From c7108362fe5c11db4e268231f7dda1c44e6978a1 Mon Sep 17 00:00:00 2001
From: Lars Knoll <lars.knoll@qt.io>
Date: Thu, 20 May 2021 16:01:41 +0200
Subject: Improve gstreamer capture pipeline
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Avoid sync state changes that can not happen synchronously,
leading to very slow timeouts on the pipeline.

This makes the whole capture experience on Linux snappy.

Change-Id: Ib49d4d3962c861515a883fe61505e0d3f3178428
Reviewed-by: André de la Rocha <andre.rocha@qt.io>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
---
 .../mediacapture/qgstreamercameraimagecapture.cpp       |  2 +-
 .../gstreamer/mediacapture/qgstreamermediacapture.cpp   | 14 ++++++++------
 .../gstreamer/mediacapture/qgstreamermediaencoder.cpp   | 17 +++++++++++------
 3 files changed, 20 insertions(+), 13 deletions(-)

(limited to 'src/multimedia')

diff --git a/src/multimedia/platform/gstreamer/mediacapture/qgstreamercameraimagecapture.cpp b/src/multimedia/platform/gstreamer/mediacapture/qgstreamercameraimagecapture.cpp
index 9e803ead5..e19a9c28e 100644
--- a/src/multimedia/platform/gstreamer/mediacapture/qgstreamercameraimagecapture.cpp
+++ b/src/multimedia/platform/gstreamer/mediacapture/qgstreamercameraimagecapture.cpp
@@ -360,7 +360,7 @@ void QGstreamerCameraImageCapture::link()
     videoSrcPad = m_session->getVideoPad();
     videoSrcPad.link(bin.staticPad("sink"));
     bin.lockState(false);
-    bin.setStateSync(GST_STATE_PAUSED);
+    bin.setState(GST_STATE_PAUSED);
     gstPipeline.setStateSync(GST_STATE_PLAYING);
 }
 
diff --git a/src/multimedia/platform/gstreamer/mediacapture/qgstreamermediacapture.cpp b/src/multimedia/platform/gstreamer/mediacapture/qgstreamermediacapture.cpp
index 4c8d04e92..6fbd56cec 100644
--- a/src/multimedia/platform/gstreamer/mediacapture/qgstreamermediacapture.cpp
+++ b/src/multimedia/platform/gstreamer/mediacapture/qgstreamermediacapture.cpp
@@ -99,8 +99,9 @@ void QGstreamerMediaCapture::setCamera(QPlatformCamera *camera)
     if (gstCamera == control)
         return;
 
-    //auto state = gstPipeline.state();
-    gstPipeline.setStateSync(GST_STATE_PAUSED);
+    auto state = gstPipeline.state();
+    if (state != GST_STATE_PAUSED)
+        gstPipeline.setStateSync(GST_STATE_PAUSED);
 
     if (gstVideoTee.isNull()) {
         gstVideoTee = QGstElement("tee", "videotee");
@@ -120,13 +121,14 @@ void QGstreamerMediaCapture::setCamera(QPlatformCamera *camera)
 
     gstCamera = control;
     if (gstCamera) {
-        gstPipeline.add(gstCamera->gstElement());
+        QGstElement camera = gstCamera->gstElement();
+        gstPipeline.add(camera);
         gstCamera->gstElement().link(gstVideoTee);
-        gstCamera->gstElement().setStateSync(gstPipeline.state());
         gstCamera->setCaptureSession(this);
-        //gstCamera->setPipeline(gstPipeline); // needed?
+        camera.setState(GST_STATE_PAUSED);
     }
-    gstPipeline.setStateSync(GST_STATE_PLAYING);
+    if (state != GST_STATE_PAUSED)
+        gstPipeline.setState(state);
 
     emit cameraChanged();
     gstPipeline.dumpGraph("camera");
diff --git a/src/multimedia/platform/gstreamer/mediacapture/qgstreamermediaencoder.cpp b/src/multimedia/platform/gstreamer/mediacapture/qgstreamermediaencoder.cpp
index 86b57139c..b73586a62 100644
--- a/src/multimedia/platform/gstreamer/mediacapture/qgstreamermediaencoder.cpp
+++ b/src/multimedia/platform/gstreamer/mediacapture/qgstreamermediaencoder.cpp
@@ -110,7 +110,7 @@ void QGstreamerMediaEncoder::updateStatus()
 
     auto newStatus = statusTable[state()][sessionState];
 
-    qCDebug(qLcMediaEncoder) << "updateStatus" << newStatus;
+    qCDebug(qLcMediaEncoder) << "updateStatus" << state() << sessionState << newStatus;
     statusChanged(newStatus);
 }
 
@@ -287,13 +287,18 @@ void QGstreamerMediaEncoder::record()
 {
     if (!m_session)
         return;
-    if (state() == QMediaEncoder::PausedState) {
+    auto oldState = state();
+    stateChanged(QMediaEncoder::RecordingState);
+
+    if (oldState == QMediaEncoder::PausedState) {
         // coming from paused state
+        stateChanged(QMediaEncoder::RecordingState);
         gstEncoder.setState(GST_STATE_PLAYING);
         updateStatus();
         return;
     }
 
+    updateStatus();
     // create new encoder
     if (m_requestedOutputLocation.isEmpty()) {
         QString container = m_resolvedSettings.mimeType().preferredSuffix();
@@ -322,9 +327,9 @@ void QGstreamerMediaEncoder::record()
         }
     }
 
-    gstEncoder.setStateSync(GST_STATE_PAUSED);
-    gstFileSink.setStateSync(GST_STATE_PAUSED);
-    gstPipeline.setStateSync(GST_STATE_PLAYING);
+    gstEncoder.setState(GST_STATE_PAUSED);
+    gstFileSink.setState(GST_STATE_PAUSED);
+    gstPipeline.setState(GST_STATE_PLAYING);
 
     m_duration.start();
     heartbeat.start();
@@ -360,7 +365,7 @@ void QGstreamerMediaEncoder::stop()
     m_session->releaseVideoPad(videoSrcPad);
     audioSrcPad = videoSrcPad = {};
 
-    gstPipeline.setStateSync(GST_STATE_PLAYING);
+    gstPipeline.setState(GST_STATE_PLAYING);
     //with live sources it's necessary to send EOS even to pipeline
     //before going to STOPPED state
     qCDebug(qLcMediaEncoder) << ">>>>>>>>>>>>> sending EOS";
-- 
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