Convert Video Formats
MP4 vs. MKV, h.264 vs. h.265, Container vs. Codec — demystifying the format universe. Plus: How to improve video quality.
The old AVI video doesn't play on the new smart TV. The recording from the media library is in the wrong format. The cell phone video is unnecessarily large for YouTube. Format conversion is the solution — if you know what you're doing. Here, we show you what containers and codecs are, which formats make sense when, and how to convert effectively.
📋 Content of this page
Container vs. Codec — The Most Important Difference
This is where most people get confused: Container and Codec are two different things, but are often conflated.
What is a Container?
The container is the "wrapper" of a video file — it determines everything that's inside the file: video track, audio tracks, subtitles, metadata, chapters. Identifiable by the file extension: .mp4, .mkv, .avi, .mov, .webm.
What is a Codec?
The codec is the compression method within the container. It determines how the video is encoded — how efficiently it stores data, how well the quality is preserved, how much processing power is needed for playback. Examples: H.264, H.265 (HEVC), VP9, AV1.
📦 Container = Packaging, Codec = Content
An everyday comparison: An .mp4 file is like a pizza box. What's inside — Margherita, Salami, Hawaiian — corresponds to the codec. Different pizzas fit into the same box. Different codecs fit into the same container.
Why it Matters
If your video doesn't play on a device: Is it due to the container or the codec? Both have different solutions.
- Container not recognized: "Repack" the file into another container — usually lossless and takes seconds
- Codec not supported: Video must be re-encoded — takes longer, can reduce quality
The Most Important Container Formats
| Format | Strengths | Weaknesses | When is it useful? |
|---|---|---|---|
| MP4 | Universally compatible, compact, fast | Less flexible with subtitles, limited tracks | Universal format — playable everywhere |
| MKV | Very flexible: many audio tracks, subtitles, chapters | Not supported everywhere (old TVs!) | Movies/series with multi-language support, home media library |
| AVI | Classic, almost universally playable | Outdated, less efficient, poor codec selection | Only for very old software/hardware |
| MOV | Apple standard, high quality | Sometimes issues outside the Apple ecosystem | Apple devices, video editing with Final Cut |
| WebM | Specifically for the web, good compression, royalty-free | Limited support outside browsers | Web videos, YouTube, small files |
| WMV | Windows standard (was) | Outdated, should not be used anymore | Only for legacy applications |
Which Format for What Purpose?
- Universal format: MP4 with H.264 — works everywhere, good quality, compact
- Movies & series at home: MKV with H.265 — smallest files, all languages included
- Web/Social Media: MP4 with H.264, alternatively WebM
- Apple devices: MP4 with H.265 (HEVC) — preferred by Apple
- Maximum quality for editing: MOV with ProRes or DNxHD (Professional)
Understanding Codecs
With codecs, it's primarily about one question: How much quality for how much file size and how much processing power?
The Most Important Video Codecs
| Codec | Efficiency | Hardware Acceleration | Practical Use |
|---|---|---|---|
| H.264 / AVC | Standard for 15+ years | Everywhere | Universal codec, from smartphone to TV |
| H.265 / HEVC | ~50% smaller than H.264 at the same quality | Devices from approx. 2017 | 4K videos, home collection |
| VP9 | Similar to H.265, but royalty-free | Browsers, some TVs | YouTube uses VP9 |
| AV1 | Another ~30% more efficient than H.265 | Only new devices (from 2020+) | Future, not yet universal |
| MPEG-2 | Outdated, inefficient | Standard on DVDs | Only for DVD compatibility |
Audio Codecs (Frequently Needed)
- AAC — Standard for MP4, good quality at small size
- MP3 — Universal codec, a bit older, playable everywhere
- FLAC — lossless, larger files, for audiophiles
- AC-3 / Dolby Digital — DVD/Blu-ray standard, 5.1 surround
- DTS / DTS-HD — Blu-ray surround, highest quality
- Opus — most modern audio codec, perfect for web/streaming
💡 Practical Recommendation: For your own collection, future-proof for 2026: MP4 container with H.265 video + AAC audio. Alternatively, MKV container with H.265 + Opus, if you want maximum efficiency and don't need to play on old devices.
Improving Video Quality
Besides conversion, there are other tools: improving existing videos instead of just changing the format.
What You Can Achieve with Conversion
- Reduce file size — old H.264 videos to H.265 = half the size
- Adjust resolution — scale down 4K video for mobile playback
- Optimize bitrate — lower too high bitrate, too low cannot be increased (more on that below)
- Consolidate multiple audio tracks — for MKV files
- Embed subtitles — externally as a file or burn directly into the video
What You Cannot Achieve with Conversion
- Better quality than the original — conversion can never add information that wasn't there
- Retrieve lost details — motion blur, pixelation, compression artifacts remain
- More FPS — if the original has 30 FPS, conversion cannot make it 60 FPS (except with AI interpolation)
Tips for Good Conversion
- Don't lower bitrate too much — for 1080p video, at least 4-6 MBit/s should remain
- Don't forget audio — AAC at 128 kbit/s is stereo standard, 192 kbit/s for audiophiles
- Consider target device — 720p for mobile, 1080p or 4K for TV
- Keep the original until you are sure the conversion was successful
🟡 MyFormatConverter — Universal & Easy
MyFormatConverter converts between all common formats — MP4, MKV, AVI, MOV, WebM, WMV — and adjusts codecs as needed. Perfect choice if you need an old AVI video for your new smart TV, want to optimize a phone video for YouTube, or standardize a collection of different formats.
Practical: Pre-configured profiles for devices (iPhone, Android, Smart TV, PS5/Xbox) — you select the target device, the rest runs automatically.
For Old/Poor Quality Recordings: AI Upscaling
If you want to get the most out of old recordings: AI upscaling can actually "invent" details that plausibly fit the image. Tools like Topaz Video AI transform 480p recordings into usable 1080p or even 4K. But: This is its own software category, not classic conversion.
📊 Conversion Rule of Thumb
Conversion changes the format and can optimize size. Genuine quality improvement is only possible with AI-based tools — and even there: miracles don't happen. A totally pixelated video won't become a Hollywood blockbuster.
Convert videos universally
MyFormatConverter converts between all formats and automatically adapts videos to your target device. Fast, easy, without hassle.
🎞️ MyFormatConverter