Trait gstreamer_base::subclass::base_transform::BaseTransformImpl

pub trait BaseTransformImpl: BaseTransformImplExt + ElementImpl {
    const MODE: BaseTransformMode;
    const PASSTHROUGH_ON_SAME_CAPS: bool;
    const TRANSFORM_IP_ON_PASSTHROUGH: bool;

    // Provided methods
    fn start(&self) -> Result<(), ErrorMessage> { ... }
    fn stop(&self) -> Result<(), ErrorMessage> { ... }
    fn transform_caps(
        &self,
        direction: PadDirection,
        caps: &Caps,
        filter: Option<&Caps>,
    ) -> Option<Caps> { ... }
    fn fixate_caps(
        &self,
        direction: PadDirection,
        caps: &Caps,
        othercaps: Caps,
    ) -> Caps { ... }
    fn set_caps(
        &self,
        incaps: &Caps,
        outcaps: &Caps,
    ) -> Result<(), LoggableError> { ... }
    fn accept_caps(&self, direction: PadDirection, caps: &Caps) -> bool { ... }
    fn query(&self, direction: PadDirection, query: &mut QueryRef) -> bool { ... }
    fn transform_size(
        &self,
        direction: PadDirection,
        caps: &Caps,
        size: usize,
        othercaps: &Caps,
    ) -> Option<usize> { ... }
    fn unit_size(&self, caps: &Caps) -> Option<usize> { ... }
    fn sink_event(&self, event: Event) -> bool { ... }
    fn src_event(&self, event: Event) -> bool { ... }
    fn prepare_output_buffer(
        &self,
        inbuf: InputBuffer<'_>,
    ) -> Result<PrepareOutputBufferSuccess, FlowError> { ... }
    fn transform(
        &self,
        inbuf: &Buffer,
        outbuf: &mut BufferRef,
    ) -> Result<FlowSuccess, FlowError> { ... }
    fn transform_ip(
        &self,
        buf: &mut BufferRef,
    ) -> Result<FlowSuccess, FlowError> { ... }
    fn transform_ip_passthrough(
        &self,
        buf: &Buffer,
    ) -> Result<FlowSuccess, FlowError> { ... }
    fn propose_allocation(
        &self,
        decide_query: Option<&Allocation>,
        query: &mut Allocation,
    ) -> Result<(), LoggableError> { ... }
    fn decide_allocation(
        &self,
        query: &mut Allocation,
    ) -> Result<(), LoggableError> { ... }
    fn copy_metadata(
        &self,
        inbuf: &BufferRef,
        outbuf: &mut BufferRef,
    ) -> Result<(), LoggableError> { ... }
    fn transform_meta<'a>(
        &self,
        outbuf: &mut BufferRef,
        meta: MetaRef<'a, Meta>,
        inbuf: &'a BufferRef,
    ) -> bool { ... }
    fn before_transform(&self, inbuf: &BufferRef) { ... }
    fn submit_input_buffer(
        &self,
        is_discont: bool,
        inbuf: Buffer,
    ) -> Result<FlowSuccess, FlowError> { ... }
    fn generate_output(&self) -> Result<GenerateOutputSuccess, FlowError> { ... }
}

Required Associated Constants

const MODE: BaseTransformMode

const PASSTHROUGH_ON_SAME_CAPS: bool

const TRANSFORM_IP_ON_PASSTHROUGH: bool

Provided Methods

fn start(&self) -> Result<(), ErrorMessage>

Optional. Called when the element starts processing. Allows opening external resources.

fn stop(&self) -> Result<(), ErrorMessage>

Optional. Called when the element stops processing. Allows closing external resources.

fn transform_caps( &self, direction: PadDirection, caps: &Caps, filter: Option<&Caps>, ) -> Option<Caps>

Optional. Given the pad in this direction and the given caps, what caps are allowed on the other pad in this element ?

fn fixate_caps( &self, direction: PadDirection, caps: &Caps, othercaps: Caps, ) -> Caps

fn set_caps(&self, incaps: &Caps, outcaps: &Caps) -> Result<(), LoggableError>

Allows the subclass to be notified of the actual caps set.

fn accept_caps(&self, direction: PadDirection, caps: &Caps) -> bool

Optional. Subclasses can override this method to check if caps can be handled by the element. The default implementation might not be the most optimal way to check this in all cases.

fn query(&self, direction: PadDirection, query: &mut QueryRef) -> bool

Optional. Handle a requested query. Subclasses that implement this must chain up to the parent if they didn’t handle the query

fn transform_size( &self, direction: PadDirection, caps: &Caps, size: usize, othercaps: &Caps, ) -> Option<usize>

fn unit_size(&self, caps: &Caps) -> Option<usize>

fn sink_event(&self, event: Event) -> bool

fn src_event(&self, event: Event) -> bool

fn prepare_output_buffer( &self, inbuf: InputBuffer<'_>, ) -> Result<PrepareOutputBufferSuccess, FlowError>

fn transform( &self, inbuf: &Buffer, outbuf: &mut BufferRef, ) -> Result<FlowSuccess, FlowError>

Required if the element does not operate in-place. Transforms one incoming buffer to one outgoing buffer. The function is allowed to change size/timestamp/duration of the outgoing buffer.

fn transform_ip(&self, buf: &mut BufferRef) -> Result<FlowSuccess, FlowError>

Required if the element operates in-place. Transform the incoming buffer in-place.

fn transform_ip_passthrough( &self, buf: &Buffer, ) -> Result<FlowSuccess, FlowError>

fn propose_allocation( &self, decide_query: Option<&Allocation>, query: &mut Allocation, ) -> Result<(), LoggableError>

Propose buffer allocation parameters for upstream elements. This function must be implemented if the element reads or writes the buffer content. The query that was passed to the decide_allocation is passed in this method (or None when the element is in passthrough mode). The default implementation will pass the query downstream when in passthrough mode and will copy all the filtered metadata API in non-passthrough mode.

fn decide_allocation(&self, query: &mut Allocation) -> Result<(), LoggableError>

Setup the allocation parameters for allocating output buffers. The passed in query contains the result of the downstream allocation query. This function is only called when not operating in passthrough mode. The default implementation will remove all memory dependent metadata. If there is a filter_meta method implementation, it will be called for all metadata API in the downstream query, otherwise the metadata API is removed.

fn copy_metadata( &self, inbuf: &BufferRef, outbuf: &mut BufferRef, ) -> Result<(), LoggableError>

Optional. Copy the metadata from the input buffer to the output buffer. The default implementation will copy the flags, timestamps and offsets of the buffer.

fn transform_meta<'a>( &self, outbuf: &mut BufferRef, meta: MetaRef<'a, Meta>, inbuf: &'a BufferRef, ) -> bool

Optional. Transform the metadata on the input buffer to the output buffer. By default this method copies all meta without tags. Subclasses can implement this method and return true if the metadata is to be copied.

fn before_transform(&self, inbuf: &BufferRef)

Optional. This method is called right before the base class will start processing. Dynamic properties or other delayed configuration could be performed in this method.

fn submit_input_buffer( &self, is_discont: bool, inbuf: Buffer, ) -> Result<FlowSuccess, FlowError>

Function which accepts a new input buffer and pre-processes it. The default implementation performs caps (re)negotiation, then QoS if needed, and places the input buffer into the queued_buf member variable. If the buffer is dropped due to QoS, it returns GST_BASE_TRANSFORM_FLOW_DROPPED. If this input buffer is not contiguous with any previous input buffer, then is_discont is set to true. (Since: 1.6)

fn generate_output(&self) -> Result<GenerateOutputSuccess, FlowError>

Object Safety

This trait is not object safe.

Implementors