks of a software application; if one block is missing or out of place, the whole structure can crumble. On Linux, these dependencies are managed differently than on Windows, which can lead to discrepancies in how the game runs on each platform.

We should investigate which libraries the game uses for video playback and ensure they are correctly installed and configured on the Linux system. Tools like ldd (List Dynamic Dependencies) can help us identify these libraries. It’s like using a detective's magnifying glass to examine the game's infrastructure and identify any missing components. Once we know the required libraries, we can use package managers like apt (on Debian/Ubuntu) or pacman (on Arch Linux) to install them. Ensuring all dependencies are in place is like making sure all the necessary ingredients are available before starting a recipe; without them, you can't expect the final dish to turn out right.

Graphics Drivers

Graphics drivers are the bridge between your operating system and your graphics card. If these drivers are outdated, corrupted, or not properly configured, they can cause all sorts of visual issues, including video playback problems. Think of your graphics driver as the interpreter between your software and your hardware; if the interpreter is speaking gibberish, the hardware won't know what to do. This is particularly relevant on Linux, where driver management can sometimes be more hands-on than on Windows.

To address this, we should ensure that the latest graphics drivers are installed for the user’s specific hardware. This might involve using proprietary drivers (like those from Nvidia or AMD) or open-source drivers (like Mesa). It’s like tuning your instrument before a performance; if your drivers are out of sync, the visual output will be off-key. We might also need to check for any known compatibility issues between the graphics drivers and the video playback libraries. Keeping drivers up-to-date and ensuring compatibility is a cornerstone of troubleshooting visual problems, as it ensures the hardware and software are communicating effectively.

hxvlc/FlxVideo Implementation

It’s also worth examining the hxvlc/FlxVideo implementation itself. This is the code that handles video playback within the game engine, so any bugs or inefficiencies in this code could be the culprit. Think of it as scrutinizing the recipe itself; if there's a typo or an incorrect instruction, the final product won't turn out as expected. The provided code snippet gives us a starting point, but we need to dive deeper into how FlxVideo interacts with the underlying video playback libraries on Linux.

We might need to review the source code for hxvlc and FlxVideo to identify any potential issues. This could involve looking for platform-specific code paths, checking how video files are loaded and decoded, and ensuring that resources are properly managed. It's like dissecting the engine to understand how each component works and interacts with others. We should also consider whether there are any known bugs or limitations in hxvlc that might be affecting video playback on Linux. Thoroughly inspecting the code is crucial for uncovering issues that might not be immediately apparent from the user's perspective.

Proton Compatibility (False Lead?)

While the video works under Proton, this doesn't necessarily mean the issue is a simple matter of missing dependencies. Proton essentially provides a compatibility layer that allows Windows games to run on Linux, but it doesn't always perfectly replicate the native environment. Think of Proton as a translator who can help two people communicate, but the translation might not always be flawless. The fact that the video plays correctly under Proton suggests that the core video playback libraries are likely present and functional on the system. However, there might be subtle differences in how these libraries are accessed or configured in the native Linux environment versus the Proton environment.

Therefore, while it's good to know that Proton works, we shouldn't rely solely on this as a solution. We still need to focus on identifying and fixing the root cause of the issue in the native Linux build. It’s like having a backup plan but still wanting to fix the primary system; while the backup can get you by in a pinch, it’s not a long-term solution. We need to address the underlying problem to ensure that the game runs smoothly on Linux without relying on compatibility layers.

Next Steps

Gather more information: We need to collect more details about the user’s system configuration, such as their Linux distribution, graphics card, and installed codecs. This is like gathering clues at a crime scene; the more information we have, the better our chances of solving the mystery. Specifics can help us narrow down the potential causes and identify any common patterns among users experiencing the issue. It’s like tailoring a diagnosis to a patient's individual symptoms; a one-size-fits-all approach rarely works in complex cases.
Reproduce the issue: The team should try to reproduce the bug on their own Linux systems. This is crucial for verifying the issue and testing potential fixes. Reproducing the bug is like recreating an experiment in a lab; it allows us to observe the problem firsthand and test different hypotheses. If we can consistently reproduce the issue, we can systematically try different solutions and measure their effectiveness. It’s a hands-on approach that ensures we're not just guessing but actively working towards a solution.
Test different video formats: We should try playing different video formats (e.g., MP4, AVI, WebM) to see if the issue is specific to a particular format. This is like running different tests on a sample to identify its properties; the results can provide valuable insights into the nature of the problem. If the issue only occurs with certain formats, it points towards a codec-related problem. If it affects all formats, it suggests a more fundamental issue with the video playback system. This systematic testing helps us narrow down the possibilities and focus our efforts on the most likely causes.
Examine console output: Even though the user didn’t report any console output, we should run the game from the terminal and check for any error messages or warnings. Sometimes, error messages can be hidden or overlooked, but they can provide valuable clues about what’s going wrong. It’s like listening closely for whispers in a noisy room; even faint signals can reveal important information. Console output can reveal issues like missing libraries, failed file loads, or errors in the video playback code. Examining the console is a standard troubleshooting step that often uncovers hidden problems, guiding us towards a more targeted solution.

Conclusion

The video playback issue on Linux is a tricky one, but by systematically investigating potential causes – from codec problems to graphics drivers and code implementation – we can hopefully nail down a solution. Thanks to the detailed bug report and the comparison provided, we have a solid foundation for troubleshooting. Let’s keep the conversation going and work together to squash this bug! Remember, every bug we fix makes the game better for everyone.

Additional Tips for Reporting Bugs

To help us resolve issues more efficiently in the future, here are a few additional tips for reporting bugs:

Be specific: The more details you provide, the better we can understand the issue. Include the engine version, target platform, steps to reproduce the bug, and any relevant error messages or screenshots.
Check for duplicates: Before submitting a bug report, search the existing issues to see if someone else has already reported the same problem. This helps avoid duplicate reports and keeps the issue tracker organized.
Provide a minimal reproduction: If possible, create a small, self-contained example that demonstrates the bug. This makes it easier for us to reproduce the issue and test fixes.
Stay responsive: Be available to answer questions and provide additional information if needed. This helps us work collaboratively to resolve the bug.

By following these tips, you can help us make the game engine even better!