From e87f7b7b6885c63ad35ac4f6d0cd4d74e1d36d70 Mon Sep 17 00:00:00 2001
From: Vicki Pfau <vi@endrift.com>
Date: Fri, 9 Sep 2022 16:37:56 -0700
Subject: [PATCH] Qt: Use FFmpeg to convert additional camera formats, if
 available

---
 CHANGES                         |  1 +
 src/platform/qt/VideoDumper.cpp | 68 +++++++++++++++++++++++++++++++++
 src/platform/qt/VideoDumper.h   | 13 +++++++
 3 files changed, 82 insertions(+)

diff --git a/CHANGES b/CHANGES
index afb21e008..8e02fa02e 100644
--- a/CHANGES
+++ b/CHANGES
@@ -106,6 +106,7 @@ Misc:
  - Qt: Boot both a multiboot image and ROM with CLI args (closes mgba.io/i/1941)
  - Qt: Improve cheat parsing (fixes mgba.io/i/2297)
  - Qt: Change lossless setting to use WavPack audio
+ - Qt: Use FFmpeg to convert additional camera formats, if available
  - SDL: Support exposing an axis directly as the gyro value (closes mgba.io/i/2531)
  - Windows: Attach to console if present
  - Vita: Add bilinear filtering option (closes mgba.io/i/344)
diff --git a/src/platform/qt/VideoDumper.cpp b/src/platform/qt/VideoDumper.cpp
index 392030277..7c5345c55 100644
--- a/src/platform/qt/VideoDumper.cpp
+++ b/src/platform/qt/VideoDumper.cpp
@@ -23,6 +23,9 @@ bool VideoDumper::present(const QVideoFrame& frame) {
 	QVideoFrame::PixelFormat vFormat = mappedFrame.pixelFormat();
 	QImage::Format format = QVideoFrame::imageFormatFromPixelFormat(vFormat);
 	bool swap = false;
+#ifdef USE_FFMPEG
+	bool useScaler = false;
+#endif
 	if (format == QImage::Format_Invalid) {
 		if (vFormat < QVideoFrame::Format_BGRA5658_Premultiplied) {
 			vFormat = static_cast<QVideoFrame::PixelFormat>(vFormat - QVideoFrame::Format_BGRA32 + QVideoFrame::Format_ARGB32);
@@ -34,11 +37,68 @@ bool VideoDumper::present(const QVideoFrame& frame) {
 			}
 			swap = true;
 		} else {
+#ifdef USE_FFMPEG
+			enum AVPixelFormat pixelFormat;
+			switch (vFormat) {
+			case QVideoFrame::Format_YUV420P:
+				pixelFormat = AV_PIX_FMT_YUV420P;
+				break;
+			case QVideoFrame::Format_YUV422P:
+				pixelFormat = AV_PIX_FMT_YUV422P;
+				break;
+			case QVideoFrame::Format_YUYV:
+				pixelFormat = AV_PIX_FMT_YUYV422;
+				break;
+			case QVideoFrame::Format_UYVY:
+				pixelFormat = AV_PIX_FMT_UYVY422;
+				break;
+			case QVideoFrame::Format_NV12:
+				pixelFormat = AV_PIX_FMT_NV12;
+				break;
+			case QVideoFrame::Format_NV21:
+				pixelFormat = AV_PIX_FMT_NV12;
+				break;
+			default:
+				return false;
+			}
+			format = QImage::Format_RGB888;
+			useScaler = true;
+			if (pixelFormat != m_pixfmt || m_scalerSize != mappedFrame.size()) {
+				if (m_scaler) {
+					sws_freeContext(m_scaler);
+				}
+				m_scaler = sws_getContext(mappedFrame.width(), mappedFrame.height(), pixelFormat,
+				                          mappedFrame.width(), mappedFrame.height(), AV_PIX_FMT_RGB24,
+				                          SWS_POINT, nullptr, nullptr, nullptr);
+				m_scalerSize = mappedFrame.size();
+				m_pixfmt = pixelFormat;
+			}
+#else
 			return false;
+#endif
 		}
 	}
 	uchar* bits = mappedFrame.bits();
+#ifdef USE_FFMPEG
+	QImage image;
+	if (!useScaler) {
+		image = QImage(bits, mappedFrame.width(), mappedFrame.height(), mappedFrame.bytesPerLine(), format);
+	}
+	if (useScaler) {
+		image = QImage(mappedFrame.width(), mappedFrame.height(), format);
+		const uint8_t* planes[8] = {0};
+		int strides[8] = {0};
+		for (int plane = 0; plane < mappedFrame.planeCount(); ++plane) {
+			planes[plane] = mappedFrame.bits(plane);
+			strides[plane] = mappedFrame.bytesPerLine(plane);
+		}
+		uint8_t* outBits = image.bits();
+		int outStride = image.bytesPerLine();
+		sws_scale(m_scaler, planes, strides, 0, mappedFrame.height(), &outBits, &outStride);
+	} else
+#else
 	QImage image(bits, mappedFrame.width(), mappedFrame.height(), mappedFrame.bytesPerLine(), format);
+#endif
 	if (swap) {
 		image = image.rgbSwapped();
 	} else if (surfaceFormat().scanLineDirection() != QVideoSurfaceFormat::BottomToTop) {
@@ -66,5 +126,13 @@ QList<QVideoFrame::PixelFormat> VideoDumper::supportedPixelFormats(QAbstractVide
 	list.append(QVideoFrame::Format_BGRA32_Premultiplied);
 	list.append(QVideoFrame::Format_BGR565);
 	list.append(QVideoFrame::Format_BGR555);
+#ifdef USE_FFMPEG
+	list.append(QVideoFrame::Format_YUYV);
+	list.append(QVideoFrame::Format_UYVY);
+	list.append(QVideoFrame::Format_YUV422P);
+	list.append(QVideoFrame::Format_YUV420P);
+	list.append(QVideoFrame::Format_NV12);
+	list.append(QVideoFrame::Format_NV21);
+#endif
 	return list;
 }
diff --git a/src/platform/qt/VideoDumper.h b/src/platform/qt/VideoDumper.h
index 081fe3b45..c22688c2b 100644
--- a/src/platform/qt/VideoDumper.h
+++ b/src/platform/qt/VideoDumper.h
@@ -7,6 +7,12 @@
 
 #include <QAbstractVideoSurface>
 
+#ifdef USE_FFMPEG
+extern "C" {
+#include <libswscale/swscale.h>
+}
+#endif
+
 namespace QGBA {
 
 class VideoDumper : public QAbstractVideoSurface {
@@ -20,6 +26,13 @@ public:
 
 signals:
 	void imageAvailable(const QImage& image);
+
+private:
+#ifdef USE_FFMPEG
+	AVPixelFormat m_pixfmt = AV_PIX_FMT_NONE;
+	SwsContext* m_scaler = nullptr;
+	QSize m_scalerSize;
+#endif
 };
 
 }