Welcome back! In our previous lesson, we explored how to use FFmpeg and its ffprobe component to analyze media files within Java applications. Today, we will focus on processing large audio and video files by splitting them into smaller, manageable segments using FFmpeg from Java. This approach is essential for efficiently handling large files, ensuring that subsequent processing tasks — such as transcription or analysis — can be performed smoothly and reliably. By leveraging FFmpeg's capabilities from Java, you will be able to automate the splitting of large media files into smaller chunks, making your applications more robust and scalable.

Many multimedia processing tasks, such as transcription or analysis, require files to be below a certain size threshold for optimal performance and compatibility with various services. When dealing with large audio or video files, it becomes necessary to divide them into smaller segments that can be processed sequentially. In this lesson, we will use FFmpeg to split large files into chunks of a specified maximum size, all from within a Java program. This ensures that your Java applications can efficiently handle large media files, maintain content quality, and avoid issues related to file size limitations.

Before splitting a media file, we need to determine its total duration. This information allows us to calculate how to divide the file into appropriately sized chunks. In Java, we can use the ProcessBuilder class to execute the ffprobe command and capture its output.

Explanation:
This Java method executes the ffprobe command to retrieve the duration of a media file. It reads the output from the process and parses the duration as a double. If the duration cannot be determined, it returns -1.

Splitting large media files can take time, and FFmpeg will produce logs as it processes the file. To monitor progress in real time, we can stream FFmpeg's output to the Java console using standard input/output handling.

Explanation:
This helper method runs a command (such as FFmpeg) and streams its output to the console in real time. It uses Java's ProcessBuilder and BufferedReader to read and print each line of output as it becomes available.

Now let's create the utility methods that will help us split media files. We'll start with helper methods for extracting file extensions and processing individual chunks.

Explanation:
The extractChunk method handles the creation of a single media chunk from the original file. It calculates the start time based on the chunk index and duration, creates a temporary file with the appropriate extension, constructs the FFmpeg command to extract the specific time segment, and executes the command while displaying progress information.

Why Use Temporary Files:
We write the output to temporary files using Files.createTempFile() for several important reasons:

Now we'll implement the main method that orchestrates the entire splitting process by calculating chunk parameters and coordinating the extraction of individual segments.

Code Explanation:

1. Initialize Variables:

   • The method retrieves the media file's duration using MediaUtils.getMediaDuration. We need this to calculate how to divide the timeline into appropriately sized chunks.
   • The file size is obtained to calculate the appropriate chunk duration for the specified chunk size in megabytes.

2. Calculate Chunks:

To test the splitting functionality, you can invoke the method as follows:

If your sample_video.mp4 file is around 2MB, splitting it into 1MB chunks will produce two separate files, each containing a segment of the original video. The output will display the progress and the paths to the generated chunk files.

Congratulations! You have learned how to split large media files into smaller, manageable chunks using FFmpeg from Java. By integrating FFmpeg commands into your Java applications, you can efficiently process large audio and video files, reduce memory overhead, and enable parallel or sequential processing for improved performance — all while maintaining the quality of your content. You are now equipped to handle large-scale multimedia tasks with confidence and precision in your Java projects!