diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 635e9fd7e..6eae8bc32 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -10,7 +10,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-22.04, macos-latest, windows-2022]
+        os: [ubuntu-latest, macos-latest, windows-2022]
     env:
       CMAKE_BUILD_TYPE: Release
     steps:
@@ -31,10 +31,23 @@ jobs:
         if: runner.os == 'macOS'
         run: |
           brew update
-          brew install ninja pkg-config qt@6 ffmpeg openimageio opencolorio openexr portaudio expat opentimelineio
+          brew install ninja pkg-config qt@6 ffmpeg openimageio opencolorio openexr portaudio expat
           echo "$(brew --prefix qt@6)/bin" >> "$GITHUB_PATH"
           echo "CMAKE_PREFIX_PATH=$(brew --prefix qt@6)" >> "$GITHUB_ENV"
 
+      - name: Build OpenTimelineIO (macOS)
+        if: runner.os == 'macOS'
+        run: |
+          git clone --depth 1 --branch v0.16.0 https://github.com/PixarAnimationStudios/OpenTimelineIO.git
+          cmake -S OpenTimelineIO -B OpenTimelineIO/build -G Ninja \
+            -DOTIO_SHARED_LIBS=ON \
+            -DOTIO_PYTHON_BINDINGS=OFF \
+            -DCMAKE_BUILD_TYPE=Release \
+            -DCMAKE_INSTALL_PREFIX="${PWD}/otio-install"
+          cmake --build OpenTimelineIO/build
+          cmake --install OpenTimelineIO/build
+          echo "OTIO_LOCATION=${PWD}/otio-install" >> "$GITHUB_ENV"
+
       - name: Install Qt (Windows)
         if: runner.os == 'Windows'
         uses: jurplel/install-qt-action@v4
@@ -69,6 +82,7 @@ jobs:
             -DBUILD_TESTS=ON \
             -DBUILD_QT6=ON \
             -DOCIO_LOCATION=$(brew --prefix opencolorio) \
+            -DOTIO_LOCATION=${OTIO_LOCATION} \
             -DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}
 
       - name: Configure (Windows)
diff --git a/tests/gtest/CMakeLists.txt b/tests/gtest/CMakeLists.txt
index cc4de4fee..b235aa9d5 100644
--- a/tests/gtest/CMakeLists.txt
+++ b/tests/gtest/CMakeLists.txt
@@ -19,8 +19,14 @@ add_executable(olive-gtest
   plugin_support_image_test.cpp
   plugin_support_clip_test.cpp
   codec_frame_test.cpp
+  codec_exportcodec_test.cpp
+  codec_exportformat_test.cpp
+  codec_encoder_test.cpp
   task_taskmanager_test.cpp
   module_smoke_test.cpp
+  shader_resources_test.cpp
+  timeline_coordinate_test.cpp
+  timeline_workarea_test.cpp
 )
 
 target_sources(olive-gtest PRIVATE $<TARGET_OBJECTS:libolive-editor>)
diff --git a/tests/gtest/codec_encoder_test.cpp b/tests/gtest/codec_encoder_test.cpp
new file mode 100644
index 000000000..05d7bc1f2
--- /dev/null
+++ b/tests/gtest/codec_encoder_test.cpp
@@ -0,0 +1,99 @@
+#include <gtest/gtest.h>
+
+#include "codec/encoder.h"
+
+namespace {
+class TestEncoder final : public olive::Encoder {
+public:
+	explicit TestEncoder(const olive::EncodingParams &params)
+		: olive::Encoder(params)
+	{
+	}
+
+	bool Open() override
+	{
+		return true;
+	}
+
+	bool WriteFrame(olive::FramePtr, olive::core::rational) override
+	{
+		return true;
+	}
+
+	bool WriteAudio(const olive::SampleBuffer &) override
+	{
+		return true;
+	}
+
+	bool WriteSubtitle(const olive::SubtitleBlock *) override
+	{
+		return true;
+	}
+
+	void Close() override
+	{
+	}
+};
+}
+
+TEST(CodecEncoder, ImageSequenceFilenames)
+{
+	olive::EncodingParams params;
+	params.SetFilename(QStringLiteral("frame_[####].png"));
+	params.set_video_is_image_sequence(true);
+
+	olive::VideoParams video_params;
+	video_params.set_frame_rate(olive::core::rational(24, 1));
+	params.EnableVideo(video_params, olive::ExportCodec::kCodecPNG);
+
+	TestEncoder encoder(params);
+
+	EXPECT_TRUE(olive::Encoder::FilenameContainsDigitPlaceholder(
+		QStringLiteral("frame_[####].png")));
+	EXPECT_EQ(olive::Encoder::GetImageSequencePlaceholderDigitCount(
+				  QStringLiteral("frame_[####].png")),
+			  4);
+	EXPECT_EQ(olive::Encoder::FilenameRemoveDigitPlaceholder(
+				  QStringLiteral("frame_[####].png")),
+			  QStringLiteral("frame.png"));
+
+	const QString filename = encoder.GetFilenameForFrame(
+		olive::core::rational(1, 24));
+	EXPECT_EQ(filename, QStringLiteral("frame_0001.png"));
+}
+
+TEST(CodecEncoder, MatrixGeneration)
+{
+	using Method = olive::EncodingParams::VideoScalingMethod;
+
+	QMatrix4x4 stretch =
+		olive::EncodingParams::GenerateMatrix(Method::kStretch, 1920, 1080,
+											  1280, 720);
+	EXPECT_TRUE(qFuzzyCompare(stretch(0, 0), 1.0f));
+	EXPECT_TRUE(qFuzzyCompare(stretch(1, 1), 1.0f));
+
+	QMatrix4x4 fit =
+		olive::EncodingParams::GenerateMatrix(Method::kFit, 1920, 1080,
+											  1024, 1024);
+	EXPECT_TRUE(qFuzzyCompare(fit(0, 0), 1.0f));
+	EXPECT_FALSE(qFuzzyCompare(fit(1, 1), 1.0f));
+
+	QMatrix4x4 crop =
+		olive::EncodingParams::GenerateMatrix(Method::kCrop, 1920, 1080,
+											  1024, 1024);
+	EXPECT_FALSE(qFuzzyCompare(crop(0, 0), 1.0f));
+	EXPECT_TRUE(qFuzzyCompare(crop(1, 1), 1.0f));
+}
+
+TEST(CodecEncoder, TypeFromFormat)
+{
+	using olive::Encoder;
+	using olive::ExportFormat;
+
+	EXPECT_EQ(Encoder::GetTypeFromFormat(ExportFormat::kFormatPNG),
+			  Encoder::kEncoderTypeOIIO);
+	EXPECT_EQ(Encoder::GetTypeFromFormat(ExportFormat::kFormatDNxHD),
+			  Encoder::kEncoderTypeFFmpeg);
+	EXPECT_EQ(Encoder::GetTypeFromFormat(ExportFormat::kFormatCount),
+			  Encoder::kEncoderTypeNone);
+}
diff --git a/tests/gtest/codec_exportcodec_test.cpp b/tests/gtest/codec_exportcodec_test.cpp
new file mode 100644
index 000000000..cfae6fcc9
--- /dev/null
+++ b/tests/gtest/codec_exportcodec_test.cpp
@@ -0,0 +1,20 @@
+#include <gtest/gtest.h>
+
+#include "codec/exportcodec.h"
+
+TEST(CodecExportCodec, NamesAndFlags)
+{
+	using olive::ExportCodec;
+
+	EXPECT_EQ(ExportCodec::GetCodecName(ExportCodec::kCodecH264),
+			  QStringLiteral("H.264"));
+	EXPECT_EQ(ExportCodec::GetCodecName(ExportCodec::kCodecCount),
+			  QStringLiteral("Unknown"));
+
+	EXPECT_TRUE(ExportCodec::IsCodecAStillImage(ExportCodec::kCodecPNG));
+	EXPECT_FALSE(ExportCodec::IsCodecAStillImage(ExportCodec::kCodecH264));
+
+	EXPECT_TRUE(ExportCodec::IsCodecLossless(ExportCodec::kCodecPCM));
+	EXPECT_TRUE(ExportCodec::IsCodecLossless(ExportCodec::kCodecFLAC));
+	EXPECT_FALSE(ExportCodec::IsCodecLossless(ExportCodec::kCodecH265));
+}
diff --git a/tests/gtest/codec_exportformat_test.cpp b/tests/gtest/codec_exportformat_test.cpp
new file mode 100644
index 000000000..a27ffb727
--- /dev/null
+++ b/tests/gtest/codec_exportformat_test.cpp
@@ -0,0 +1,44 @@
+#include <gtest/gtest.h>
+
+#include "codec/exportformat.h"
+
+TEST(CodecExportFormat, NamesAndExtensions)
+{
+	using olive::ExportFormat;
+
+	EXPECT_EQ(ExportFormat::GetName(ExportFormat::kFormatDNxHD),
+			  QStringLiteral("DNxHD"));
+	EXPECT_EQ(ExportFormat::GetExtension(ExportFormat::kFormatDNxHD),
+			  QStringLiteral("mxf"));
+	EXPECT_EQ(ExportFormat::GetName(ExportFormat::kFormatCount),
+			  QStringLiteral("Unknown"));
+	EXPECT_TRUE(ExportFormat::GetExtension(ExportFormat::kFormatCount).isEmpty());
+}
+
+TEST(CodecExportFormat, CodecLists)
+{
+	using olive::ExportCodec;
+	using olive::ExportFormat;
+
+	const QList<ExportCodec::Codec> matroska_video =
+		ExportFormat::GetVideoCodecs(ExportFormat::kFormatMatroska);
+	EXPECT_TRUE(matroska_video.contains(ExportCodec::kCodecH264));
+	EXPECT_TRUE(matroska_video.contains(ExportCodec::kCodecVP9));
+
+	const QList<ExportCodec::Codec> ogg_audio =
+		ExportFormat::GetAudioCodecs(ExportFormat::kFormatOgg);
+	EXPECT_TRUE(ogg_audio.contains(ExportCodec::kCodecOpus));
+	EXPECT_TRUE(ogg_audio.contains(ExportCodec::kCodecVorbis));
+
+	const QList<ExportCodec::Codec> png_video =
+		ExportFormat::GetVideoCodecs(ExportFormat::kFormatPNG);
+	EXPECT_EQ(png_video, QList<ExportCodec::Codec>{ ExportCodec::kCodecPNG });
+
+	const QList<ExportCodec::Codec> srt_subs =
+		ExportFormat::GetSubtitleCodecs(ExportFormat::kFormatMatroska);
+	EXPECT_EQ(srt_subs, QList<ExportCodec::Codec>{ ExportCodec::kCodecSRT });
+
+	const QList<ExportCodec::Codec> wav_audio =
+		ExportFormat::GetAudioCodecs(ExportFormat::kFormatWAV);
+	EXPECT_EQ(wav_audio, QList<ExportCodec::Codec>{ ExportCodec::kCodecPCM });
+}
diff --git a/tests/gtest/shader_resources_test.cpp b/tests/gtest/shader_resources_test.cpp
new file mode 100644
index 000000000..8997a0d75
--- /dev/null
+++ b/tests/gtest/shader_resources_test.cpp
@@ -0,0 +1,26 @@
+#include <gtest/gtest.h>
+
+#include <QFile>
+
+TEST(Shaders, ResourcesAvailable)
+{
+	const QStringList shader_paths = {
+		QStringLiteral(":/shaders/default.frag"),
+		QStringLiteral(":/shaders/default.vert"),
+		QStringLiteral(":/shaders/yuv2rgb.frag"),
+		QStringLiteral(":/shaders/deinterlace2.frag"),
+		QStringLiteral(":/shaders/rgbhistogram.frag"),
+		QStringLiteral(":/shaders/rgbhistogram.vert")
+	};
+
+	for (const QString &path : shader_paths) {
+		QFile file(path);
+		ASSERT_TRUE(file.exists()) << "Missing shader resource: "
+								   << path.toStdString();
+		ASSERT_TRUE(file.open(QIODevice::ReadOnly))
+			<< "Failed to open shader resource: " << path.toStdString();
+		const QByteArray contents = file.readAll();
+		EXPECT_FALSE(contents.isEmpty())
+			<< "Shader resource is empty: " << path.toStdString();
+	}
+}
diff --git a/tests/gtest/timeline_coordinate_test.cpp b/tests/gtest/timeline_coordinate_test.cpp
new file mode 100644
index 000000000..527862e46
--- /dev/null
+++ b/tests/gtest/timeline_coordinate_test.cpp
@@ -0,0 +1,34 @@
+#include <gtest/gtest.h>
+
+#include "timeline/timelinecoordinate.h"
+
+TEST(TimelineCoordinate, DefaultAndSetters)
+{
+	olive::TimelineCoordinate coord;
+	EXPECT_EQ(coord.GetTrack().type(), olive::Track::kNone);
+	EXPECT_EQ(coord.GetTrack().index(), 0);
+
+	const olive::core::rational frame(10, 1);
+	olive::Track::Reference ref(olive::Track::kVideo, 2);
+
+	coord.SetFrame(frame);
+	coord.SetTrack(ref);
+
+	EXPECT_EQ(coord.GetFrame(), frame);
+	EXPECT_EQ(coord.GetTrack(), ref);
+}
+
+TEST(TimelineCoordinate, Constructors)
+{
+	const olive::core::rational frame(5, 1);
+	olive::Track::Reference ref(olive::Track::kAudio, 1);
+
+	olive::TimelineCoordinate with_ref(frame, ref);
+	EXPECT_EQ(with_ref.GetFrame(), frame);
+	EXPECT_EQ(with_ref.GetTrack(), ref);
+
+	olive::TimelineCoordinate with_type(frame, olive::Track::kSubtitle, 3);
+	EXPECT_EQ(with_type.GetFrame(), frame);
+	EXPECT_EQ(with_type.GetTrack().type(), olive::Track::kSubtitle);
+	EXPECT_EQ(with_type.GetTrack().index(), 3);
+}
diff --git a/tests/gtest/timeline_workarea_test.cpp b/tests/gtest/timeline_workarea_test.cpp
new file mode 100644
index 000000000..318f063b2
--- /dev/null
+++ b/tests/gtest/timeline_workarea_test.cpp
@@ -0,0 +1,55 @@
+#include <gtest/gtest.h>
+
+#include <QBuffer>
+#include <QXmlStreamReader>
+#include <QXmlStreamWriter>
+
+#include "timeline/timelineworkarea.h"
+
+TEST(TimelineWorkArea, DefaultsAndSetters)
+{
+	olive::TimelineWorkArea workarea;
+	EXPECT_FALSE(workarea.enabled());
+
+	olive::core::TimeRange range(olive::core::rational(5, 1),
+								 olive::core::rational(10, 1));
+	workarea.set_enabled(true);
+	workarea.set_range(range);
+
+	EXPECT_TRUE(workarea.enabled());
+	EXPECT_EQ(workarea.range(), range);
+	EXPECT_EQ(workarea.in(), range.in());
+	EXPECT_EQ(workarea.out(), range.out());
+	EXPECT_EQ(workarea.length(), range.length());
+}
+
+TEST(TimelineWorkArea, SaveLoadRoundTrip)
+{
+	olive::TimelineWorkArea workarea;
+	workarea.set_enabled(true);
+	workarea.set_range(olive::core::TimeRange(olive::core::rational(2, 1),
+											  olive::core::rational(6, 1)));
+
+	QByteArray xml;
+	QBuffer buffer(&xml);
+	ASSERT_TRUE(buffer.open(QIODevice::WriteOnly));
+	QXmlStreamWriter writer(&buffer);
+	writer.writeStartDocument();
+	writer.writeStartElement(QStringLiteral("workarea"));
+	workarea.save(&writer);
+	writer.writeEndElement();
+	writer.writeEndDocument();
+	buffer.close();
+
+	olive::TimelineWorkArea loaded;
+	QBuffer read_buffer(&xml);
+	ASSERT_TRUE(read_buffer.open(QIODevice::ReadOnly));
+	QXmlStreamReader reader(&read_buffer);
+	ASSERT_TRUE(reader.readNextStartElement());
+	EXPECT_TRUE(loaded.load(&reader));
+
+	EXPECT_TRUE(loaded.enabled());
+	EXPECT_EQ(loaded.range(),
+			  olive::core::TimeRange(olive::core::rational(2, 1),
+									 olive::core::rational(6, 1)));
+}