MKV File Format: How it Works - MKV vs MP4

Learn about the Matroska Multimedia Container (MKV) format, its history, features and comparison with MP4. Explore the strengths and weaknesses of MKV and MP4 and learn when to choose MKV over MP4.

What is MKV Format? (Matroska Video File)

The MKV file format, also known as Matroska Multimedia Container, is a flexible and open standard multimedia container format. It is designed to hold numerous video, audio, picture, or subtitle tracks in a single file, making it perfect for storing movies or TV shows with multiple audio tracks, subtitles, or alternative languages.

MKV files use an open standard and are not limited to any specific codec, allowing for greater flexibility during playback. They can contain virtually any type of media encoded using a variety of codecs, including popular ones like H.264 for video and AAC for audio, as well as less common or proprietary codecs.

The Matroska format, often abbreviated as MKV, is governed by the non-profit organization Association Loi 1901. It is licensed under GNU L-GPL for personal use. MKV is also available for commercial purposes under a BSD license, providing free parsing, analysis, and playback libraries.

The file extensions associated with the Matroska format include:

• “.mkv” for video files (which may also contain subtitles or audio).
• “.mk3d” for stereoscopic video files.
• “.mka” for audio-only files.
• “.mks” for subtitle-only files.

MKV Short History and Goals

The Matroska multimedia container format, often abbreviated as MKV, originated in 2002 as an open and flexible standard for storing various types of multimedia content. It was developed by a group of enthusiasts seeking to address limitations in existing container formats like AVI and MP4. Matroska aimed to offer a modern, efficient, and extensible solution capable of accommodating a wide range of audio, video, subtitle, and metadata tracks within a single file.

One of the primary goals of Matroska was to provide a format that could store high-quality multimedia content without compromising on flexibility or compatibility. Unlike some proprietary formats, Matroska was designed to be open, meaning its specifications were freely available for anyone to use and implement. This openness fostered innovation and encouraged widespread adoption across different platforms and software applications.

Another key objective of Matroska was to support a diverse array of codecs and technologies, ensuring compatibility with both popular and emerging audio and video compression methods. This flexibility allowed content creators and consumers to use the codecs that best suited their needs without being constrained by the limitations of the container format itself.

MKV Key Features

We are highlighting the 12 key features of the MKV file format here, and we will provide a brief description of each as we proceed.

1. Open Standard
2. Container Format
3. Flexible and Extensible
4. Lossless Compression
5. Subtitle and Audio Track Support
6. Chapter Support
7. Metadata
8. Streaming Support
9. Cross-Platform Compatibility
10. High Definition and 4K Support
11. Subtitle Formatting Options
12. Adaptive Streaming

Open Standard

MKV is an open standard, meaning that its specifications are freely available and can be implemented by anyone without restrictions. This has contributed to its widespread adoption and support across various platforms and software applications.

Container Format

MKV is a container format, which means it can contain different types of multimedia data (such as video, audio, subtitles, and metadata) within a single file. This makes it convenient for organizing and distributing multimedia content without the need for separate files for each component.

Flexible and Extensible

MKV is highly flexible and extensible, allowing for the inclusion of virtually any type of multimedia content and supporting a wide range of codecs and encoding methods. This flexibility makes it suitable for a variety of use cases, from storing high-definition video to archiving multimedia collections.

Lossless Compression

MKV supports both lossy and lossless compression methods for audio and video data. This means that content can be stored in MKV files without significant loss of quality, making it suitable for archival purposes or for preserving the original quality of media content.

Subtitle and Audio Track Support

MKV files can include multiple audio tracks and subtitle streams, allowing users to select their preferred language or audio format during playback. This is particularly useful for international audiences or for multimedia content with multiple language options.

Chapter Support

MKV supports chapter markers, allowing users to navigate easily through long-form multimedia content such as movies or TV shows. Chapters can be used to divide content into meaningful segments, making it easier to navigate and manage large files.

Metadata

MKV files can store metadata information such as title, author, and copyright details, providing additional context and organization for multimedia content. This metadata can be useful for cataloging and searching through large collections of media files.

Streaming Support

MKV files can be streamed over the internet, enabling users to watch multimedia content in real-time without the need to download the entire file first. This makes MKV a suitable format for online video streaming platforms and services.

Cross-Platform Compatibility

MKV files are supported across multiple operating systems, including Windows, macOS, Linux, and various mobile platforms (Android, iOS). This cross-platform compatibility ensures that MKV files can be played back on a wide range of devices and software applications without compatibility issues.

High Definition and 4K Support

MKV supports high-definition (HD) and ultra-high-definition (UHD) resolutions, including 720p, 1080p, and even 4K formats. This makes it suitable for storing and distributing high-quality video content, including movies, TV shows, and home videos.

Subtitle Formatting Options

MKV supports a wide range of subtitle formats and allows for advanced formatting options such as font styles, colors, and positioning. This flexibility enables users to customize the appearance of subtitles to suit their preferences or to meet accessibility requirements.

Adaptive Streaming

MKV files can be used for adaptive streaming, a technique where the quality of the video stream is dynamically adjusted based on the available bandwidth and device capabilities. This allows for smooth playback of multimedia content across different network conditions and devices.

MKV vs. MP4: 5 Major Differences

Both MKV and MP4 are popular formats. Here, we will discuss the five major differences between these two formats.

1. Container Structure:

   • MKV (Matroska Multimedia Container): MKV is a flexible and open-standard container format that can hold multiple types of multimedia content, including video, audio, subtitles, and metadata. It allows for unlimited tracks and is highly customizable.
   • MP4 (MPEG-4 Part 14): MP4 is a standardized multimedia container format defined by the MPEG group. It is widely used for storing digital audio and video streams, as well as other data like subtitles and still images. MP4 has a more rigid structure compared to MKV.

2. Codec Support:

   • MKV: MKV is codec-agnostic, meaning it can support a wide range of audio and video codecs, including popular ones like H.264, H.265, VP9, AAC, and FLAC, among others.
   • MP4: MP4 also supports a variety of audio and video codecs, but it has a more limited selection compared to MKV. Common codecs for MP4 include H.264, AAC, and MPEG-4.

3. Features:

   • MKV: MKV offers advanced features such as support for multiple audio and subtitle tracks, chapter markers, extensive metadata capabilities, and error recovery mechanisms.
   • MP4: MP4 supports basic features like multiple audio and subtitle tracks, but it may not offer the same level of customization and flexibility as MKV.

4. Popularity and Compatibility:

   • MKV: MKV is popular among enthusiasts and content creators who value its flexibility and open-standard nature. It is widely supported by many media players and devices, but some older or less common devices may have limited compatibility.
   • MP4: MP4 is one of the most widely used container formats and is supported by virtually all media players, devices, and streaming platforms. It is the preferred format for many online video services and digital distribution platforms due to its widespread compatibility.

5. File Size and Compression:

   • Both MKV and MP4 offer efficient compression without significant loss of quality, but the choice of codec and compression settings can impact the file size and quality of the resulting media content.

Differences between MKV and MP4

The following table provides an overview of the differences between MKV and MP4 formats.

Pros and Cons of MKV and MP4

Both MKV and MP4 formats have their strengths and weaknesses, the choice between them often depends on factors such as specific use case, desired features, compatibility requirements, and personal preferences.

MKV Format: Pros and Cons

Pros:

1. Flexibility: MKV is a highly flexible and open-standard container format that can store a wide range of multimedia content, including video, audio, subtitles, and metadata.
2. Codec Agnostic: MKV supports a diverse range of audio and video codecs, giving users the freedom to choose the codecs that best suit their needs.
3. Advanced Features: MKV offers advanced features such as support for multiple audio and subtitle tracks, chapter markers, extensive metadata capabilities, and error recovery mechanisms.
4. Quality Preservation: MKV files maintain high-quality multimedia content even after compression, making them suitable for storing high-definition and even 4K video formats.
5. Customization: Users have greater control over their viewing experience with MKV, thanks to features like customizable subtitles, audio tracks, and chapter markers.

Cons:

1. Compatibility: While MKV is widely supported by many media players and devices, some older or less common devices may have limited compatibility with MKV files.
2. File Size: Depending on the codecs and compression settings used, MKV files may have larger file sizes compared to other formats, which could impact storage and transfer.

MP4 Format: Pros and Cons

Pros:

1. Widespread Compatibility: MP4 is one of the most widely supported container formats, compatible with virtually all media players, devices, and streaming platforms.
2. Efficient Compression: MP4 offers efficient compression without significant loss of quality, making it suitable for storing multimedia content while minimizing file size.
3. Standardization: MP4 is a standardized container format defined by the MPEG group, ensuring consistency and interoperability across different systems and software.
4. Preferred Format: MP4 is the preferred format for many online video services and digital distribution platforms, making it ideal for sharing and streaming multimedia content.

Cons:

1. Limited Features: MP4 may lack some advanced features found in other container formats, such as support for multiple audio and subtitle tracks or extensive metadata capabilities.
2. Less Flexibility: Compared to more flexible formats like MKV, MP4 has a more rigid structure and may offer fewer customization options for users.

When you should choose MKV over MP4?

You should choose MKV format when you require a high degree of flexibility and versatility in storing multimedia content. MKV excels in accommodating various codecs, multiple audio tracks, subtitles, and metadata within a single file, making it ideal for situations where you need to store diverse media elements with different language options or additional features. Additionally, if you value openness and prefer a format with freely available specifications that encourage innovation and compatibility across different platforms and software applications, MKV is the preferred choice.

When you should choose MP4 over MKV?

Choose the MP4 format when you prioritize broad compatibility, efficient compression, and seamless playback across various devices and platforms. MP4 is widely supported by a multitude of devices, software, and online streaming services, making it the go-to choice for sharing and streaming video content. Its efficient compression algorithms strike a balance between file size and video quality, ensuring that your videos maintain high quality while minimizing storage requirements.

Further Reading

• What is MP4 File Format and Everything You Need to Know