Скачать или смотреть Fixing the Unplayable MP4 Problem with OpenCV's VideoWriter

Learn how to resolve the issue of unplayable MP4 files generated with OpenCV's VideoWriter by implementing essential changes to your code for proper video format and color encoding.
---
This video is based on the question https://stackoverflow.com/q/77063341/ asked by the user 'Dom' ( https://stackoverflow.com/u/13677296/ ) and on the answer https://stackoverflow.com/a/77069129/ provided by the user 'Dom' ( https://stackoverflow.com/u/13677296/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: File Unplayable when using VideoWriter with OpenCV

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Troubleshooting Unplayable MP4 Files in OpenCV

Using OpenCV's VideoWriter can make capturing video frames a breeze; however, some users encounter issues when trying to play back the saved MP4 files. If you've run into an error message stating, "This file isn't playable," you may be feeling frustrated and confused, especially as a beginner. Fear not! In this guide, we'll walk you through the steps to effectively resolve this issue.

Understanding the Problem

When you use OpenCV's VideoWriter to capture and save video frames, the resulting file may sometimes not be playable due to various reasons, such as:

Unsupported file format

Incorrect file extension

Corrupted video file

In this guide, we will look at specific adjustments to your code that can help you save your MP4 videos so they play back without issues.

Adjusting Your Code

To successfully solve the problem with the unplayable MP4 file, we'll need to make a few key changes to your existing code. Let’s break down those adjustments step by step.

Step 1: Update VideoWriter's FourCC Code

The FourCC code is essential for defining the codec used for encoding your video. In your original code, you used a tuple to specify the FourCC code. Instead, we’ll simplify it by using a string representation:

Original Code

[[See Video to Reveal this Text or Code Snippet]]

Revised Code

[[See Video to Reveal this Text or Code Snippet]]

This change will ensure that the codec is initialized correctly for MP4 file creation.

Step 2: Set the Correct Resolution

It’s crucial that the resolution specified in your VideoWriter matches the actual dimensions of the video frames being captured. If you are capturing a window with a resolution of 1600x900, the VideoWriter should also be set to that resolution.

Original Code

[[See Video to Reveal this Text or Code Snippet]]

Revised Code

[[See Video to Reveal this Text or Code Snippet]]

Step 3: Handle Color Conversion

OpenCV captures images in BGR format by default, while some codecs (including those for MP4) expect images in RGB format. To address this, you will need to convert the image properly before writing it to the video file.

Original Return Statement

[[See Video to Reveal this Text or Code Snippet]]

Revised Return Statement

[[See Video to Reveal this Text or Code Snippet]]

Final Complete Code Example

Bringing all of these changes together, here is a snippet of how your main.py would now look:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By making these adjustments to your code, you should now be able to save playable MP4 files without encountering issues. Remember to always ensure your VideoWriter settings match the screen dimensions and handle color formats appropriately. This is vital to creating videos that play back smoothly. Happy coding!