Howto merge two avi files using ffmpeg?

To merge two AVI files using FFmpeg, follow these steps:

First, ensure FFmpeg is installed on your computer. Verify the installation by entering ffmpeg -version in the command line.

Next, use FFmpeg's concat protocol to merge files. There are two primary methods: using the concat filter or the concat protocol. Below, I'll provide examples for both approaches.

Using concat filter

This method works best when the video files share similar encoding and formats.

1. Create a list file containing the paths to the video files to be merged, for example inputs.txt, with the following content:

   shell
   file '/path/to/first.avi'
   file '/path/to/second.avi'

   Replace /path/to/first.avi and /path/to/second.avi with your actual file paths.

2. Run the following command to merge the videos:

   sh
   ffmpeg -f concat -safe 0 -i inputs.txt -c copy output.avi

   Here, -f concat specifies the concat format, -safe 0 enables absolute paths, -i inputs.txt defines the input file list, -c copy copies video and audio streams without re-encoding, and output.avi is the merged output filename.

Using concat protocol

This method is simpler but requires all video files to have identical encoding, resolution, and frame rate.

1. Use the concat protocol directly in the command line with the following command:

   sh
   ffmpeg -i "concat:/path/to/first.avi|/path/to/second.avi" -c copy output.avi

   Here, concat:/path/to/first.avi|/path/to/second.avi specifies the files to merge, separated by the pipe |. -c copy similarly instructs FFmpeg to copy streams without re-encoding.

In the above command, the -c copy parameter ensures FFmpeg avoids re-encoding video and audio streams when possible, providing faster processing and preserving original quality. However, if encoding or format differences exist, remove -c copy to allow FFmpeg to re-encode for compatibility.

Finally, note that when merging videos, ensure all files are compatible in video encoding, resolution, and frame rate; otherwise, the merged video may not play correctly. If necessary, convert the video files first to ensure consistent encoding and format.