AVHWFramesContext

public final class AVHWFramesContext

This struct describes a set or pool of hardware frames (i.e. those with data not located in normal system memory). All the frames in the pool are assumed to be allocated in the same way and interchangeable.

This struct is reference-counted with the AVBuffer mechanism and tied to a given AVHWDeviceContext instance. The init(deviceContext:) constructor yields a reference, whose data field points to the actual AVHWFramesContext struct.

  • Create an AVHWFramesContext tied to a given device context.

    Declaration

    Swift

    public init(deviceContext: AVHWDeviceContext)

    Parameters

    deviceContext

    a AVHWDeviceContext instance.

  • A reference to the parent AVHWDeviceContext.

    Declaration

    Swift

    public var deviceContext: AVHWDeviceContext { get }

  • The pixel format identifying the underlying HW surface type. Must be a hwaccel format, i.e. the corresponding descriptor must have the AV_PIX_FMT_FLAG_HWACCEL flag set.

    Must be set by the user before calling initialize().

    Declaration

    Swift

    public var pixelFormat: AVPixelFormat { get set }

  • The pixel format identifying the actual data layout of the hardware frames.

    Must be set by the caller before calling initialize().

    Note

    When the underlying API does not provide the exact data layout, but only the colorspace/bit depth, this field should be set to the fully planar version of that format (e.g. for 8-bit 420 YUV it should be AVPixelFormat.YUV420P, not AVPixelFormat.NV12 or anything else).

    Declaration

    Swift

    public var swPixelFormat: AVPixelFormat { get set }

  • The width of the frames in this pool.

    Must be set by the user before calling initialize().

    Declaration

    Swift

    public var width: Int { get set }

  • The height of the frames in this pool.

    Must be set by the user before calling initialize().

    Declaration

    Swift

    public var height: Int { get set }

  • Initial size of the frame pool. If a device type does not support dynamically resizing the pool, then this is also the maximum pool size.

    May be set by the caller before calling initialize(). Must be set if pool is nil and the device type does not support dynamic pools.

    Declaration

    Swift

    public var initialPoolSize: Int { get set }

  • Finalize the context before use. This function must be called after the context is filled with all the required information and before it is attached to any frames.

    Throws

    AVError

    Declaration

    Swift

    public func initialize() throws

  • Allocate a new frame attached to the given AVHWFramesContext.

    Throws

    AVError

    Declaration

    Swift

    public func allocBuffer(frame: AVFrame) throws

    Parameters

    frame

    an empty (freshly allocated or unreffed) frame to be filled with newly allocated buffers.

  • Get a list of possible source or target formats usable in AVFrame.transferData(from:).

    Declaration

    Swift

    public func getPixelFormats(_ direction: AVHWFrameTransferDirection) -> [AVPixelFormat]?

    Parameters

    direction

    the direction of the transfer

    Return Value

    supported pixel formats