Trait VideoDecoderBackend 

pub trait VideoDecoderBackend: Sized {
    type Session: VideoDecoderBackendSession;

    // Required methods
    fn new_session(&mut self, id: u32) -> IoctlResult<Self::Session>;
    fn close_session(&mut self, session: Self::Session);
    fn enum_formats(
        &self,
        session: &VideoDecoderSession<Self::Session>,
        direction: QueueDirection,
        index: u32,
    ) -> Option<v4l2_fmtdesc>;
    fn frame_sizes(&self, pixel_format: u32) -> Option<v4l2_frmsize_stepwise>;
    fn adjust_format(
        &self,
        session: &Self::Session,
        direction: QueueDirection,
        format: V4l2MplaneFormat,
    ) -> V4l2MplaneFormat;
    fn apply_format(
        &self,
        session: &mut Self::Session,
        direction: QueueDirection,
        format: &V4l2MplaneFormat,
    );
}

Trait for actual implementations of video decoding, to be used with VideoDecoder.

VideoDecoder takes care of (mostly) abstracting V4L2 away ; implementors of this trait are the ones that provide the actual video decoding service.

Required Associated Types

type Session: VideoDecoderBackendSession

Required Methods

fn new_session(&mut self, id: u32) -> IoctlResult<Self::Session>

Create a new session with the provided id.

fn close_session(&mut self, session: Self::Session)

Close and destroy session.

fn enum_formats( &self, session: &VideoDecoderSession<Self::Session>, direction: QueueDirection, index: u32, ) -> Option<v4l2_fmtdesc>

Returns the format at index for the given queue direction, or None if index is out of bounds.

fn frame_sizes(&self, pixel_format: u32) -> Option<v4l2_frmsize_stepwise>

Returns the supported frame sizes for pixel_format, or None if the format is not supported.

fn adjust_format( &self, session: &Self::Session, direction: QueueDirection, format: V4l2MplaneFormat, ) -> V4l2MplaneFormat

Adjust format to make it applicable to the queue with the given direction for the current session.

This method doesn’t fail, implementations must return the closest acceptable format that can be applied unchanged with Self::apply_format.

fn apply_format( &self, session: &mut Self::Session, direction: QueueDirection, format: &V4l2MplaneFormat, )

Applies format to the queue of the given direction. The format is adjusted if needed.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors