Understanding Video Codec Differences: HEVC vs H.264 for Mobile Devices

You've probably seen "HEVC" and "H.264" mentioned in camera settings, video info panels, or storage tips. But what do these terms actually mean, and why should you care?

A video codec is the algorithm that compresses raw video into a manageable file size. Without compression, a single minute of 4K video would be about 12 GB. Codecs reduce that to hundreds of megabytes—but not all codecs are equally efficient. The difference between HEVC and H.264 is roughly a 2x factor in file size at the same visual quality.

This guide explains the practical differences between these two codecs in terms that matter to iPhone users: file sizes, quality, battery impact, compatibility, and what to do with each type of video in your library.

The Simple Explanation

Think of codecs as languages for storing video. H.264 is an older language that uses more words to describe a scene. HEVC is a newer language that describes the same scene with fewer words—same meaning, less space.

H.264 was the universal standard for over a decade. Every device made since 2005 can play H.264 video. It's reliable, well-understood, and compatible with everything.

HEVC (H.265) is the successor, designed to handle 4K and beyond. It produces files roughly half the size of H.264 at the same quality. Since 2017, it's been the default recording format on iPhones.

Both codecs produce .mp4 or .mov files that look identical on screen. The difference is entirely in how efficiently they store the data.

Side-by-Side File Size Comparison

The pattern holds across all resolutions and frame rates: HEVC is consistently ~50% smaller.

Quality: Is HEVC Better or Just Smaller?

Both. At the same file size, HEVC produces better visual quality because it allocates bits more intelligently. At the same visual quality, HEVC uses half the bits. You can think of it as a win-win: smaller files AND better quality per byte.

The technical reasons:

• Larger analysis blocks (64x64 vs 16x16 pixels) handle uniform areas more efficiently
• More prediction directions (35 vs 9) represent gradients and textures better
• Better motion handling compresses camera movement and object motion more effectively
• Advanced filtering reduces visible artifacts at lower bitrates

In practical terms: if you watch an HEVC video and an H.264 video of the same content side by side on your iPhone, you won't see a difference. But the HEVC file takes half the storage.

Battery and Performance

During recording

On modern iPhones (8 and later), both codecs use dedicated hardware encoders. Recording in HEVC uses roughly the same battery as H.264—the hardware handles both efficiently. There's no reason to avoid HEVC recording for battery concerns.

During playback

Both codecs have hardware decoders on all modern devices. Playback is equally smooth and battery-efficient for both.

During compression (post-recording)

Converting H.264 to HEVC uses the hardware encoder and processes at roughly 30 seconds per minute of 4K. Battery impact is minimal when plugged in. Software-based compression (used by some third-party apps) would be much slower and battery-intensive, but hardware-accelerated tools like HEVCut avoid this problem.

Compatibility in 2026

When HEVC launched in 2017, compatibility was a legitimate concern. Many older devices couldn't play HEVC files. In 2026, this is largely resolved:

HEVC plays natively on:

• All iPhones from iPhone 6 (2014) onward (playback)
• All iPhones from iPhone 8 (2017) onward (recording + playback)
• All iPads from 2017 onward
• All Macs with Apple silicon
• Windows 10/11 (HEVC extension, free since 2023)
• Android devices from 2018 onward
• All major streaming platforms
• All modern smart TVs

H.264 plays on: Literally everything. Any device that plays video supports H.264.

Where H.264 still matters:

• Very old PCs or budget devices
• Some enterprise and legacy systems
• Web embedding where maximum compatibility is critical
• Email attachments sent to unknown recipients

Apple handles the compatibility gap automatically: when you share an HEVC video via AirDrop, email, or Messages with a device that doesn't support HEVC, iOS converts it to H.264 transparently.

How to Know Which Codec Your Videos Use

Check individual videos

Open a video in Photos, tap the info (i) button, and look for codec information in the technical details. "HEVC" means it's using the efficient codec. "H.264" or no codec label means it's using the older format.

Check your camera setting

Settings > Camera > Formats. "High Efficiency" = HEVC. "Most Compatible" = H.264. If it's set to Most Compatible, every video you record is twice as large as it needs to be.

Scan your entire library

HEVCut scans your library and identifies the codec of every video, showing you exactly how many H.264 files you have and how much space you'd save by converting them.

What to Do with Your H.264 Videos

If you have a mix of HEVC and H.264 videos (most iPhone users do), the H.264 files are the prime candidates for compression.

Common sources of H.264 videos:

• Recordings from iPhones before 2017
• Videos received via WhatsApp, Telegram, email
• Screen recordings from older iOS versions
• Videos transferred from Android or cameras
• Downloaded content from the web

The fix: Convert them to HEVC. This is a one-time operation that cuts their size by ~50% with no visible quality change. Use HEVCut for batch processing with metadata preservation.

FAQ

Is HEVC the same as H.265?

Yes. HEVC (High Efficiency Video Coding) and H.265 are two names for the same standard. Apple calls it "High Efficiency" in iPhone settings.

Should I ever record in H.264 on purpose?

Only if you need maximum compatibility with very old devices. In 2026, this scenario is rare. HEVC is supported on virtually all modern hardware. For normal use, High Efficiency (HEVC) is strictly better.

Can I convert HEVC back to H.264?

Yes, but it would make the file larger with no quality benefit. Going from HEVC to H.264 is going backwards—more space for the same (or slightly lower) quality. The useful direction is H.264 → HEVC.

Do social media platforms support HEVC?

Yes. Instagram, TikTok, YouTube, Facebook, and Twitter/X all accept HEVC uploads. The platforms re-encode your video on their servers regardless of the input codec, so the upload format doesn't affect the final result viewers see.

Does converting H.264 to HEVC reduce quality?

The quality difference is imperceptible in practice. HEVC uses a fundamentally more efficient compression algorithm, so it represents the same visual content in fewer bits. At the bitrates used by iPhone compression tools, the quality is indistinguishable from the H.264 original.