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# MPSImageFeatureChannelFormat

Encodes the representation of a single channel within an image.

```
enum MPSImageFeatureChannelFormat
```

## Overview

A pixel in an [`MPSImage`](/documentation/MetalPerformanceShaders/MPSImage) object may have many channels in it, sometimes many more than 4, that exceed the limit of what a <doc://com.apple.documentation/documentation/Metal/MTLPixelFormat> value can encode. The storage format for a single channel within a pixel can be given by the [`MPSImageFeatureChannelFormat`](/documentation/MetalPerformanceShaders/MPSImageFeatureChannelFormat) type. The number of channels is defined by the [`featureChannels`](/documentation/MetalPerformanceShaders/MPSImage/featureChannels) property of an [`MPSImage`](/documentation/MetalPerformanceShaders/MPSImage) object. The size of the pixel is the size of the channel format multiplied by the number of feature channels. No padding is allowed, except to round out to a full byte.

## Topics

### Constants

[`MPSImageFeatureChannelFormat.none`](/documentation/MetalPerformanceShaders/MPSImageFeatureChannelFormat/none)

[`MPSImageFeatureChannelFormat.unorm8`](/documentation/MetalPerformanceShaders/MPSImageFeatureChannelFormat/unorm8)

`uint8_t` type with value `[0,255]` and encoding `[0,1.0]`.

[`MPSImageFeatureChannelFormat.unorm16`](/documentation/MetalPerformanceShaders/MPSImageFeatureChannelFormat/unorm16)

`uint16_t` type with value `[0,65535]` and encoding `[0,1.0]`.

[`MPSImageFeatureChannelFormat.float16`](/documentation/MetalPerformanceShaders/MPSImageFeatureChannelFormat/float16)

IEEE-754 16-bit floating-point type (half precision). Representable normal range is `+-[2^-14, 65504], 0, INF, NaN`. 11 bits of precision + exponent.

[`MPSImageFeatureChannelFormat.float32`](/documentation/MetalPerformanceShaders/MPSImageFeatureChannelFormat/float32)

IEEE-754 32-bit floating-point type (single precision, standard `float` type in C). 24 bits of precision + exponent.

[`MPSImageFeatureChannelFormat_reserved0`](/documentation/MetalPerformanceShaders/MPSImageFeatureChannelFormat/MPSImageFeatureChannelFormat_reserved0)


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