---
title: CMBlockBuffer
framework: coremedia
role: symbol
role_heading: Class
path: coremedia/cmblockbuffer
---

# CMBlockBuffer

A reference to a block buffer instance.

## Declaration

```swift
class CMBlockBuffer
```

## Topics

### Modifying a Block Buffer

- [append(length:allocator:range:flags:)](coremedia/cmblockbuffer/append(length:allocator:range:flags:).md)
- [append(buffer:allocator:flags:)](coremedia/cmblockbuffer/append(buffer:allocator:flags:)-28keu.md)
- [append(buffer:allocator:flags:)](coremedia/cmblockbuffer/append(buffer:allocator:flags:)-8fws8.md)
- [append(length:allocator:deallocator:range:flags:)](coremedia/cmblockbuffer/append(length:allocator:deallocator:range:flags:).md)
- [append(buffer:deallocator:flags:)](coremedia/cmblockbuffer/append(buffer:deallocator:flags:)-3bfef.md)
- [append(buffer:deallocator:flags:)](coremedia/cmblockbuffer/append(buffer:deallocator:flags:)-1ibzz.md)
- [CMBlockBuffer.CustomBlockAllocator](coremedia/cmblockbuffer/customblockallocator.md)
- [CMBlockBuffer.CustomBlockDeallocator](coremedia/cmblockbuffer/customblockdeallocator.md)
- [append(bufferReference:flags:)](coremedia/cmblockbuffer/append(bufferreference:flags:).md)
- [assureBlockMemory()](coremedia/cmblockbuffer/assureblockmemory().md)
- [withUnsafeMutableBytes(atOffset:_:)](coremedia/cmblockbuffer/withunsafemutablebytes(atoffset:_:).md)

### Inspecting a Block Buffer

- [isEmpty](coremedia/cmblockbuffer/isempty.md)

### Accessing the Type Identifier

- [typeID](coremedia/cmblockbuffer/typeid.md)

### Data Types

- [CMBlockBuffer.Error](coremedia/cmblockbuffer/error.md)
- [CMBlockBuffer.Flags](coremedia/cmblockbuffer/flags.md)
- [CMBlockBuffer.Slice](coremedia/cmblockbuffer/slice.md)

### Initializers

- [init(referencing:)](coremedia/cmblockbuffer/init(referencing:).md)

### Type Aliases

- [CMBlockBuffer.T](coremedia/cmblockbuffer/t.md)

## Relationships

### Conforms To

- [CMAttachmentBearerProtocol](coremedia/cmattachmentbearerprotocol.md)
- [CMBlockBufferProtocol](coremedia/cmblockbufferprotocol.md)
- [Copyable](swift/copyable.md)
- [Equatable](swift/equatable.md)
- [Escapable](swift/escapable.md)
- [Hashable](swift/hashable.md)

## See Also

### Data Types

- [CMBlockBufferProtocol](coremedia/cmblockbufferprotocol.md)