How to Concatenate Videos with FFmpeg (Easy Tutorial)

Okay, here’s a comprehensive article on concatenating videos using FFmpeg, aiming for approximately 5000 words:

How to Concatenate Videos with FFmpeg (Easy Tutorial)

FFmpeg is a powerful, versatile, and free open-source command-line tool for handling multimedia files. One of its many capabilities is video concatenation – the process of joining multiple video clips together into a single, continuous video file. While the command-line interface might seem intimidating at first, concatenating videos with FFmpeg is surprisingly straightforward once you understand the basic principles. This tutorial will guide you through various methods, from the simplest to the more complex, covering different scenarios and potential issues.

Table of Contents

  1. Introduction to FFmpeg and Concatenation

    • What is FFmpeg?
    • What is Video Concatenation?
    • Why Use FFmpeg for Concatenation?
    • Installation (Brief – links to official documentation)
  2. Understanding Video Encoding and Compatibility

    • Video Codecs (H.264, VP9, AV1, etc.)
    • Audio Codecs (AAC, MP3, Opus, etc.)
    • Containers (MP4, MKV, AVI, etc.)
    • Resolution, Frame Rate, and Bitrate
    • The Importance of Matching Parameters
  3. Methods for Concatenating Videos with FFmpeg

    • Method 1: The concat Demuxer (Easiest for Identical Files)
      • Creating a mylist.txt file
      • The ffmpeg -f concat command
      • Example and Explanation
      • Limitations
    • Method 2: The concat Protocol (For Simple Concatenation)
      • Using the | (pipe) symbol
      • The ffmpeg -i "concat:input1.mp4|input2.mp4" command
      • Example and Explanation
      • Limitations
    • Method 3: The concat Filter (Most Flexible, Requires Re-encoding)
      • Understanding Filtergraphs
      • The ffmpeg -i input1.mp4 -i input2.mp4 -filter_complex command
      • Basic concat Filter Syntax: [0:v][0:a][1:v][1:a]concat=n=2:v=1:a=1[v][a]
      • Example and Explanation
      • Handling Different Resolutions and Aspect Ratios (Scaling and Padding)
      • Handling Different Frame Rates (Using fps filter)
      • Adding Transitions (Crossfades, etc. – Advanced)
      • Controlling Output Codec and Quality
  4. Troubleshooting Common Issues

    • “Unsafe file name” Error
    • “Invalid data found when processing input” Error
    • Audio Sync Issues
    • Codec Compatibility Problems
    • Different Resolutions/Frame Rates Leading to Errors
    • Output File Not Playing Correctly
  5. Advanced Techniques and Tips

    • Batch Concatenation (Using loops in Bash/PowerShell)
    • Concatenating Parts of Videos (Using -ss and -to or -t)
    • Adding Audio Tracks or Subtitles During Concatenation
    • Using Hardware Acceleration (NVIDIA NVENC, Intel Quick Sync, AMD VCE)
    • Understanding FFmpeg’s Output Messages
  6. Conclusion and Further Resources


1. Introduction to FFmpeg and Concatenation

  • What is FFmpeg?

    FFmpeg is a comprehensive suite of libraries and programs for handling multimedia data. It’s a command-line tool, meaning you interact with it by typing commands in a terminal (Command Prompt on Windows, Terminal on macOS and Linux). It’s incredibly powerful and can perform a vast array of tasks, including:

    • Video and Audio Conversion: Changing formats (e.g., MP4 to MKV), codecs (e.g., H.264 to VP9), and resolutions.
    • Video and Audio Editing: Cutting, trimming, concatenating, adding filters, and more.
    • Streaming: Encoding and broadcasting live video and audio.
    • Recording: Capturing screen or webcam input.
    • Multiplexing and Demultiplexing: Combining and separating video, audio, and subtitle streams.
  • What is Video Concatenation?

    Video concatenation is the process of joining two or more separate video files together, end-to-end, to create a single, longer video file. The resulting video plays the source videos sequentially, as if they were always one continuous clip.

  • Why Use FFmpeg for Concatenation?

    There are several reasons why FFmpeg is an excellent choice for video concatenation:

    • Free and Open-Source: FFmpeg is completely free to use and its source code is openly available.
    • Cross-Platform: It works on Windows, macOS, and Linux.
    • Highly Versatile: It supports a vast range of video and audio formats and codecs.
    • Powerful and Flexible: It offers fine-grained control over the concatenation process, allowing you to handle different resolutions, frame rates, and codecs.
    • Scriptable: You can automate concatenation tasks using scripts (e.g., Bash scripts on Linux/macOS or batch files on Windows).
    • No Watermarks: Unlike some free video editing software, FFmpeg doesn’t add watermarks to your output videos.
    • Command-Line Efficiency: For repetitive tasks or large numbers of files, the command-line interface can be significantly faster than a graphical user interface (GUI).
  • Installation (Brief – links to official documentation)

    Installing FFmpeg can vary slightly depending on your operating system. Here’s a brief overview, but always refer to the official FFmpeg documentation for the most up-to-date instructions:

    • Windows: The easiest way is to download pre-built binaries from a trusted source (like gyan.dev or BtbN). You’ll need to add the directory containing ffmpeg.exe to your system’s PATH environment variable so you can run FFmpeg from any command prompt. Detailed instructions can be found on the FFmpeg website and various online tutorials.
    • macOS: The recommended method is to use Homebrew, a package manager. Open Terminal and install Homebrew (instructions on the Homebrew website), then run brew install ffmpeg.
    • Linux: Most Linux distributions have FFmpeg in their package repositories. You can usually install it using your distribution’s package manager (e.g., apt-get install ffmpeg on Debian/Ubuntu, yum install ffmpeg on Fedora/CentOS, pacman -S ffmpeg on Arch Linux).

    Official FFmpeg Documentation: https://ffmpeg.org/download.html


2. Understanding Video Encoding and Compatibility

Before diving into the concatenation methods, it’s crucial to grasp some fundamental concepts about video encoding. This will help you understand why certain methods work best in specific situations and how to troubleshoot potential issues.

  • Video Codecs (H.264, VP9, AV1, etc.)

    A video codec (coder-decoder) is an algorithm that compresses and decompresses video data. Different codecs have different levels of compression efficiency, quality, and computational complexity. Some common video codecs include:

    • H.264 (AVC): The most widely used video codec, offering a good balance of quality and compression. Supported by almost all devices and software.
    • H.265 (HEVC): A more modern codec that offers significantly better compression than H.264 at the same quality, or better quality at the same file size. Requires more processing power.
    • VP9: An open-source codec developed by Google, often used for web streaming (e.g., YouTube). Offers good compression and quality.
    • AV1: A very new, open-source codec designed to be even more efficient than H.265 and VP9. Gaining popularity but still has limited hardware support.
    • MPEG-2: An older codec, still used in some contexts like DVDs and broadcast television.
    • ProRes: A family of codecs from Apple, used for professional video editing. Offers high quality and is designed for editing rather than final delivery.
    • DNxHD/DNxHR: Similar to ProRes, developed by Avid, also used for professional video editing.
  • Audio Codecs (AAC, MP3, Opus, etc.)

    Similar to video codecs, audio codecs compress and decompress audio data. Common audio codecs include:

    • AAC (Advanced Audio Coding): A widely used lossy audio codec, often used with H.264 video in MP4 files. Offers good quality at relatively low bitrates.
    • MP3 (MPEG-1 Audio Layer III): An older but still very popular lossy audio codec.
    • Opus: A modern, open-source codec designed for both speech and music, often used for web streaming and VoIP applications.
    • FLAC (Free Lossless Audio Codec): A lossless audio codec, meaning it compresses audio without any loss of quality. Results in larger file sizes.
    • AC-3 (Dolby Digital): A lossy audio codec commonly used in DVDs and Blu-ray discs.
  • Containers (MP4, MKV, AVI, etc.)

    A container format (also called a wrapper) is a file format that can hold multiple streams of data, typically video, audio, and subtitles. The container doesn’t define how the video or audio is encoded; that’s the job of the codec. Common container formats include:

    • MP4 (.mp4): A very popular and versatile container format, widely supported. Often used with H.264 video and AAC audio.
    • MKV (.mkv): A flexible and open-source container format that can hold almost any combination of video, audio, and subtitle codecs.
    • AVI (.avi): An older container format, still used but less flexible than MP4 or MKV.
    • MOV (.mov): A container format developed by Apple, often used with QuickTime.
    • WebM (.webm): An open-source container format designed for web use, typically used with VP9 or AV1 video and Opus audio.
  • Resolution, Frame Rate, and Bitrate

    • Resolution: The number of pixels in a video frame, expressed as width x height (e.g., 1920×1080, also known as 1080p). Higher resolution means more detail.
    • Frame Rate: The number of frames (still images) displayed per second (fps). Common frame rates include 24 fps (cinematic), 30 fps (common for TV and online video), and 60 fps (smoother motion).
    • Bitrate: The amount of data used to represent each second of video or audio, usually measured in kilobits per second (kbps) or megabits per second (Mbps). Higher bitrate generally means higher quality but also larger file size.
  • The Importance of Matching Parameters

    For seamless concatenation, it’s ideal for the video files you’re joining to have the same:

    • Video Codec: All files should use the same codec (e.g., H.264).
    • Audio Codec: All files should use the same audio codec (e.g., AAC).
    • Resolution: All files should have the same resolution (e.g., 1920×1080).
    • Frame Rate: All files should have the same frame rate (e.g., 30 fps).
    • Pixel Format: This is a more technical parameter, but usually, if the codec, resolution and framerate are the same, the pixel format will be too.

    If these parameters match, FFmpeg can often concatenate the videos without re-encoding, which is much faster and preserves the original quality. If the parameters don’t match, FFmpeg will need to re-encode the videos, which takes more time and can potentially result in some quality loss (although you can control the output quality).


3. Methods for Concatenating Videos with FFmpeg

FFmpeg provides several methods for concatenating videos, each with its own advantages and limitations.

  • Method 1: The concat Demuxer (Easiest for Identical Files)

    This is the simplest and fastest method, but it only works if all the video files you’re concatenating have the exact same encoding parameters (codec, resolution, frame rate, etc.). It works by treating a list of files as a single input stream.

    • Creating a mylist.txt file:

      You need to create a text file (e.g., mylist.txt) that lists the files you want to concatenate, one file per line, using the file directive. The paths to the files can be relative (to the current directory) or absolute.

      Example mylist.txt (assuming your video files are in the same directory):

      file 'input1.mp4'
      file 'input2.mp4'
      file 'input3.mp4'

      Important Notes about mylist.txt:

      • File Paths: Make sure the file paths are correct. If you have spaces in your file names, you must enclose the file name in single quotes (').
      • Line Endings: Use consistent line endings (Unix-style LF is preferred). If you’re creating the file on Windows, make sure your text editor is set to use LF line endings, or use a tool like dos2unix to convert them. Incorrect line endings can cause errors.
      • Escaping Special Characters: If your file names contain special characters like single quotes ('), backslashes (\), or others, you need to escape them. The simplest way is usually to use single quotes around the entire file name, and then replace any single quotes within the file name with '\''. For example, a file named My Video's File.mp4 would become:
        file 'My Video'\'s File.mp4'
      • Absolute vs. Relative Paths: You can use absolute paths (e.g., file 'C:\Videos\input1.mp4') or relative paths (e.g., file 'input1.mp4' if the file is in the same directory as mylist.txt).
    • The ffmpeg -f concat command:

      The basic command structure is:

      bash
      ffmpeg -f concat -safe 0 -i mylist.txt -c copy output.mp4

      • -f concat: Specifies the concat demuxer.
      • -safe 0: This option is essential when dealing with relative file paths or file names that might contain special characters. It disables the “safe” filename checking, which can prevent FFmpeg from reading the files correctly. Use this with caution, and only if you are sure your file paths are valid. If all of your files have simple names (no spaces or special characters) and are in the same directory as your mylist.txt file, you might be able to omit -safe 0. However, it’s generally best practice to include it.
      • -i mylist.txt: Specifies the input file list.
      • -c copy: This is the crucial part. It tells FFmpeg to copy the video and audio streams without re-encoding. This is what makes this method so fast and preserves the original quality. It only works if the input files have identical encoding parameters.
      • output.mp4: The name of the output file.
    • Example and Explanation:

      Let’s say you have three MP4 files (input1.mp4, input2.mp4, input3.mp4) in the same directory, all encoded with H.264, AAC audio, 1920×1080 resolution, and 30 fps. You create a mylist.txt file as shown above. Then you run the following command:

      bash
      ffmpeg -f concat -safe 0 -i mylist.txt -c copy output.mp4

      FFmpeg will read the file list, concatenate the video and audio streams without re-encoding, and create a new file named output.mp4 that contains all three videos joined together.

    • Limitations:

      • Strict Compatibility Requirement: This method only works if all the input files have the exact same encoding parameters (codec, resolution, frame rate, etc.). If there’s even a slight difference, it will fail.
      • No Re-encoding: While this is an advantage for speed and quality preservation, it also means you can’t use this method to change the output codec or other parameters.
  • Method 2: The concat Protocol (For Simple Concatenation)

    This method is slightly less strict than the concat demuxer but still works best with files that have similar encoding parameters. It uses the concat: protocol directly in the -i (input) option.

    • Using the | (pipe) symbol:

      The concat: protocol uses the pipe symbol (|) to separate the file names.

    • The ffmpeg -i "concat:input1.mp4|input2.mp4" command:

      The basic command structure is:

      bash
      ffmpeg -i "concat:input1.mp4|input2.mp4|input3.mp4" -c copy output.mp4

      • -i "concat:input1.mp4|input2.mp4|input3.mp4": Specifies the input files using the concat: protocol. The file names are separated by pipe symbols (|). Make sure there are no spaces around the pipe symbols.
      • -c copy: Attempts to copy the video and audio streams without re-encoding. This will work if the files are compatible, but it might fail if they have significant differences.
      • output.mp4: The name of the output file.
    • Example and Explanation:

      Using the same example files as before (input1.mp4, input2.mp4, input3.mp4), you would run:

      bash
      ffmpeg -i "concat:input1.mp4|input2.mp4|input3.mp4" -c copy output.mp4

      If the files are compatible, FFmpeg will concatenate them without re-encoding. If they are not fully compatible, FFmpeg might still attempt to concatenate them, but you might encounter issues like audio sync problems or errors.

    • Limitations:

      • Less Strict, but Still Sensitive to Differences: This method is more forgiving than the concat demuxer, but it still works best if the files have similar encoding parameters. Significant differences can lead to errors or problems with the output file.
      • Limited Scalability: For a large number of files, the command line can become very long and unwieldy. The concat demuxer with a file list is generally better for many files.
      • File Name Restrictions: You need to be careful with file names that contain pipe symbols (|) or other special characters. Escaping these characters can be tricky with this method. It’s often safer to rename files to avoid special characters when using this protocol.
  • Method 3: The concat Filter (Most Flexible, Requires Re-encoding)

    This is the most flexible method and can handle files with different encoding parameters, resolutions, and frame rates. However, it requires re-encoding the video, which takes more time and can potentially result in some quality loss (although you can control the output quality). This method uses FFmpeg’s powerful filtering system.

    • Understanding Filtergraphs:

      FFmpeg’s filtering system allows you to apply various transformations to video and audio streams. A filtergraph is a description of how these filters are connected. Filtergraphs can be simple (a single filter) or complex (many filters chained together).

    • The ffmpeg -i input1.mp4 -i input2.mp4 -filter_complex command:

      The basic command structure is:

      bash
      ffmpeg -i input1.mp4 -i input2.mp4 -filter_complex "[0:v][0:a][1:v][1:a]concat=n=2:v=1:a=1[v][a]" -map "[v]" -map "[a]" output.mp4

      • -i input1.mp4 -i input2.mp4: Specifies the input files. You can add more -i options for additional files.
      • -filter_complex: Indicates that you’re using a complex filtergraph.
      • "[0:v][0:a][1:v][1:a]concat=n=2:v=1:a=1[v][a]": This is the core of the concat filter. Let’s break it down:
        • [0:v]: Refers to the video stream of the first input file (input 0).
        • [0:a]: Refers to the audio stream of the first input file.
        • [1:v]: Refers to the video stream of the second input file (input 1).
        • [1:a]: Refers to the audio stream of the second input file.
        • concat=n=2:v=1:a=1: This is the concat filter itself.
          • n=2: Specifies the number of input segments (in this case, 2). You need to change this to the correct number of input files.
          • v=1: Indicates that there is one output video stream.
          • a=1: Indicates that there is one output audio stream.
        • [v][a]: These are the output labels for the video and audio streams. You can choose any names you like (e.g., [outv][outa]).
      • -map "[v]": Maps the output video stream labeled [v] to the output file.
      • -map "[a]": Maps the output audio stream labeled [a] to the output file.
      • output.mp4: The output file name.
    • Example and Explanation:

      bash
      ffmpeg -i input1.mp4 -i input2.mp4 -i input3.mp4 -filter_complex "[0:v][0:a][1:v][1:a][2:v][2:a]concat=n=3:v=1:a=1[v][a]" -map "[v]" -map "[a]" output.mp4

      This command concatenates three videos. Note how n=3 is used because there are three inputs. The input streams are listed in order: [0:v][0:a] for the first file, [1:v][1:a] for the second, and [2:v][2:a] for the third.

    • Handling Different Resolutions and Aspect Ratios (Scaling and Padding):

      If your input videos have different resolutions or aspect ratios, simply concatenating them will likely result in errors or a distorted output video. You need to use scaling and padding filters to make them consistent. Here’s a common approach:

      1. Choose a Target Resolution: Decide on the desired resolution for your output video (e.g., 1920×1080).
      2. Scale: Use the scale filter to resize each video to fit within the target resolution while maintaining its aspect ratio.
      3. Pad: Use the pad filter to add black bars (or another color) around the scaled video to fill the target resolution.

      Here’s an example that scales all videos to fit within a 1920×1080 frame, adding black bars as needed:

      bash
      ffmpeg -i input1.mp4 -i input2.mp4 -filter_complex \
      "[0:v]scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:(ow-iw)/2:(oh-ih)/2[v0]; \
      [1:v]scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:(ow-iw)/2:(oh-ih)/2[v1]; \
      [v0][0:a][v1][1:a]concat=n=2:v=1:a=1[v][a]" \
      -map "[v]" -map "[a]" output.mp4

      • scale=1920:1080:force_original_aspect_ratio=decrease: Scales the video to fit within 1920×1080. force_original_aspect_ratio=decrease ensures that the video is scaled down if necessary, maintaining its aspect ratio. If you used increase, it would scale up if necessary.
      • pad=1920:1080:(ow-iw)/2:(oh-ih)/2: Pads the video with black bars to make it exactly 1920×1080. (ow-iw)/2 and (oh-ih)/2 calculate the amount of padding needed on each side. ow and oh are output width and height, iw and ih are input width and height.
      • [v0], [v1]: Intermediate labels for the scaled and padded video streams.

      This example demonstrates a common and robust way to handle different resolutions. You can adjust the target resolution (1920×1080) as needed.

    • Handling Different Frame Rates (Using fps filter):

    If your videos have different frame rates, you should choose a target frame rate and use the fps filter to convert all videos to that frame rate. A common and safe approach is to choose the lowest frame rate among your input videos as the target, as this avoids potentially introducing stuttering by dropping frames.

    ```bash
    ffmpeg -i input1.mp4 -i input2.mp4 -filter_complex \
    "[0:v]fps=24[v0]; \
     [1:v]fps=24[v1]; \
     [v0][0:a][v1][1:a]concat=n=2:v=1:a=1[v][a]" \
    -map "[v]" -map "[a]" output.mp4
    ```
    
    *   `fps=24`:  Sets the frame rate to 24 fps.  Change this to your desired target frame rate.
    
    You can combine scaling, padding, and frame rate conversion in a single filtergraph:
    
    ```bash
    ffmpeg -i input1.mp4 -i input2.mp4 -filter_complex \
    "[0:v]fps=24,scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:(ow-iw)/2:(oh-ih)/2[v0]; \
     [1:v]fps=24,scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:(ow-iw)/2:(oh-ih)/2[v1]; \
     [v0][0:a][v1][1:a]concat=n=2:v=1:a=1[v][a]" \
    -map "[v]" -map "[a]" output.mp4
    ```
    
    • Adding Transitions (Crossfades, etc. – Advanced):

    FFmpeg supports various transition filters, including crossfades. This is a more advanced topic, but here’s a basic example of a crossfade between two videos:

    ```bash
    ffmpeg -i input1.mp4 -i input2.mp4 -filter_complex \
    "[0:v][1:v]xfade=transition=fade:duration=1:offset=2[v]; \
    [0:a][1:a]acrossfade=d=1[a]" \
    -map "[v]" -map "[a]" output.mp4
    ```
    
    *  `xfade=transition=fade:duration=1:offset=2`: This applies the `xfade` filter for a video crossfade.
        *   `transition=fade`: Specifies a fade transition.  FFmpeg has many other transition types (see the FFmpeg documentation).
        *   `duration=1`:  Sets the duration of the transition to 1 second.
        *   `offset=2`:  Specifies that the transition should start 2 seconds *before* the end of the first video. This is crucial; the offset should be equal to or greater than the duration for the transition to work as expected. The first video must be at least `offset + duration` seconds long.
    * `acrossfade=d=1`: Applies a 1-second audio crossfade using the `acrossfade` filter.
    
    This example assumes that `input1.mp4` is at least 3 seconds long (2 seconds for the offset + 1 second for the fade duration). You need to adjust the `offset` and `duration` parameters based on the length of your videos and the desired transition effect. This is more complex, and understanding the length and timing of your videos is key.
    
    • Controlling Output Codec and Quality:

    Since the concat filter requires re-encoding, you have full control over the output codec and quality. You can use options like -c:v (video codec), -c:a (audio codec), -b:v (video bitrate), and -b:a (audio bitrate) to specify these.

    Example:  Output to H.264 video with a target bitrate of 5 Mbps and AAC audio at 192 kbps:
    
    ```bash
    ffmpeg -i input1.mp4 -i input2.mp4 -filter_complex "[0:v][0:a][1:v][1:a]concat=n=2:v=1:a=1[v][a]" -map "[v]" -map "[a]" -c:v libx264 -b:v 5M -c:a aac -b:a 192k output.mp4
    ```
    
    *   `-c:v libx264`:  Uses the libx264 encoder (H.264).
    *   `-b:v 5M`:  Sets the video bitrate to 5 Mbps.
    *   `-c:a aac`:  Uses the AAC audio codec.
    *   `-b:a 192k`:  Sets the audio bitrate to 192 kbps.
    
    You can also use Constant Rate Factor (CRF) for H.264 encoding, which provides a more consistent quality level:
    
    ```bash
    ffmpeg -i input1.mp4 -i input2.mp4 -filter_complex "[0:v][0:a][1:v][1:a]concat=n=2:v=1:a=1[v][a]" -map "[v]" -map "[a]" -c:v libx264 -crf 23 -c:a aac -b:a 192k output.mp4
    ```
    
    *   `-crf 23`:  Sets the CRF value to 23.  Lower CRF values mean higher quality (and larger file size).  A range of 18-28 is generally recommended, with 23 being a good starting point.
    
    For H.265 (HEVC) encoding, you would use `libx265` and a similar `-crf` value.
    

4. Troubleshooting Common Issues

  • “Unsafe file name” Error:

    This error usually occurs when FFmpeg’s “safe” filename checking is enabled (by default) and it encounters a file name that it considers potentially unsafe (e.g., containing special characters or relative paths). The solution is to use the -safe 0 option with the concat demuxer:

    bash
    ffmpeg -f concat -safe 0 -i mylist.txt -c copy output.mp4

    Use this option with caution, and only if you are sure your file paths are valid.

  • “Invalid data found when processing input” Error:

    This error often indicates that the input files are not compatible for direct concatenation (using -c copy). It could be due to:

    • Different Codecs: The files might be using different video or audio codecs.
    • Different Resolutions/Frame Rates: The files might have different resolutions or frame rates.
    • Corrupted Files: One or more of the input files might be corrupted.
    • Incorrect File List: There might be an error in your mylist.txt file (wrong path, incorrect line endings, etc)

    The solution is usually to use the concat filter (Method 3), which re-encodes the video and allows you to handle these differences. Make sure to use scaling, padding, and the fps filter as needed to make the video streams consistent. If you suspect a corrupted file, try playing it individually to see if it works.

  • Audio Sync Issues:

    Audio sync problems can occur if the input files have different audio sample rates, frame rates, or if there are errors in the timestamps. This is more likely to happen with the concat protocol (Method 2).

    The best solution is to use the concat filter (Method 3) and re-encode the audio. FFmpeg will usually handle audio synchronization correctly during re-encoding. You might also want to explicitly specify the audio sample rate using the -ar option (e.g., -ar 48000 for 48 kHz).

  • Codec Compatibility Problems:

    If you’re trying to output to a specific codec (e.g., H.265) and you get an error, it might be because FFmpeg doesn’t have the necessary encoder installed. Make sure you have the required libraries (e.g., libx264 for H.264, libx265 for H.265). If you’re using a pre-built FFmpeg binary, it should usually include these common encoders. If you compiled FFmpeg yourself, you might need to recompile it with the appropriate libraries enabled.

  • Different Resolutions/Frame Rates Leading to Errors:

    As mentioned earlier, simply trying to concatenate files with different resolutions or frame rates using -c copy will usually result in errors. Use the concat filter (Method 3) with scaling, padding, and the fps filter to handle

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top