---
title: AVVideoH264EntropyModeKey
framework: avfoundation
role: symbol
role_heading: Global Variable
path: avfoundation/avvideoh264entropymodekey
---

# AVVideoH264EntropyModeKey

The entropy encoding mode for H.264 compression.

## Declaration

```swift
let AVVideoH264EntropyModeKey: String
```

## Discussion

Discussion This property controls whether an H.264 encoder uses AVVideoH264EntropyModeCAVLC or AVVideoH264EntropyModeCABAC. CABAC generally gives better compression at the expense of higher computational overhead. important: The default value is encoder-specific and may change depending on other encoder settings. Set a value for this property only if the requested profile and level support it. Setting an incompatible value may result in encoding errors or a noncompliant output stream.

## See Also

### Entropy mode

- [AVVideoH264EntropyModeCABAC](avfoundation/avvideoh264entropymodecabac.md)
- [AVVideoH264EntropyModeCAVLC](avfoundation/avvideoh264entropymodecavlc.md)