Concatenating MP4 Files: Overcoming Parsing Packet Header Errors with FFmpeg's concatlist

Concatenating MP4 Files using FFmpeg's concat list method

If you have multiple MP4 files that you want to concatenate into a single file, you can use the FFmpeg concat list method. This method allows you to specify the files you want to concatenate in a text file, and then use the concat demuxer to combine them into a single MP4 file.

Creating a concat list file

The first step in concatenating MP4 files using the concat list method is to create a text file that lists the files you want to concatenate. This text file should contain the following format:

Each line of the text file should start with the word "file" followed by the path to the MP4 file you want to concatenate. Make sure to include the single quotes around the file path.

Using the concat demuxer

Once you have created the concat list file, you can use the FFmpeg concat demuxer to combine the MP4 files into a single file. The command to do this is as follows:

Replace with the name of your concat list file, and output.mp4 with the name you want to give to the output file. The "-c copy" option tells FFmpeg to copy the video and audio streams from the input files to the output file without re-encoding them, which can save a lot of time.

Handling parsing packet header errors

When concatenating MP4 files using the concat demuxer, you may encounter parsing packet header errors. This can happen if the MP4 files have different codecs, bitrates, or frame sizes. To overcome this issue, you can use the ffmpeg-concat filter.

The ffmpeg-concat filter allows you to concatenate video and audio streams with different codecs, bitrates, and frame sizes. To use the filter, you need to modify the FFmpeg command as follows:

This command concatenates three MP4 files (file1.mp4, file2.mp4, and file3.mp4) using the concat filter. The "-filter\_complex" option specifies the filter to use, and the "[0:v][0:a][1:v][1:a][2:v][2:a]" argument specifies the input streams to use. The "concat" filter concatenates the input streams into a single output stream, and the "n=3:v=1:a=1" argument specifies the number of inputs, the number of video streams, and the number of audio streams, respectively.

• To concatenate MP4 files using FFmpeg's concat list method, create a text file that lists the files you want to concatenate in the following format:
• file '/path/to/file1.mp4' file '/path/to/file2.mp4' file '/path/to/file3.mp4'
• Use the following FFmpeg command to concatenate the MP4 files:
• ffmpeg -f concat -i -c copy output.mp4
• To handle parsing packet header errors, use the ffmpeg-concat filter:
• ffmpeg -i file1.mp4 -i file2.mp4 -i file3.mp4 -filter\_complex "[0:v][0:a][1:v][1:a][2:v][2:a]concat=n=3:v=1:a=1[outv][outa]" -map "[outv]" -map "[outa]" output.mp4

References

• FFmpeg Formats - Concat
• FFmpeg Wiki - Concatenate
• Super User - FFmpeg concat protocol vs concat filter