The decision of which video format to use for streaming can significantly impact the overall quality, performance, and accessibility of your content. Among the most common formats for video streaming are FLV (Flash Video) and MP4 (MPEG-4 Part 14). Both formats offer different advantages depending on the intended use, audience, and platform. Choosing the right one is essential for ensuring that your video streams efficiently while delivering high-quality playback.
In this article, we’ll explore the differences between FLV and MP4, provide real-world examples, and help you decide which format is the best fit for your streaming needs.
What is FLV?
FLV (Flash Video) is a container format developed by Macromedia (later acquired by Adobe) for delivering video content online, primarily through Adobe Flash Player. In its early days, FLV dominated platforms like YouTube and Hulu due to its small file size and ability to be streamed over low-bandwidth connections.
However, as of December 2020, Adobe discontinued Flash Player, leading to a rapid decline in FLV usage. With the rise of HTML5 and other modern streaming technologies, FLV is now considered outdated, though it may still exist in certain legacy systems.
What is MP4?
MP4 (MPEG-4 Part 14) is a multimedia container format designed to store video, audio, subtitles, and images. It is the most widely supported format across platforms, devices, and operating systems. MP4 is based on the ISO/IEC standard, which has helped it become one of the most popular video formats for both streaming and downloading.
Thanks to advanced compression algorithms (such as H.264 and H.265), MP4 provides high-quality video with relatively small file sizes, making it the preferred format for streaming on platforms like YouTube, Facebook, and Netflix.
Key differences between FLV and MP4
Let’s break down the most important factors when comparing FLV and MP4.
1. File size and compression
FLV: FLV files are relatively small, making them ideal for low-bandwidth connections. This was a key reason for their popularity in the early 2000s when internet speeds were slower.
MP4: MP4 files also offer efficient compression, but with superior quality at smaller sizes compared to FLV. H.264 (and the newer H.265) codecs allow MP4 to deliver high-quality video while keeping file sizes manageable, making it a better option for HD and 4K content.
Example:
In a 5-minute 1080p video, an FLV file might be 60 MB, whereas an MP4 of the same quality could be around 45 MB due to better compression algorithms. This reduction in file size without compromising quality makes MP4 more efficient.
2. Compatibility and support
FLV: FLV was once universally supported due to the prevalence of Flash Player. However, since Adobe officially ended Flash support, most modern browsers and mobile devices no longer natively play FLV files. It is now only relevant for older systems or specialized applications.
MP4: MP4 is one of the most universally compatible formats available today. It plays seamlessly on mobile devices, desktops, tablets, and even gaming consoles. MP4 is fully supported by modern web browsers through HTML5, making it the go-to format for video streaming platforms.
Example:
YouTube initially relied on FLV but switched to MP4 to improve compatibility with mobile devices and modern browsers. As of today, all major streaming platforms (including Twitch and Vimeo) use MP4.
3. Video quality
FLV: While FLV delivers decent quality, especially for low-resolution videos, its compression sacrifices video clarity, making it less suitable for HD or 4K streaming. This was acceptable in the early days of the internet but has since become a limitation.
MP4: MP4 is known for delivering superior video quality across all resolutions. With support for 1080p, 4K, and even 8K, MP4 can maintain high-definition video without the need for large file sizes or heavy bandwidth. The H.264 codec ensures high-quality streaming, making it the preferred format for professional content creators.
Example:
A video streamed in 720p FLV might appear pixelated compared to the same video in MP4, which would offer sharper images and smoother playback.
4. Streaming efficiency
FLV: FLV was designed to stream well over low-bandwidth connections, which was ideal for users with slower internet speeds. While this was a significant advantage in the past, FLV’s outdated technology does not handle adaptive streaming well, meaning it can’t adjust to varying internet speeds dynamically.
MP4: MP4 is more efficient for both low and high-bandwidth streaming. It is compatible with adaptive streaming protocols like HLS (HTTP Live Streaming) and DASH (Dynamic Adaptive Streaming over HTTP). This allows the video to automatically adjust its quality based on the viewer’s internet speed, ensuring smoother playback.
Example:
Streaming platforms like Netflix and Amazon Prime use MP4 with adaptive streaming to ensure that viewers can watch high-quality video, regardless of fluctuating internet speeds.
5. Security and encryption
FLV: FLV offers little in terms of security. Since it relied on Flash Player, it was vulnerable to security risks like malware and hacking. Today, without active support for Flash, FLV files are at even greater risk.
MP4: MP4 supports DRM (Digital Rights Management) and advanced encryption protocols, making it a secure format for streaming services. This is crucial for premium content providers who need to protect their videos from unauthorized access or piracy.
Example:
Services like HBO Max and Disney+ use MP4 with DRM to protect their exclusive content from being illegally copied or redistributed.
6. Future viability
FLV: With the discontinuation of Flash, FLV is essentially obsolete. Its usage is confined to legacy systems and older platforms, and it is no longer a viable format for modern streaming needs.
MP4: MP4 is a future-proof format. Its continued updates, broad compatibility, and support for the latest codecs ensure that it will remain a dominant format for video streaming in the foreseeable future.
Example:
MP4 continues to evolve with new compression standards like H.265 (HEVC), which improves video quality even further while reducing bandwidth consumption. This makes MP4 ideal for future streaming platforms.
In this graph:
File size: The MP4 indicates its superior performance in achieving smaller file sizes with better quality compared to FLV.
Video quality: MP4's higher bar demonstrates its ability to deliver sharp quality even in HD and 4K, while FLV's lower bar shows its struggle with high resolutions.
Compatibility: The significant difference in bar heights reflects MP4's broad compatibility across modern devices and platforms, contrasting with FLV's declining usage after 2020.
Streaming efficiency: MP4's maximum score here represents its excellence in adaptive streaming (HLS/DASH), ensuring smoother playback, while FLV's minimum score indicates its lack of adaptability.
Summarizing the key differences
Criteria
FLV (Flash video)
MP4 (MPEG-4 Part 14)
File size
Relatively small, ideal for low bandwidth
Efficient compression, smaller size with better quality
Video quality
Lower quality, especially at higher resolutions
High-quality video, supports HD, 4K, and higher
Compatibility
Limited support after Flash's end, not supported by modern browsers
Universally compatible across platforms and devices
Streaming efficiency
Optimized for low bandwidth, but not adaptive
Supports adaptive streaming, adjusts to bandwidth
Security
Vulnerable, lacks built-in security features
Supports DRM and encryption for secure streaming
Future viability
Obsolete after Flash discontinuation
Future-proof, continues to evolve with new codecs
Use cases
Legacy systems, low-bandwidth environments
Modern streaming, high-quality video, secure content delivery
Case study: YouTube's transition from FLV to MP4
YouTube began shifting from the FLV (Flash video) format to MP4 (H.264) format in March 2008, when it added support for 480p videos encoded using the H.264/MPEG-4 AVC codec. This marked the start of YouTube's switchover to MP4 as its default video format.
The overall shift from FLV (Flash Video) to MP4 on YouTube was part of a broader trend in the late 2000s, driven by changes in both technology and user demand.
Key details:
YouTube's initial use of FLV:
When YouTube first launched in 2005, it primarily used the FLV format for streaming videos. This was because Adobe Flash was widely supported across browsers, making it the de facto standard for online video streaming. FLV allowed for embedding videos directly into websites and provided relatively good quality at smaller file sizes.
The Start of the transition:
In early 2009, YouTube began offering videos in MP4 format (with H.264 encoding) in addition to FLV. This change started with videos available in 720p and 1080p resolutions, where MP4 became the default format due to its superior compression and quality compared to FLV. The shift was largely influenced by the increasing demand for higher-quality HD content.
H.264 encoding in MP4 allowed for smaller file sizes without compromising video quality, making it more efficient for YouTube's massive data storage and bandwidth usage.
Advantages of MP4 over FLV:
Better Compression: MP4 (with H.264) provided better video compression, which meant that YouTube could deliver higher-quality videos with less bandwidth usage.
Cross-Device Compatibility: As mobile usage grew rapidly around 2009-2010, FLV's dependence on Flash became a drawback. MP4 offered much better compatibility with mobile devices, which increasingly supported HTML5 video playback without the need for Flash.
HTML5 Support: The rise of HTML5 as a new standard for web video meant a move away from Flash-based formats like FLV. MP4 was one of the key formats supported by HTML5 video, which led to YouTube’s further adoption of the format.
Complete move to MP4 and HTML5:
By 2015, YouTube fully transitioned to HTML5 video, essentially abandoning Flash entirely, meaning MP4 became the standard format for all videos. This final step was a part of a broader industry shift away from Flash due to its security vulnerabilities and performance issues on modern platforms.
Why the change happened:
Mobile growth: With smartphones rapidly becoming more popular in the late 2000s, the need for a format that could play seamlessly across various platforms became essential.
Browser compatibility: Flash’s security issues and the introduction of HTML5 provided a strong incentive to switch to MP4, which was more secure, faster, and less resource intensive.
Higher quality streaming: As YouTube began offering HD and later 4K content, MP4’s more advanced compression technology was necessary to stream videos in higher resolutions without excessive data usage.
Which format should you choose for streaming?
Based on the differences highlighted, here’s when you should choose FLV or MP4:
When to use FLV
Legacy systems: If you are working with older systems or platforms that require Flash-based video, FLV may be your only option.
Low-bandwidth streaming: For extremely low-bandwidth environments where quality is less important, FLV’s smaller file sizes could be a benefit. However, alternative formats like WebM or lower-quality MP4 are often better options.
When to use MP4
Modern streaming: MP4 is the best choice for nearly all modern streaming environments due to its wide compatibility and superior quality.
High-quality content: If you plan to stream in HD, 4K, or higher resolutions, MP4 offers the best balance of quality, file size, and bandwidth efficiency.
Security needs: For platforms requiring DRM protection, MP4 is the clear choice.
Bottomline
While FLV had its time as a dominant video format, it’s clear that MP4 has taken the lead in modern streaming with its superior quality, compatibility, and adaptability. MP4’s efficiency in handling high-resolution content and its seamless performance across platforms makes it a clear choice for today's streaming needs. FLV, though still in use for legacy systems, has largely become obsolete in the era of adaptive streaming and high-definition expectations.
However, navigating the complexities of video formats isn’t just about choosing the right one—it’s about ensuring your content performs optimally across diverse environments. This is where FastPix can help. With its ability to handle wide variety of video formats, you can optimize videos to provide better streaming experiences. FastPix helps developers and platforms to maximize video quality and compatibility without any hassle. Every single part of FastPix is built to help developers move faster throughout any video-centric project.
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