pica-client: VAAPI hardware acceleration

1 files changed, 97 insertions, 0 deletions

diff --git a/pica-client/vaapivideowidget.h b/pica-client/vaapivideowidget.h
new file mode 100644
index 0000000..0aebef5
--- /dev/null
+++ b/pica-client/vaapivideowidget.h
@@ -0,0 +1,97 @@
+/*
+	(c) Copyright  2012 - 2026 Anton Sviridenko
+	https://picapica.im
+
+	This program is free software: you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, version 3.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+#ifndef VAAPIVIDEOWIDGET_H
+#define VAAPIVIDEOWIDGET_H
+
+#ifdef HAVE_VAAPI
+
+#include "vaapi.h"
+
+#include <QOpenGLWidget>
+#include <QOpenGLFunctions>
+#include <QOpenGLShaderProgram>
+#include <QString>
+
+// Draws frames that are still sitting in GPU memory as VA surfaces, without
+// bringing them back through system memory on the way.
+//
+// The surface is exported as DMA-BUF file descriptors, imported into EGL as
+// images, and bound to OpenGL textures - one for the luma plane and one for
+// the interleaved chroma plane of an NV12 frame - which a fragment shader
+// then converts to RGB while drawing. Nothing copies the picture; the GPU
+// keeps it where the decoder left it.
+//
+// The alternative, vaPutSurface() onto an X11 Drawable, was not an option
+// here: the client runs on Wayland, where there is no such drawable, and
+// Qt5X11Extras is not installed either. EGL works on both Wayland and X11.
+class VaapiVideoWidget : public QOpenGLWidget, protected QOpenGLFunctions
+{
+	Q_OBJECT
+public:
+	explicit VaapiVideoWidget(QWidget *parent = nullptr);
+	~VaapiVideoWidget() override;
+
+	// Whether the last frame could actually be drawn. False means the EGL
+	// import failed and nothing is being shown, so a caller can fall back to
+	// the software path rather than leave a blank widget.
+	bool isWorking() const { return m_working; }
+
+public slots:
+	// Takes the frame to draw next, replacing any previous one that has not
+	// been drawn yet - for live video the newest frame is the one that
+	// matters, which is the same policy the decode queue follows.
+	void setFrame(AVFramePtr frame);
+
+	// Drops the current frame and clears the widget.
+	void clearFrame();
+
+signals:
+	// Raised once if the frame cannot be imported for drawing, carrying the
+	// reason. The widget stops trying after that.
+	void renderingFailed(QString message);
+
+protected:
+	void initializeGL() override;
+	void paintGL() override;
+	void resizeGL(int w, int h) override;
+
+private:
+	// Builds the two textures for the current frame out of the surface's
+	// DMA-BUF handles. Returns false and leaves nothing bound on failure.
+	bool importFrame();
+
+	// Releases the EGL images and the file descriptors the export handed
+	// over. Not closing those descriptors leaks them once per frame, which
+	// exhausts the process's descriptors within minutes.
+	void releaseImports();
+
+	AVFramePtr m_frame;
+	QOpenGLShaderProgram *m_program;
+	unsigned int m_textures[2];
+	void *m_images[2];
+	int m_dmabufFds[4];
+	int m_numFds;
+	int m_frameWidth;
+	int m_frameHeight;
+	bool m_working;
+	bool m_reportedFailure;
+	bool m_describedSurface;
+};
+
+#endif // HAVE_VAAPI
+
+#endif // VAAPIVIDEOWIDGET_H