Creator media glossary
What is H.264 (AVC)?
Short answer
The most widely supported video codec, decoded natively by essentially every phone, browser and TV made in the last fifteen years.
Key takeaways
- H.264 (AVC, MPEG-4 Part 10) is the most compatible video codec: every phone, browser, editor and social platform handles it.
- Use the High profile, variable bitrate and AAC audio in MP4 for uploads.
- HEVC and AV1 reach the same quality in about half the size, but play on fewer devices.
- H.264 is patented, but internet video that is free to viewers pays no royalties.
H.264 (AVC) explained
H.264 is the default codec inside most MP4 and MOV files, and the safest choice for anything that needs to play everywhere without a compatibility question. It's less space-efficient than newer codecs like HEVC or AV1, but the universal hardware decoding support is usually worth more than the extra megabytes.
Every platform in this site's specs re-encodes uploaded video to H.264 (or its own internal codec) regardless of what you upload, which is part of why uploading an ultra-high-bitrate source rarely changes what viewers actually see.
How H.264 works
H.264 divides each frame into 16 × 16 pixel macroblocks, predicts each one from nearby pixels or from other frames, and stores only the difference. Its main tools:
- Three frame types: I-frames stored in full, P-frames that refer back, and B-frames that refer both ways. B-frames save the most space.
- Motion compensation down to quarter-pixel precision, with blocks as small as 4 × 4.
- An integer transform (4 × 4, plus 8 × 8 in the High profile) and quantization, controlled by the bitrate or CRF setting.
- CABAC or CAVLC entropy coding; CABAC is about 10-15% more efficient and is what YouTube recommends.
- An in-loop deblocking filter that smooths block edges, a big reason H.264 looked cleaner than MPEG-2 and MPEG-4 Part 2.
H.264 profiles and levels
A profile is a set of compression tools; a level caps resolution, frame rate and bitrate so a device knows in advance whether it can decode the stream.
| Profile | What it adds | Typical use |
|---|---|---|
| Constrained Baseline | No B-frames, CAVLC only; easy to decode | Video calls, WebRTC, very old phones |
| Main | B-frames and CABAC | Standard-definition TV, older streaming |
| High | 8 × 8 transform and quantization matrices | HD streaming, Blu-ray, uploads (YouTube recommends High) |
| High 10, High 4:2:2, High 4:4:4 | 10-bit and fuller color | Professional cameras and intermediates |
Common levels: 4.1 covers 1080p at 30 fps (Blu-ray uses it), 4.2 covers 1080p at 60 fps, 5.1 covers 4K at 30 fps and 5.2 covers 4K at 60 fps.
History and licensing
H.264 was developed by the Joint Video Team of ITU-T and ISO/IEC MPEG and first approved in 2003, which is why it has two names: H.264 at the ITU and MPEG-4 Part 10 (AVC) at ISO. It went on to carry Blu-ray, HD broadcasting, YouTube, video calls and nearly every phone camera.
H.264 is a patented standard. Device and software makers pay royalties through a patent pool administered by Via Licensing Alliance (formerly MPEG LA), but internet video that is free to viewers has been royalty-free since 2010. Cisco distributes a free, royalty-paid H.264 decoder (OpenH264) that browsers such as Firefox use for video calls.
H.264 (AVC) support by platform
| Platform | Status | Best container |
|---|---|---|
| TikTok | Recommended | MP4 |
| Instagram Reels | Recommended | MP4 |
| Instagram Feed | Recommended | MP4 |
| Instagram Stories | Recommended | MP4 |
| YouTube Shorts | Recommended | MP4 |
| YouTube (long-form) | Recommended | MP4 |
| Recommended | MP4 | |
| X (Twitter) | Recommended | MP4 |
| Facebook Reels | Recommended | MP4 |
| Facebook Feed | Recommended | MP4 |
| Recommended | MP4 | |
| Snapchat | Recommended | MP4 |
| Snapchat Spotlight | Recommended | MP4 |
| Snapchat Story | Recommended | MP4 |
| Spotify Canvas | Recommended | MP4 |
| Threads | Recommended | MP4 |
From each platform's published upload specs; follow a platform for its full codec matrix and sources.
Recommended H.264 export settings for social video
| Setting | 1080p at 24-30 fps | 1080p at 50-60 fps | 4K at 24-30 fps |
|---|---|---|---|
| Profile | High | High | High |
| Level | 4.1 or 4.2 | 4.2 | 5.1 |
| Bitrate (VBR target) | 8 Mbps | 12 Mbps | 35-45 Mbps |
| Keyframes | Closed GOP, half the frame rate | Closed GOP, half the frame rate | Closed GOP, half the frame rate |
| Color | 4:2:0, 8-bit, BT.709 | 4:2:0, 8-bit, BT.709 | 4:2:0, 8-bit, BT.709 |
| Audio | AAC-LC, 48 kHz, stereo | AAC-LC, 48 kHz, stereo | AAC-LC, 48 kHz, stereo |
| Container | MP4, fast start | MP4, fast start | MP4, fast start |
Bitrates and GOP from YouTube's recommended upload encoding settings; the Instagram API caps video at 25 Mbps, so these fit both.
Where H.264 is used
- Uploads and streaming: YouTube, social apps and most websites accept or deliver H.264.
- Blu-ray Discs and HD television broadcasts.
- Video calls: WebRTC requires browsers to support H.264 (and VP8).
- Phones, action cameras, drones and security cameras, often as the "most compatible" option.
- Hardware encoders in almost every GPU and phone chip, including NVIDIA NVENC, Intel Quick Sync, AMD AMF and Apple VideoToolbox.
H.264 vs H.265 vs AV1
| H.264 (AVC) | H.265 (HEVC) | AV1 | |
|---|---|---|---|
| Approved | 2003 | 2013 | 2018 |
| Bitrate for the same quality | Baseline | About 50% lower | About 30% lower than HEVC |
| Playback support | Everywhere | Most devices since about 2017; browsers vary | Newer devices with hardware decode |
| Encoding speed | Fast | Slower | Slowest in software |
| Licensing | Royalties, free for free internet video | Several patent pools | Royalty-free |
| Best for uploads | Yes, documented everywhere | Where the platform lists it | Rarely documented |
Savings are rough figures from the standards bodies and AOMedia; real results depend on the encoder and the content.
Advantages and drawbacks of H.264
Advantages
- Plays on practically every phone, browser, TV and editor
- Hardware encoding and decoding on almost every device, so it is fast and battery friendly
- The format every major social platform documents for uploads
- Mature encoders such as x264 give excellent quality per bit
Drawbacks
- Needs roughly twice the bitrate of HEVC or AV1 for the same quality
- Not designed for HDR; 10-bit High 10 has limited playback support
- Patented, so some open-source projects avoid shipping an encoder
- Large files at 4K compared with newer codecs
How to export or convert to H.264
- In an editor, choose H.264 (sometimes "MP4" or "Match source - High bitrate") with the High profile, variable bitrate and AAC audio.
- On iPhone, Settings > Camera > Formats > Most Compatible records H.264 instead of HEVC.
- With FFmpeg:
ffmpeg -i input.mov -c:v libx264 -crf 20 -preset slow -c:a aac -b:a 192k -movflags +faststart output.mp4 - Or use our free converters and compressor, which write H.264 MP4 in your browser and keep the file on your device.
Free tools:Video compressorMOV to MP4WebM to MP4
Frequently asked questions
What is H.264?
H.264, also called AVC (Advanced Video Coding) or MPEG-4 Part 10, is a video compression standard. It is the most widely supported video codec: phones, browsers, editors and every major social platform play it.
Is H.264 the same as MP4?
No. H.264 is the codec that compresses the picture; MP4 is the container file that holds the video, the audio and metadata. Most MP4 files carry H.264 video, which is why the two are often confused. H.264 can also sit inside MOV or MKV.
What H.264 settings does YouTube recommend?
YouTube recommends H.264, progressive scan, High Profile, 2 consecutive B-frames, a closed GOP of half the frame rate, CABAC, variable bitrate and 4:2:0 chroma subsampling, in an MP4 with the moov atom at the front.
H.264 or H.265 for uploads?
H.264 is the safe default: every platform in the table below documents it. H.265 (HEVC) gives similar quality at a lower bitrate and is accepted by YouTube and the Instagram API, but is not documented everywhere.
Is H.264 good for 4K?
It works, at Level 5.1 or 5.2, but needs a high bitrate (YouTube recommends 35-45 Mbps for 4K at 24-30 fps). HEVC or AV1 reach the same quality in much smaller files if your target supports them.
What is x264?
A free, open-source software encoder that produces H.264 video. It is built into FFmpeg, HandBrake and OBS and is known for very good quality per bit.
Is H.264 lossless?
In normal use it is lossy. The High 4:4:4 Predictive profile has a lossless mode, but files are huge and few players support it.
Let Koldflux pick the settings
Koldflux chooses the codec, container and bitrate for each platform when it exports.
Free tools that use this
Sources and how we checked
- YouTube Help: Recommended upload encoding settings (checked 2026-10-05)
- MDN: Web video codec guide (checked 2026-10-05)
- Instagram API: IG User Media (reel, story and video specifications) (checked 2026-10-05)
- ITU-T Recommendation H.264: Advanced video coding for generic audiovisual services (checked 2026-10-06)
- Via LA: AVC/H.264 patent pool (checked 2026-10-06)
Reviewed October 6, 2026 by the Koldflux team. Definitions follow the specifications and platform documentation linked above; platform tables come from the same registry the Koldflux tools use.