GstAppSinkAdapter Class Reference

Bridges a GStreamer appsink to a Qt QVideoSink. More...

#include <GstAppSinkAdapter.h>

Inheritance diagram for GstAppSinkAdapter:

Collaboration diagram for GstAppSinkAdapter:

Signals
void	frameCountsChanged ()

Public Member Functions
	GstAppSinkAdapter (QObject *parent=nullptr)
	Frames that reached the appsink sink pad (counted via pad probe).
	~GstAppSinkAdapter () override
bool	setup (GstElement *sinkBin, QVideoSink *videoSink)
void	teardown ()
	Disconnect the callback (safe to call multiple times).
void	requestLatencyRefresh () noexcept
	Signal the adapter to refresh pipeline latency on the next streaming-thread tick.
void	setActive (bool active)
void	setRefreshRate (qreal hz)
void	setSmoothingEnabled (bool enabled, qreal refreshHz)
quint64	gpuFrameCount () const noexcept
quint64	cpuFrameCount () const noexcept
quint64	gpuFallbackCount () const noexcept
quint64	appsinkInputFrames () const noexcept
quint64	appsinkDroppedFrames () const noexcept

Detailed Description

Bridges a GStreamer appsink to a Qt QVideoSink.

Each decoded frame arriving at the appsink is copied into a QVideoFrame and pushed to the QVideoSink, which renders through Qt's native RHI backend (Metal on macOS, Vulkan/D3D elsewhere).

Definition at line 43 of file GstAppSinkAdapter.h.

Constructor & Destructor Documentation

GstAppSinkAdapter()

GstAppSinkAdapter::GstAppSinkAdapter ( QObject *  parent = nullptr )

explicit

Frames that reached the appsink sink pad (counted via pad probe).

Frames the appsink dropped because of max-buffers=1, drop=true queue overflow. Distinct from decoder-level QoS drops surfaced by GstVideoReceiver.

Definition at line 339 of file GstAppSinkAdapter.cc.

~GstAppSinkAdapter()

GstAppSinkAdapter::~GstAppSinkAdapter ( )

override

Definition at line 345 of file GstAppSinkAdapter.cc.

References teardown().

Member Function Documentation

appsinkDroppedFrames()

quint64 GstAppSinkAdapter::appsinkDroppedFrames ( ) const

noexcept

Definition at line 1281 of file GstAppSinkAdapter.cc.

appsinkInputFrames()

quint64 GstAppSinkAdapter::appsinkInputFrames ( ) const

noexcept

Definition at line 1276 of file GstAppSinkAdapter.cc.

cpuFrameCount()

quint64 GstAppSinkAdapter::cpuFrameCount ( ) const

noexcept

Definition at line 1236 of file GstAppSinkAdapter.cc.

frameCountsChanged

void GstAppSinkAdapter::frameCountsChanged ( )

signal

Referenced by setup().

gpuFallbackCount()

quint64 GstAppSinkAdapter::gpuFallbackCount ( ) const

noexcept

Definition at line 1242 of file GstAppSinkAdapter.cc.

gpuFrameCount()

quint64 GstAppSinkAdapter::gpuFrameCount ( ) const

noexcept

Definition at line 1211 of file GstAppSinkAdapter.cc.

requestLatencyRefresh()

void GstAppSinkAdapter::requestLatencyRefresh ( )

inlinenoexcept

Signal the adapter to refresh pipeline latency on the next streaming-thread tick.

Definition at line 68 of file GstAppSinkAdapter.h.

Referenced by GStreamer::setupAppSinkAdapter().

setActive()

void GstAppSinkAdapter::setActive

(

bool

active

)

Gate frame delivery without tearing the pipeline down. When set to false the next frame seen is a single empty QVideoFrame (clears the sink), and subsequent samples are dropped at the appsink callback until re-enabled. Mirrors Qt's QVideoSink::isActive gate (qgstvideorenderersink.cpp:345-355). Use when switching streams to avoid the previous stream's last frame ghosting on the QML output.

Definition at line 727 of file GstAppSinkAdapter.cc.

Referenced by GStreamer::setAppSinkAdaptersActive(), and GStreamer::setupAppSinkAdapter().

setRefreshRate()

void GstAppSinkAdapter::setRefreshRate

(

qreal

hz

)

Display refresh-rate baseline for appsink max-time (max(1/refreshHz, 1/streamFps) applied at each caps change). Call once from the GUI thread after setup(); pass 0 to leave the bin's 33 ms default.

Definition at line 499 of file GstAppSinkAdapter.cc.

setSmoothingEnabled()

void GstAppSinkAdapter::setSmoothingEnabled	(	bool	enabled,
		qreal	refreshHz
	)

Opt-in OBS-style smoothing: 3-deep ring, display-rate timer picks the frame nearest the PTS-anchored expected presentation time. Adds up to one frame of latency. refreshHz <= 0 falls back to 60 Hz tick.

Definition at line 518 of file GstAppSinkAdapter.cc.

setup()

bool GstAppSinkAdapter::setup	(	GstElement *	sinkBin,
		QVideoSink *	videoSink
	)

Connect to the named appsink inside sinkBin and push frames to videoSink. Returns true on success.

Definition at line 350 of file GstAppSinkAdapter.cc.

References frameCountsChanged(), gst_qgc_video_sink_bin_get_appsink(), and teardown().

teardown()

void GstAppSinkAdapter::teardown

(

)

Disconnect the callback (safe to call multiple times).

Definition at line 614 of file GstAppSinkAdapter.cc.

Referenced by setup(), and ~GstAppSinkAdapter().

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The documentation for this class was generated from the following files:

• src/VideoManager/VideoReceiver/GStreamer/GstAppSinkAdapter.h
• src/VideoManager/VideoReceiver/GStreamer/GstAppSinkAdapter.cc