Audio stream synchronization

Oct 13, 2025 by wbrum.org 112 views

MPC Script Source + MPC Video Renderer: Uncovering the Mystery of the Green Vertical Line

In the world of video playback, even the smallest details can make a significant difference. One such detail is the presence of a green vertical line that appears when using the MPC Script Source with the MPC Video Renderer in MPC-HC and MPC-BE. This issue has puzzled many users, and in this article, we will delve into the possible causes and solutions to this problem.

The green vertical line is a peculiar issue that only manifests when using the MPC Script Source with the MPC Video Renderer. This combination is unique to MPC-HC and MPC-BE, and other renderers such as EVR do not exhibit this behavior. The issue is not specific to a particular file or format, but rather a result of the interaction between the script source and the video renderer.

The Script Source: A Key Player

The MPC Script Source is a powerful tool that allows users to manipulate video and audio streams using a scripting language. The script is used to create a new audio stream that is then synchronized with the video stream. In the case of the provided script, the audio stream is created using the LWLibavAudioSource function, and the video stream is created using the LWLibavVideoSource function.

a=LWLibavAudioSource("test.mp4")
AudioDub(LWLibavVideoSource("test.mp4",fpsnum=50), a)

This script creates a new audio stream from the "test.mp4" file and then dubs it onto a new video stream with a frame rate of 50 FPS.

The Video Renderer: A Critical Component

The MPC Video Renderer is responsible for rendering the video stream to the screen. It takes the video stream as input and produces a rendered video output. In the case of the MPC Script Source, the video renderer is responsible for rendering the video stream that has been modified by the script.

The Green Vertical Line: A Result of the Interaction

The green vertical line is a result of the interaction between the script source and the video renderer. When the script source creates a new audio stream and dubs it onto the video stream, it creates a temporary audio stream that is not synchronized with the video stream. This temporary audio stream is then rendered by the video renderer, resulting in a green vertical line.

There are several possible causes for the green vertical line, including:

Inconsistent frame rates: The script source creates a new video stream with a frame rate of 50 FPS, while the original video stream has a different frame rate. This inconsistency can cause the video renderer to produce a green vertical line.
Audio stream synchronization: The script source creates a new audio stream that is not synchronized with the video stream. This can cause the video renderer to produce a green vertical line.
Video renderer settings: The video renderer settings may be causing the green vertical line. For example, if the video renderer is set to render the video stream with a specific aspect ratio, it may produce a green vertical line.

To solve the issue, users can try the following:

Check the frame rates: Ensure that the frame rates of the original video stream and the new video stream created by the script source are consistent.
Synchronize the audio stream: Ensure that the audio stream created by the script source is synchronized with the video stream.
Adjust the video renderer settings: Adjust the video renderer settings to ensure that the video stream is rendered correctly.

The green vertical line that appears when using the MPC Script Source with the MPC Video Renderer in MPC-HC and MPC-BE is a result of the interaction between the script source and the video renderer. By understanding the possible causes and solutions to this issue, users can troubleshoot and resolve the problem. In this article, we have explored the possible causes and solutions to this issue, and provided a step-by-step guide to resolving the problem.

For more information on the MPC Script Source and the MPC Video Renderer, please refer to the following resources:

MPC-HC documentation: The MPC-HC documentation provides detailed information on the MPC Script Source and the MPC Video Renderer.
MPC-BE documentation: The MPC-BE documentation provides detailed information on the MPC Script Source and the MPC Video Renderer.
LWLibav documentation: The LWLibav documentation provides detailed information on the LWLibavAudioSource and LWLibavVideoSource functions.

The source file for the script is available at the following location:

https://files.fm/u/upa2ygcb2s

The script used to create the green vertical line is as follows:

a=LWLibavAudioSource("test.mp4")
AudioDub(LWLibavVideoSource("test.mp4",fpsnum=50), a)
```<br/>
**MPC Script Source + MPC Video Renderer: Q&A**

**Introduction**
===============

In our previous article, we explored the issue of the green vertical line that appears when using the MPC Script Source with the MPC Video Renderer in MPC-HC and MPC-BE. In this article, we will answer some of the most frequently asked questions about this issue.

**Q: What is the MPC Script Source?**
--------------------------------------

A: The MPC Script Source is a powerful tool that allows users to manipulate video and audio streams using a scripting language. It is a part of the MPC-HC and MPC-BE media players.

**Q: What is the MPC Video Renderer?**
--------------------------------------

A: The MPC Video Renderer is responsible for rendering the video stream to the screen. It takes the video stream as input and produces a rendered video output.

**Q: Why does the green vertical line appear when using the MPC Script Source with the MPC Video Renderer?**
-----------------------------------------------------------------------------------------

A: The green vertical line appears when the script source creates a new audio stream that is not synchronized with the video stream. This can cause the video renderer to produce a green vertical line.

**Q: How can I troubleshoot the issue?**
-----------------------------------------

A: To troubleshoot the issue, you can try the following:

* Check the frame rates of the original video stream and the new video stream created by the script source.
* Synchronize the audio stream created by the script source with the video stream.
* Adjust the video renderer settings to ensure that the video stream is rendered correctly.

**Q: Can I use other renderers to avoid the green vertical line?**
---------------------------------------------------------

A: Yes, you can use other renderers such as EVR to avoid the green vertical line. However, the MPC Video Renderer is a powerful and flexible renderer that offers many features and options.

**Q: Is the green vertical line a bug in the MPC Script Source or the MPC Video Renderer?**
--------------------------------------------------------------------------------------

A: The green vertical line is not a bug in the MPC Script Source or the MPC Video Renderer. It is a result of the interaction between the script source and the video renderer.

**Q: Can I report the issue to the developers?**
------------------------------------------------

A: Yes, you can report the issue to the developers of the MPC-HC and MPC-BE media players. They may be able to provide additional information or assistance.

**Q: Are there any workarounds for the issue?**
------------------------------------------------

A: Yes, there are several workarounds for the issue. You can try the following:

* Use a different script source or video renderer.
* Adjust the video renderer settings to avoid the green vertical line.
* Use a different media player that does not exhibit the issue.

**Conclusion**
==============

The green vertical line that appears when using the MPC Script Source with the MPC Video Renderer in MPC-HC and MPC-BE is a result of the interaction between the script source and the video renderer. By understanding the possible causes and solutions to this issue, users can troubleshoot and resolve the problem. In this article, we have answered some of the most frequently asked questions about this issue.

**Additional Resources**
=====================

For more information on the MPC Script Source and the MPC Video Renderer, please refer to the following resources:

* **MPC-HC documentation**: The MPC-HC documentation provides detailed information on the MPC Script Source and the MPC Video Renderer.
* **MPC-BE documentation**: The MPC-BE documentation provides detailed information on the MPC Script Source and the MPC Video Renderer.
* **LWLibav documentation**: The LWLibav documentation provides detailed information on the LWLibavAudioSource and LWLibavVideoSource functions.

**Source File**
=============

The source file for the script is available at the following location:

https://files.fm/u/upa2ygcb2s

**Script**
=========

The script used to create the green vertical line is as follows:

```python
a=LWLibavAudioSource("test.mp4")
AudioDub(LWLibavVideoSource("test.mp4",fpsnum=50), a)