GstBase.BaseTransform

GObject.Object
    ╰──GObject.InitiallyUnowned
        ╰──Gst.Object
            ╰──Gst.Element
                ╰──GstBase.BaseTransform

GstBase.BaseTransform.prototype.get_allocator

function GstBase.BaseTransform.prototype.get_allocator(): {
    // javascript wrapper for 'gst_base_transform_get_allocator'
}

Lets GstBase.BaseTransform sub-classes know the memory allocator used by the base class and its params.

Unref the allocator after use.

GstBase.BaseTransform.prototype.get_buffer_pool

function GstBase.BaseTransform.prototype.get_buffer_pool(): {
    // javascript wrapper for 'gst_base_transform_get_buffer_pool'
}

GstBase.BaseTransform.prototype.is_in_place

function GstBase.BaseTransform.prototype.is_in_place(): {
    // javascript wrapper for 'gst_base_transform_is_in_place'
}

See if trans is configured as a in_place transform.

GstBase.BaseTransform.prototype.is_passthrough

function GstBase.BaseTransform.prototype.is_passthrough(): {
    // javascript wrapper for 'gst_base_transform_is_passthrough'
}

See if trans is configured as a passthrough transform.

GstBase.BaseTransform.prototype.is_qos_enabled

function GstBase.BaseTransform.prototype.is_qos_enabled(): {
    // javascript wrapper for 'gst_base_transform_is_qos_enabled'
}

Queries if the transform will handle QoS.

GstBase.BaseTransform.prototype.reconfigure

function GstBase.BaseTransform.prototype.reconfigure(): {
    // javascript wrapper for 'gst_base_transform_reconfigure'
}

Negotiates src pad caps with downstream elements if the source pad is marked as needing reconfiguring. Unmarks GST_PAD_FLAG_NEED_RECONFIGURE in any case. But marks it again if negotiation fails.

Do not call this in the vfunc_transform or vfunc_transform_ip vmethod. Call this in vfunc_submit_input_buffer, vfunc_prepare_output_buffer or in vfunc_generate_output before any output buffer is allocated.

It will be default be called when handling an ALLOCATION query or at the very beginning of the default vfunc_submit_input_buffer implementation.

Since : 1.18

GstBase.BaseTransform.prototype.reconfigure_sink

function GstBase.BaseTransform.prototype.reconfigure_sink(): {
    // javascript wrapper for 'gst_base_transform_reconfigure_sink'
}

Instructs trans to request renegotiation upstream. This function is typically called after properties on the transform were set that influence the input format.

GstBase.BaseTransform.prototype.reconfigure_src

function GstBase.BaseTransform.prototype.reconfigure_src(): {
    // javascript wrapper for 'gst_base_transform_reconfigure_src'
}

Instructs trans to renegotiate a new downstream transform on the next buffer. This function is typically called after properties on the transform were set that influence the output format.

GstBase.BaseTransform.prototype.set_gap_aware

function GstBase.BaseTransform.prototype.set_gap_aware(gap_aware: Number): {
    // javascript wrapper for 'gst_base_transform_set_gap_aware'
}

If gap_aware is false (the default), output buffers will have the Gst.BufferFlags.GAP flag unset.

If set to true, the element must handle output buffers with this flag set correctly, i.e. it can assume that the buffer contains neutral data but must unset the flag if the output is no neutral data.

MT safe.

GstBase.BaseTransform.prototype.set_in_place

function GstBase.BaseTransform.prototype.set_in_place(in_place: Number): {
    // javascript wrapper for 'gst_base_transform_set_in_place'
}

Determines whether a non-writable buffer will be copied before passing to the transform_ip function.

• Always true if no transform function is implemented.
• Always false if ONLY transform function is implemented.

MT safe.

GstBase.BaseTransform.prototype.set_passthrough

function GstBase.BaseTransform.prototype.set_passthrough(passthrough: Number): {
    // javascript wrapper for 'gst_base_transform_set_passthrough'
}

Set passthrough mode for this filter by default. This is mostly useful for filters that do not care about negotiation.

Always true for filters which don't implement either a transform or transform_ip or generate_output method.

MT safe.

GstBase.BaseTransform.prototype.set_prefer_passthrough

function GstBase.BaseTransform.prototype.set_prefer_passthrough(prefer_passthrough: Number): {
    // javascript wrapper for 'gst_base_transform_set_prefer_passthrough'
}

If prefer_passthrough is true (the default), trans will check and prefer passthrough caps from the list of caps returned by the transform_caps vmethod.

If set to false, the element must order the caps returned from the transform_caps function in such a way that the preferred format is first in the list. This can be interesting for transforms that can do passthrough transforms but prefer to do something else, like a capsfilter.

MT safe.

Since : 1.0.1

GstBase.BaseTransform.prototype.set_qos_enabled

function GstBase.BaseTransform.prototype.set_qos_enabled(enabled: Number): {
    // javascript wrapper for 'gst_base_transform_set_qos_enabled'
}

Enable or disable QoS handling in the transform.

MT safe.

GstBase.BaseTransform.prototype.update_qos

function GstBase.BaseTransform.prototype.update_qos(proportion: Number, diff: Number, timestamp: Number): {
    // javascript wrapper for 'gst_base_transform_update_qos'
}

Set the QoS parameters in the transform. This function is called internally when a QOS event is received but subclasses can provide custom information when needed.

MT safe.

GstBase.BaseTransform.prototype.update_src_caps

function GstBase.BaseTransform.prototype.update_src_caps(updated_caps: Gst.Caps): {
    // javascript wrapper for 'gst_base_transform_update_src_caps'
}

Updates the srcpad caps and sends the caps downstream. This function can be used by subclasses when they have already negotiated their caps but found a change in them (or computed new information). This way, they can notify downstream about that change without losing any buffer.

Since : 1.6

qos

“qos” Number

Flags : Read / Write

vfunc_accept_caps

function vfunc_accept_caps(trans: GstBase.BaseTransform, direction: Gst.PadDirection, caps: Gst.Caps): {
    // javascript implementation of the 'accept_caps' virtual method
}

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.

vfunc_before_transform

function vfunc_before_transform(trans: GstBase.BaseTransform, buffer: Gst.Buffer): {
    // javascript implementation of the 'before_transform' virtual method
}

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.

vfunc_copy_metadata

function vfunc_copy_metadata(trans: GstBase.BaseTransform, input: Gst.Buffer, outbuf: Gst.Buffer): {
    // javascript implementation of the 'copy_metadata' virtual method
}

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.

vfunc_decide_allocation

function vfunc_decide_allocation(trans: GstBase.BaseTransform, query: Gst.Query): {
    // javascript implementation of the 'decide_allocation' virtual method
}

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.

vfunc_filter_meta

function vfunc_filter_meta(trans: GstBase.BaseTransform, query: Gst.Query, api: GObject.Type, params: Gst.Structure): {
    // javascript implementation of the 'filter_meta' virtual method
}

Return true if the metadata API should be proposed in the upstream allocation query. The default implementation is null and will cause all metadata to be removed.

vfunc_fixate_caps

function vfunc_fixate_caps(trans: GstBase.BaseTransform, direction: Gst.PadDirection, caps: Gst.Caps, othercaps: Gst.Caps): {
    // javascript implementation of the 'fixate_caps' virtual method
}

Optional. Given the pad in this direction and the given caps, fixate the caps on the other pad. The function takes ownership of othercaps and returns a fixated version of othercaps. othercaps is not guaranteed to be writable.

vfunc_generate_output

function vfunc_generate_output(trans: GstBase.BaseTransform): {
    // javascript implementation of the 'generate_output' virtual method
}

Called after each new input buffer is submitted repeatedly until it either generates an error or fails to generate an output buffer. The default implementation takes the contents of the queued_buf variable, generates an output buffer if needed by calling the class prepare_output_buffer, and then calls either transform or transform_ip. Elements that don't do 1-to-1 transformations of input to output buffers can either return GST_BASE_TRANSFORM_FLOW_DROPPED or simply not generate an output buffer until they are ready to do so. (Since: 1.6)

vfunc_get_unit_size

function vfunc_get_unit_size(trans: GstBase.BaseTransform, caps: Gst.Caps): {
    // javascript implementation of the 'get_unit_size' virtual method
}

Required if the transform is not in-place. Get the size in bytes of one unit for the given caps.

vfunc_prepare_output_buffer

function vfunc_prepare_output_buffer(trans: GstBase.BaseTransform, input: Gst.Buffer): {
    // javascript implementation of the 'prepare_output_buffer' virtual method
}

Optional. Subclasses can override this to do their own allocation of output buffers. Elements that only do analysis can return a subbuffer or even just return a reference to the input buffer (if in passthrough mode). The default implementation will use the negotiated allocator or bufferpool and transform_size to allocate an output buffer or it will return the input buffer in passthrough mode.

vfunc_propose_allocation

function vfunc_propose_allocation(trans: GstBase.BaseTransform, decide_query: Gst.Query, query: Gst.Query): {
    // javascript implementation of the 'propose_allocation' virtual method
}

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 null 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.

vfunc_query

function vfunc_query(trans: GstBase.BaseTransform, direction: Gst.PadDirection, query: Gst.Query): {
    // javascript implementation of the 'query' virtual method
}

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

vfunc_set_caps

function vfunc_set_caps(trans: GstBase.BaseTransform, incaps: Gst.Caps, outcaps: Gst.Caps): {
    // javascript implementation of the 'set_caps' virtual method
}

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

vfunc_sink_event

function vfunc_sink_event(trans: GstBase.BaseTransform, event: Gst.Event): {
    // javascript implementation of the 'sink_event' virtual method
}

Optional. Event handler on the sink pad. The default implementation handles the event and forwards it downstream.

vfunc_src_event

function vfunc_src_event(trans: GstBase.BaseTransform, event: Gst.Event): {
    // javascript implementation of the 'src_event' virtual method
}

Optional. Event handler on the source pad. The default implementation handles the event and forwards it upstream.

vfunc_start

function vfunc_start(trans: GstBase.BaseTransform): {
    // javascript implementation of the 'start' virtual method
}

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

vfunc_stop

function vfunc_stop(trans: GstBase.BaseTransform): {
    // javascript implementation of the 'stop' virtual method
}

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

vfunc_submit_input_buffer

function vfunc_submit_input_buffer(trans: GstBase.BaseTransform, is_discont: Number, input: Gst.Buffer): {
    // javascript implementation of the 'submit_input_buffer' virtual method
}

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)

vfunc_transform

function vfunc_transform(trans: GstBase.BaseTransform, inbuf: Gst.Buffer, outbuf: Gst.Buffer): {
    // javascript implementation of the 'transform' virtual method
}

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.

vfunc_transform_caps

function vfunc_transform_caps(trans: GstBase.BaseTransform, direction: Gst.PadDirection, caps: Gst.Caps, filter: Gst.Caps): {
    // javascript implementation of the 'transform_caps' virtual method
}

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

vfunc_transform_ip

function vfunc_transform_ip(trans: GstBase.BaseTransform, buf: Gst.Buffer): {
    // javascript implementation of the 'transform_ip' virtual method
}

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

vfunc_transform_meta

function vfunc_transform_meta(trans: GstBase.BaseTransform, outbuf: Gst.Buffer, meta: Gst.Meta, inbuf: Gst.Buffer): {
    // javascript implementation of the 'transform_meta' virtual method
}

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.

vfunc_transform_size

function vfunc_transform_size(trans: GstBase.BaseTransform, direction: Gst.PadDirection, caps: Gst.Caps, size: Number, othercaps: Gst.Caps): {
    // javascript implementation of the 'transform_size' virtual method
}

Optional. Given the size of a buffer in the given direction with the given caps, calculate the size in bytes of a buffer on the other pad with the given other caps. The default implementation uses get_unit_size and keeps the number of units the same.

GstBase.BASE_TRANSFORM_SINK_NAME

The name of the templates for the sink pad.

GstBase.BASE_TRANSFORM_SRC_NAME

The name of the templates for the source pad.