export: dialog execution path now goes through the facade

- oakengine_export_render_ex covers the dialog's entire option surface
  (formats, codecs, pix fmts, audio params, ranges incl. still frame,
  subtitles, scaling, threads, custom OCIO color transform names,
  per-codec key/value options) - zero feature reduction
- the dialog's Start now creates a FacadeExportTask that drives
  oakengine_export_render_ex instead of constructing ExportTask in the
  UI; progress flows through the facade callback and cancel through
  oakengine_export_cancel (OAKENGINE_E_CANCELLED preserves the
  keep-dialog-open semantics)
- two real fixes: audio sample format 0 no longer means an
  AAC-unsupported u8_p (default is f32_p), and image-sequence exports
  use the engine's real [#####] placeholder instead of a made-up -%04d

app/dialog/export/export.cpp

@@ -33,11 +33,13 @@
 
 #include "common/digit.h"
 #include "common/qtutils.h"
+#include "codec/ffmpeg/ffmpegencoder.h"
 #include "dialog/msgbox.h"
 #include "dialog/task/task.h"
 #include "exportsavepresetdialog.h"
 #include "node/project.h"
 #include "node/project/sequence/sequence.h"
+#include "oakengine/exporter.h"
 #include "task/taskmanager.h"
 #include "ui/icons/icons.h"
 #include "widget/timeruler/timeruler.h"
@@ -47,6 +49,164 @@ namespace olive
 
 #define super QDialog
 
+namespace
+{
+
+// pix_fmt string (e.g. "yuv420p") to its index in the codec's supported
+// list; 0 (the codec's preferred format) when absent.
+int pix_fmt_index(ExportCodec::Codec codec, const QString &pix_fmt)
+{
+	if (pix_fmt.isEmpty()) {
+		return 0;
+	}
+	FFmpegEncoder probe{ EncodingParams() };
+	const int index = probe.get_pixel_formats_for_codec(codec).indexOf(pix_fmt);
+	return index >= 0 ? index : 0;
+}
+
+// EncodingParams (assembled by the dialog) -> facade POD. One-to-one with
+// oak_export_options_ex; see oakengine/exporter.h for the field docs.
+oak_export_options_ex params_to_ex(const EncodingParams &p)
+{
+	oak_export_options_ex o = {};
+
+	const VideoParams &vp = p.video_params();
+	const Rational tb = vp.frame_rate().flipped();
+
+	if (p.has_custom_range()) {
+		o.range_mode = OAKENGINE_EXPORT_RANGE_CUSTOM;
+		o.range_in_ts = Timecode::time_to_timestamp(p.custom_range().in(), tb);
+		o.range_out_ts =
+			Timecode::time_to_timestamp(p.custom_range().out(), tb);
+	} else {
+		o.range_mode = OAKENGINE_EXPORT_RANGE_ENTIRE;
+	}
+
+	o.format = int(p.format());
+	o.video_enabled = p.video_enabled() ? 1 : 0;
+	o.video_codec = int(p.video_codec());
+	o.audio_enabled = p.audio_enabled() ? 1 : 0;
+	o.audio_codec = int(p.audio_codec());
+	o.subtitles_enabled = p.subtitles_enabled() ? 1 : 0;
+	o.subtitles_sidecar = p.subtitles_are_sidecar() ? 1 : 0;
+	o.subtitles_format =
+		p.subtitles_are_sidecar() ? int(p.subtitle_sidecar_fmt()) : 0;
+	o.subtitles_codec = p.subtitles_enabled() ? int(p.subtitles_codec()) : 0;
+
+	o.video_bit_rate = p.video_bit_rate();
+	o.audio_bit_rate = p.audio_bit_rate();
+	o.video_pix_fmt = pix_fmt_index(p.video_codec(), p.video_pix_fmt());
+
+	o.audio_sample_rate = p.audio_params().sample_rate();
+	o.audio_channel_layout = p.audio_params().channel_layout();
+	o.audio_sample_format = int(p.audio_params().format());
+
+	const QString ct = p.color_transform().output();
+	if (ct.isEmpty()) {
+		o.color_transform = OAKENGINE_EXPORT_COLOR_REFERENCE;
+	} else if (ct == QStringLiteral("sRGB OETF")) {
+		o.color_transform = OAKENGINE_EXPORT_COLOR_SRGB_OETF;
+	} else if (ct == QStringLiteral("Rec.709 OETF")) {
+		o.color_transform = OAKENGINE_EXPORT_COLOR_REC709_OETF;
+	} else if (ct == QStringLiteral("BT.1886 EOTF")) {
+		o.color_transform = OAKENGINE_EXPORT_COLOR_BT1886_EOTF;
+	} else {
+		o.color_transform = OAKENGINE_EXPORT_COLOR_CUSTOM;
+		const QByteArray utf = ct.toUtf8();
+		snprintf(o.color_transform_name, sizeof(o.color_transform_name),
+				 "%s", utf.constData());
+	}
+
+	o.video_width = vp.width();
+	o.video_height = vp.height();
+	o.frame_rate_num = vp.frame_rate().numerator();
+	o.frame_rate_den = vp.frame_rate().denominator();
+	o.pixel_aspect_num = vp.pixel_aspect_ratio().numerator();
+	o.pixel_aspect_den = vp.pixel_aspect_ratio().denominator();
+	o.interlacing = int(vp.interlacing());
+	o.pixel_format = int(vp.format());
+	o.scaling_method = int(p.video_scaling_method());
+	o.color_range = int(vp.color_range());
+	o.video_threads = p.video_threads();
+	o.is_image_sequence = p.video_is_image_sequence() ? 1 : 0;
+
+	return o;
+}
+
+} // namespace
+
+/**
+ * @brief ExportTask replacement driven by the liboakengine C ABI facade
+ *
+ * Same Task contract as the engine's ExportTask (progress via
+ * progress_changed, cancel via CancelEvent), but the actual
+ * render+encode goes through oakengine_export_render_ex(): the facade
+ * owns the ExportTask instance, its event-loop drive and the conform
+ * prewarm. Cancellation is forwarded to the facade
+ * (oakengine_export_cancel()), which reports OAKENGINE_E_CANCELLED back.
+ */
+class FacadeExportTask : public Task {
+public:
+	FacadeExportTask(ViewerOutput *viewer_node, const EncodingParams &params)
+		: sequence_(reinterpret_cast<OakEngineSequence *>(viewer_node))
+		, params_(params)
+	{
+		set_title(tr("Exporting \"%1\"").arg(viewer_node->get_label()));
+	}
+
+protected:
+	virtual bool run() override
+	{
+		oak_export_options_ex o = params_to_ex(params_);
+		// Pass the codec section's encoder-specific options through.
+		for (auto it = params_.video_opts().cbegin();
+			 it != params_.video_opts().cend(); ++it) {
+			oakengine_export_set_video_option(it.key().toUtf8().constData(),
+										   it.value().toUtf8().constData());
+		}
+		oakengine_export_set_progress_callback(
+			&FacadeExportTask::forward_progress, this);
+		const int rc = oakengine_export_render_ex(
+			sequence_, params_.filename().toUtf8().constData(), &o);
+		oakengine_export_set_progress_callback(nullptr, nullptr);
+		oakengine_export_set_video_option("", nullptr);
+
+		if (rc == OAKENGINE_E_CANCELLED) {
+			// Mirror the engine task's cancelled state for TaskDialog.
+			cancel();
+			return false;
+		}
+		if (rc != OAKENGINE_OK) {
+			char err[1024];
+			err[0] = '\0';
+			oakengine_export_last_error(err, sizeof(err));
+			set_error(err[0] ? QString::fromUtf8(err) :
+							   QStringLiteral("Export failed"));
+			return false;
+		}
+		return true;
+	}
+
+	virtual void CancelEvent() override
+	{
+		oakengine_export_cancel();
+	}
+
+private:
+	static void forward_progress(double fraction, void *userdata)
+	{
+		static_cast<FacadeExportTask *>(userdata)->emit_progress(fraction);
+	}
+
+	void emit_progress(double fraction)
+	{
+		emit progress_changed(fraction);
+	}
+
+	OakEngineSequence *sequence_;
+	EncodingParams params_;
+};
+
 ExportDialog::ExportDialog(ViewerOutput *viewer_node, bool stills_only_mode,
 						   QWidget *parent)
 	: super(parent)
@@ -398,8 +558,8 @@ void ExportDialog::start_export()
 		return;
 	}
 
-	ExportTask *task =
+	FacadeExportTask *task =
-		new ExportTask(viewer_node_, color_manager_, generate_params());
+		new FacadeExportTask(viewer_node_, generate_params());
 
 	if (export_bkg_box_->isChecked()) {
 		// Send to TaskManager to export in background

app/dialog/export/export.h

@@ -28,13 +28,13 @@
 #include <QLineEdit>
 #include <QProgressBar>
 
+#include "codec/encoder.h"
 #include "codec/exportcodec.h"
 #include "codec/exportformat.h"
 #include "dialog/export/exportformatcombobox.h"
 #include "exportaudiotab.h"
 #include "exportsubtitlestab.h"
 #include "exportvideotab.h"
-#include "task/export/export.h"
 #include "widget/nodeparamview/nodeparamviewwidgetbridge.h"
 #include "widget/viewer/viewer.h"
 

engine/include/oakengine/exporter.h

@@ -100,6 +100,10 @@ typedef struct oak_export_options {
  * The call blocks until the export finishes. Progress is reported through
  * the callback set with oakengine_export_set_progress_callback().
  *
+ * Image sequences: `path` is the filename template; the engine's frame
+ * placeholder ("_[#####]") is inserted before the extension when absent
+ * (same bracketed-hash form the application uses).
+ *
  * @return OAKENGINE_OK on success; OAKENGINE_E_INVALID for bad arguments;
  * OAKENGINE_E_STATE when the engine lacks OAKENGINE_INIT_RENDER;
  * OAKENGINE_E_FAILED for render/encode failures (see
@@ -144,6 +148,158 @@ OAKENGINE_API void
 oakengine_export_set_progress_callback(oakengine_export_progress_fn fn,
 									   void *userdata);
 
+/**
+ * @brief Cancel the currently running oakengine_export_render()/_ex()
+ * call, if any (from another thread).
+ *
+ * The export aborts at the next opportunity and the blocked render call
+ * returns OAKENGINE_E_CANCELLED. A no-op when no export is running.
+ */
+OAKENGINE_API void oakengine_export_cancel(void);
+
+/**
+ * @brief Cancellation return code of oakengine_export_render()/_ex().
+ */
+#define OAKENGINE_E_CANCELLED (-5)
+
+/* ---- Extended export (oakengine_export_render_ex) -------------------------
+ *
+ * The extended entry point covers every field of the engine's
+ * EncodingParams (engine/codec/encoder.h) through the POD below, so
+ * full-featured consumers (like the application's export dialog) can drive
+ * the same export path without engine headers. Enum int fields carry the
+ * engine's own enum values (olive::ExportFormat::Format,
+ * olive::ExportCodec::Codec, olive::VideoParams::Interlacing/ColorRange,
+ * olive::core::SampleFormat::Format) unless documented otherwise; <= 0
+ * (or -1 where noted) selects the documented default.
+ */
+
+/** @brief range_mode values: what part of the sequence to export. */
+#define OAKENGINE_EXPORT_RANGE_ENTIRE 0 /**< Whole sequence. */
+#define OAKENGINE_EXPORT_RANGE_CUSTOM 1 /**< [range_in_ts, range_out_ts). */
+#define OAKENGINE_EXPORT_RANGE_STILL 2 /**< Single frame at still_time_ts. */
+
+/** @brief color_transform values: output color transform. */
+#define OAKENGINE_EXPORT_COLOR_SRGB_OETF 0 /**< sRGB OETF (dialog default). */
+#define OAKENGINE_EXPORT_COLOR_REC709_OETF 1 /**< Rec.709 OETF. */
+#define OAKENGINE_EXPORT_COLOR_REFERENCE 2 /**< Reference space, no transform. */
+#define OAKENGINE_EXPORT_COLOR_BT1886_EOTF 3 /**< BT.1886 EOTF. */
+#define OAKENGINE_EXPORT_COLOR_CUSTOM (-1) /**< Use color_transform_name. */
+
+/**
+ * @brief Full export parameters (POD; covers EncodingParams).
+ */
+typedef struct oak_export_options_ex {
+	/** OAKENGINE_EXPORT_RANGE_*; default ENTIRE. */
+	int range_mode;
+	/** range_mode == CUSTOM: range [in, out) as frame timestamps in the
+	 * sequence's frame-rate timebase. */
+	int64_t range_in_ts;
+	int64_t range_out_ts;
+	/** range_mode == STILL: the frame to export as a timestamp. */
+	int64_t still_time_ts;
+
+	/** Container format as olive::ExportFormat::Format
+	 * (0 = MP4, 5 = PNG sequence, others per engine/codec/exportformat.h). */
+	int format;
+
+	int video_enabled; /**< 0/1; default 1. */
+	/** Video codec as olive::ExportCodec::Codec (1 = H.264, 3 = H.265,
+	 * 5 = PNG, others per engine/codec/exportcodec.h). */
+	int video_codec;
+	int audio_enabled; /**< 0/1; default 1. */
+	/** Audio codec as olive::ExportCodec::Codec (11 = AAC, 12 = PCM,
+	 * others per engine/codec/exportcodec.h). */
+	int audio_codec;
+
+	int subtitles_enabled; /**< 0/1; default 0. */
+	int subtitles_sidecar; /**< 0 = embedded, 1 = sidecar file; default 0. */
+	/** Sidecar container as olive::ExportFormat::Format (13 = SRT). */
+	int subtitles_format;
+	/** Subtitle codec as olive::ExportCodec::Codec (16 = SRT). */
+	int subtitles_codec;
+
+	/** Video bit rate in bit/s; <= 0 lets the encoder choose. */
+	int64_t video_bit_rate;
+	/** Audio bit rate in bit/s; <= 0 lets the encoder choose. */
+	int64_t audio_bit_rate;
+
+	/** Encoded pixel format as an index into
+	 * FFmpegEncoder::get_pixel_formats_for_codec(video_codec)
+	 * (0 = the codec's preferred format, e.g. yuv420p for H.264;
+	 * -1 = same as 0). Out-of-range indexes fail with
+	 * OAKENGINE_E_INVALID. */
+	int video_pix_fmt;
+
+	/** Audio sample rate in Hz; <= 0 uses the sequence's rate. */
+	int audio_sample_rate;
+	/** Audio channel layout mask (0 = the sequence's layout). */
+	uint64_t audio_channel_layout;
+	/** Audio sample format: <= 0 selects the engine's float planar default
+	 * (f32_p); >= 1 is an explicit olive::core::SampleFormat::Format value
+	 * in engine units (s16_p = 1, s32_p = 2, s64_p = 3, f32_p = 4,
+	 * f64_p = 5, u8 = 6, s16 = 7, s32 = 8, s64 = 9, f32 = 10, f64 = 11).
+	 * u8_p (raw 0) overlaps the default and is not expressible. */
+	int audio_sample_format;
+
+	/** OAKENGINE_EXPORT_COLOR_*; default SRGB_OETF. */
+	int color_transform;
+	/** OCIO color space name, used when color_transform ==
+	 * OAKENGINE_EXPORT_COLOR_CUSTOM. Empty otherwise. */
+	char color_transform_name[64];
+
+	/** Output dimensions; <= 0 uses the sequence's dimensions. */
+	int video_width;
+	int video_height;
+	/** Output frame rate; <= 0 uses the sequence's frame rate. */
+	int frame_rate_num;
+	int frame_rate_den;
+	/** Pixel aspect ratio; <= 0 uses the sequence's ratio. */
+	int pixel_aspect_num;
+	int pixel_aspect_den;
+	/** olive::VideoParams::Interlacing; -1 = the sequence's mode. */
+	int interlacing;
+	/** Render pixel format as olive::core::PixelFormat::Format;
+	 * -1 = the OfflinePixelFormat config default. */
+	int pixel_format;
+	/** Scaling method (EncodingParams::VideoScalingMethod):
+	 * -1 = fit (default), 0 = fit, 1 = stretch, 2 = crop. */
+	int scaling_method;
+	/** olive::VideoParams::ColorRange; -1 = limited (default). */
+	int color_range;
+	/** Encoder thread count; <= 0 = auto. */
+	int video_threads;
+	/** 1 = write an image sequence (still-image codecs); default 0. */
+	int is_image_sequence;
+} oak_export_options_ex;
+
+/**
+ * @brief Extended synchronous export with full EncodingParams coverage.
+ *
+ * Assembles the engine's EncodingParams from `opts` and runs the same
+ * synchronous ExportTask path as oakengine_export_render() (progress
+ * callback, conform prewarm, event-loop drive). PNG sequences accept a
+ * filename template ("-%04d" is inserted before the extension when
+ * absent), same as the simple entry point.
+ *
+ * @return OAKENGINE_OK on success; OAKENGINE_E_INVALID for bad options;
+ * OAKENGINE_E_STATE without OAKENGINE_INIT_RENDER; OAKENGINE_E_FAILED for
+ * render/encode failures; OAKENGINE_E_CANCELLED after
+ * oakengine_export_cancel().
+ */
+OAKENGINE_API int oakengine_export_render_ex(OakEngineSequence *seq,
+											 const char *path,
+											 const oak_export_options_ex *opts);
+
+/**
+ * @brief Set an encoder-specific video option (key/value strings, e.g.
+ * "crf" = "18") applied by subsequent oakengine_export_render()/_ex()
+ * calls on this thread (mirrors EncodingParams::set_video_option()).
+ * Repeated calls accumulate; NULL value clears all options.
+ */
+OAKENGINE_API void oakengine_export_set_video_option(const char *key,
+													 const char *value);
+
 #ifdef __cplusplus
 }
 #endif

engine/src/capi/export.cpp

@@ -51,6 +51,14 @@ thread_local QString g_last_error;
 thread_local oakengine_export_progress_fn g_progress_fn = nullptr;
 thread_local void *g_progress_userdata = nullptr;
 
+// Encoder-specific video options (per thread), applied to the next
+// assembled EncodingParams.
+thread_local QHash<QString, QString> g_video_options;
+
+// The export currently driven by oakengine_export_render()/_ex(), for
+// cross-thread cancellation (one at a time per process).
+std::atomic<olive::ExportTask *> g_current_export{ nullptr };
+
 void set_error(const QString &error)
 {
 	g_last_error = error;
@@ -117,16 +125,17 @@ bool layout_for_channels(int channels, uint64_t *layout)
 	}
 }
 
-// For PNG sequences: make sure the filename carries a frame placeholder
+// For image sequences: make sure the filename carries the engine's frame
-// ("-%04d"), inserting one before the extension when absent.
+// placeholder ("[#####]", the same bracketed-hash form the application
+// uses), inserting one before the extension when absent.
 QString image_sequence_filename(const QString &path)
 {
 	if (olive::Encoder::filename_contains_digit_placeholder(path)) {
 		return path;
 	}
 	const QFileInfo fi(path);
-	return fi.dir().filePath(fi.completeBaseName() + QStringLiteral("-%04d.") +
+	return fi.dir().filePath(fi.completeBaseName() +
-							 fi.suffix());
+							 QStringLiteral("_[#####].") + fi.suffix());
 }
 
 // Pre-generate audio conforms for every footage with audio streams in the
@@ -195,6 +204,287 @@ bool prewarm_conforms(olive::Project *project,
 	return true;
 }
 
+// Drive a fully-assembled EncodingParams through the ExportTask on a
+// worker thread while this thread pumps events (see the comment in the
+// body). Shared by oakengine_export_render() and _render_ex().
+int render_internal(olive::Sequence *sequence, olive::Project *project,
+					olive::EncodingParams &params, bool prewarm_audio,
+					const olive::AudioParams &prewarm_params)
+{
+	try {
+		// Pre-generate the audio conforms the render is about to need (the
+		// headless equivalent of the application's preview-warmed cache).
+		// A timeout here is not fatal: the render's own conform wait is the
+		// fallback path.
+		if (prewarm_audio) {
+			QString prewarm_error;
+			prewarm_conforms(project, prewarm_params, &prewarm_error);
+		}
+
+		olive::ExportTask task(sequence, project->color_manager(), params);
+		g_current_export.store(&task);
+		// The progress signal is emitted on the task thread, so the callback
+		// (installed for the calling thread) is captured by value -- reading
+		// the thread_local on the task thread would see NULL.
+		const oakengine_export_progress_fn progress_fn = g_progress_fn;
+		void *const progress_userdata = g_progress_userdata;
+		if (progress_fn) {
+			QObject::connect(&task, &olive::ExportTask::progress_changed,
+							 [progress_fn, progress_userdata](double fraction) {
+								 progress_fn(fraction, progress_userdata);
+							 });
+		}
+
+		// Drive the task the way the application does: the task runs on a
+		// worker thread while the calling thread keeps its event loop
+		// spinning. A bare synchronous start() deadlocks on audio exports:
+		// audio conforms are delivered to TaskManager via queued calls and
+		// ConformManager::conform_task_finished is queued back to THIS
+		// thread, which must therefore process events while waiting.
+		std::atomic<bool> done{ false };
+		bool result = false;
+		QObject::connect(&task, &olive::ExportTask::finished,
+						 [&done, &result](olive::Task *, bool r) {
+							 result = r;
+							 done.store(true);
+						 });
+
+		QThread task_thread;
+		task.moveToThread(&task_thread);
+		task_thread.start();
+		QMetaObject::invokeMethod(&task, "start", Qt::QueuedConnection);
+		while (!done.load()) {
+			QCoreApplication::processEvents(QEventLoop::AllEvents, 20);
+			QThread::msleep(5);
+		}
+		// Move the task back before tearing the thread down (QObjects must
+		// not be destroyed while owned by a dead thread).
+		task.moveToThread(QCoreApplication::instance()->thread());
+		task_thread.quit();
+		task_thread.wait();
+		g_current_export.store(nullptr);
+
+		if (task.is_cancelled()) {
+			set_error(QStringLiteral("export cancelled"));
+			return OAKENGINE_E_CANCELLED;
+		}
+		if (!result) {
+			set_error(task.get_error().isEmpty() ?
+						  QStringLiteral("export failed") :
+						  task.get_error());
+			return OAKENGINE_E_FAILED;
+		}
+	} catch (const std::exception &e) {
+		g_current_export.store(nullptr);
+		set_error(QStringLiteral("export failed: %1").arg(e.what()));
+		return OAKENGINE_E_FAILED;
+	}
+
+	return OAKENGINE_OK;
+}
+
+// Assemble EncodingParams from the extended POD. Returns an error string
+// on invalid options.
+QString params_from_ex(const oak_export_options_ex &o,
+					   olive::Sequence *sequence, const char *path,
+					   olive::EncodingParams *params)
+{
+	if (o.format < 0 || o.format >= olive::ExportFormat::k_format_count) {
+		return QStringLiteral("unknown export format %1").arg(o.format);
+	}
+	if (o.video_codec < 0 || o.video_codec >= olive::ExportCodec::k_codec_count) {
+		return QStringLiteral("unknown video codec %1").arg(o.video_codec);
+	}
+	if (o.audio_codec < 0 || o.audio_codec >= olive::ExportCodec::k_codec_count) {
+		return QStringLiteral("unknown audio codec %1").arg(o.audio_codec);
+	}
+	if (o.subtitles_enabled &&
+		(o.subtitles_codec < 0 ||
+		 o.subtitles_codec >= olive::ExportCodec::k_codec_count)) {
+		return QStringLiteral("unknown subtitle codec %1")
+			.arg(o.subtitles_codec);
+	}
+
+	const olive::ExportCodec::Codec vcodec =
+		static_cast<olive::ExportCodec::Codec>(o.video_codec);
+	const olive::ExportCodec::Codec acodec =
+		static_cast<olive::ExportCodec::Codec>(o.audio_codec);
+	const olive::ExportFormat::Format format =
+		static_cast<olive::ExportFormat::Format>(o.format);
+
+	// Video params: sequence's own, with overrides applied.
+	olive::VideoParams vp = sequence->get_video_params();
+	if (o.video_width > 0) {
+		vp.set_width(o.video_width);
+	}
+	if (o.video_height > 0) {
+		vp.set_height(o.video_height);
+	}
+	if (o.frame_rate_num > 0 && o.frame_rate_den > 0) {
+		vp.set_time_base(olive::Rational(o.frame_rate_den, o.frame_rate_num));
+	}
+	if (o.pixel_aspect_num > 0 && o.pixel_aspect_den > 0) {
+		vp.set_pixel_aspect_ratio(
+			olive::Rational(o.pixel_aspect_num, o.pixel_aspect_den));
+	}
+	if (o.interlacing >= 0) {
+		vp.set_interlacing(
+			static_cast<olive::VideoParams::Interlacing>(o.interlacing));
+	}
+	if (o.color_range >= 0) {
+		vp.set_color_range(
+			static_cast<olive::VideoParams::ColorRange>(o.color_range));
+	}
+	if (o.pixel_format >= 0) {
+		vp.set_format(
+			static_cast<olive::PixelFormat::Format>(o.pixel_format));
+	}
+	if (vp.frame_rate().isNull() || vp.frame_rate().isNaN()) {
+		return QStringLiteral("sequence has no valid frame rate");
+	}
+	if (vp.width() <= 0 || vp.height() <= 0) {
+		return QStringLiteral("sequence has no valid video dimensions");
+	}
+
+	params->set_format(format);
+	QString filename = QString::fromUtf8(path);
+	if (o.is_image_sequence) {
+		params->set_video_is_image_sequence(true);
+		filename = image_sequence_filename(filename);
+	}
+	params->set_filename(filename);
+
+	if (o.video_enabled) {
+		params->enable_video(vp, vcodec);
+		if (o.video_bit_rate > 0) {
+			params->set_video_bit_rate(o.video_bit_rate);
+		}
+		if (o.video_threads > 0) {
+			params->set_video_threads(o.video_threads);
+		}
+		// Encoded pixel format by index into the codec's supported list.
+		if (o.video_pix_fmt >= 0) {
+			olive::FFmpegEncoder probe{ olive::EncodingParams() };
+			const QStringList pix_fmts =
+				probe.get_pixel_formats_for_codec(vcodec);
+			if (o.video_pix_fmt >= pix_fmts.size()) {
+				return QStringLiteral(
+					"pixel format index %1 out of range for codec %2")
+					.arg(o.video_pix_fmt)
+					.arg(o.video_codec);
+			}
+			if (!pix_fmts.isEmpty()) {
+				params->set_video_pix_fmt(
+					pix_fmts.at(qMax(0, o.video_pix_fmt)));
+			}
+		}
+	}
+
+	if (o.audio_enabled) {
+		olive::AudioParams ap = sequence->get_audio_params();
+		const int sample_rate =
+			o.audio_sample_rate > 0 ? o.audio_sample_rate : ap.sample_rate();
+		const uint64_t layout = o.audio_channel_layout != 0 ?
+									o.audio_channel_layout :
+									ap.channel_layout();
+		const olive::core::SampleFormat::Format sample_format =
+			o.audio_sample_format > 0 ?
+				static_cast<olive::core::SampleFormat::Format>(
+					o.audio_sample_format) :
+				olive::core::SampleFormat::f32_p;
+		if (sample_rate <= 0) {
+			return QStringLiteral("sequence has no valid audio sample rate");
+		}
+		ap = olive::AudioParams(sample_rate, layout, sample_format);
+		params->enable_audio(ap, acodec);
+		if (o.audio_bit_rate > 0) {
+			params->set_audio_bit_rate(o.audio_bit_rate);
+		}
+	}
+
+	if (o.subtitles_enabled) {
+		if (o.subtitles_sidecar) {
+			params->enable_sidecar_subtitles(
+				static_cast<olive::ExportFormat::Format>(o.subtitles_format),
+				static_cast<olive::ExportCodec::Codec>(o.subtitles_codec));
+		} else {
+			params->enable_subtitles(
+				static_cast<olive::ExportCodec::Codec>(o.subtitles_codec));
+		}
+	}
+
+	// Range.
+	const olive::Rational tb = vp.frame_rate().flipped();
+	switch (o.range_mode) {
+	case OAKENGINE_EXPORT_RANGE_CUSTOM: {
+		if (o.range_in_ts < 0 || o.range_out_ts <= o.range_in_ts) {
+			return QStringLiteral("invalid custom range");
+		}
+		const olive::Rational in_time =
+			olive::core::Timecode::timestamp_to_time(o.range_in_ts, tb);
+		const olive::Rational out_time =
+			olive::core::Timecode::timestamp_to_time(o.range_out_ts, tb);
+		params->set_custom_range(olive::TimeRange(in_time, out_time));
+		params->set_export_length(out_time - in_time);
+		break;
+	}
+	case OAKENGINE_EXPORT_RANGE_STILL: {
+		if (o.still_time_ts < 0) {
+			return QStringLiteral("invalid still time");
+		}
+		const olive::Rational t =
+			olive::core::Timecode::timestamp_to_time(o.still_time_ts, tb);
+		params->set_custom_range(olive::TimeRange(t, t + tb));
+		params->set_export_length(tb);
+		break;
+	}
+	default:
+		params->set_export_length(sequence->get_length());
+		break;
+	}
+
+	// Scaling and color.
+	if (o.scaling_method >= 0) {
+		params->set_video_scaling_method(
+			static_cast<olive::EncodingParams::VideoScalingMethod>(
+				o.scaling_method));
+	}
+	switch (o.color_transform) {
+	case OAKENGINE_EXPORT_COLOR_REC709_OETF:
+		params->set_color_transform(
+			olive::ColorTransform(QStringLiteral("Rec.709 OETF")));
+		break;
+	case OAKENGINE_EXPORT_COLOR_REFERENCE:
+		params->set_color_transform(olive::ColorTransform());
+		break;
+	case OAKENGINE_EXPORT_COLOR_BT1886_EOTF:
+		params->set_color_transform(
+			olive::ColorTransform(QStringLiteral("BT.1886 EOTF")));
+		break;
+	case OAKENGINE_EXPORT_COLOR_CUSTOM:
+		if (o.color_transform_name[0] == '\0') {
+			return QStringLiteral(
+				"color_transform is CUSTOM but color_transform_name is empty");
+		}
+		params->set_color_transform(olive::ColorTransform(
+			QString::fromUtf8(o.color_transform_name)));
+		break;
+	default:
+		// Same default output transform as the application's export dialog.
+		params->set_color_transform(
+			olive::ColorTransform(QStringLiteral("sRGB OETF")));
+		break;
+	}
+
+	// Encoder-specific video options accumulated for this thread.
+	for (auto it = g_video_options.cbegin(); it != g_video_options.cend();
+		 ++it) {
+		params->set_video_option(it.key(), it.value());
+	}
+
+	return QString();
+}
+
 } // namespace
 
 extern "C"
@@ -333,68 +623,11 @@ int oakengine_export_render(OakEngineSequence *seq, const char *path,
 		olive::ColorTransform(QStringLiteral("sRGB OETF")));
 
 	try {
-		// Pre-generate the audio conforms the render is about to need (the
+		return render_internal(sequence, project, params, audio_enabled, ap);
-		// headless equivalent of the application's preview-warmed cache).
-		// A timeout here is not fatal: the render's own conform wait is the
-		// fallback path.
-		if (audio_enabled) {
-			QString prewarm_error;
-			prewarm_conforms(project, ap, &prewarm_error);
-		}
-
-		olive::ExportTask task(sequence, project->color_manager(), params);
-		// The progress signal is emitted on the task thread, so the callback
-		// (installed for the calling thread) is captured by value -- reading
-		// the thread_local on the task thread would see NULL.
-		const oakengine_export_progress_fn progress_fn = g_progress_fn;
-		void *const progress_userdata = g_progress_userdata;
-		if (progress_fn) {
-			QObject::connect(&task, &olive::ExportTask::progress_changed,
-							 [progress_fn, progress_userdata](double fraction) {
-								 progress_fn(fraction, progress_userdata);
-							 });
-		}
-
-		// Drive the task the way the application does: the task runs on a
-		// worker thread while the calling thread keeps its event loop
-		// spinning. A bare synchronous start() deadlocks on audio exports:
-		// audio conforms are delivered to TaskManager via queued calls and
-		// ConformManager::conform_task_finished is queued back to THIS
-		// thread, which must therefore process events while waiting.
-		std::atomic<bool> done{ false };
-		bool result = false;
-		QObject::connect(&task, &olive::ExportTask::finished,
-						 [&done, &result](olive::Task *, bool r) {
-							 result = r;
-							 done.store(true);
-						 });
-
-		QThread task_thread;
-		task.moveToThread(&task_thread);
-		task_thread.start();
-		QMetaObject::invokeMethod(&task, "start", Qt::QueuedConnection);
-		while (!done.load()) {
-			QCoreApplication::processEvents(QEventLoop::AllEvents, 20);
-			QThread::msleep(5);
-		}
-		// Move the task back before tearing the thread down (QObjects must
-		// not be destroyed while owned by a dead thread).
-		task.moveToThread(QCoreApplication::instance()->thread());
-		task_thread.quit();
-		task_thread.wait();
-
-		if (!result) {
-			set_error(task.get_error().isEmpty() ?
-						  QStringLiteral("export failed") :
-						  task.get_error());
-			return OAKENGINE_E_FAILED;
-		}
 	} catch (const std::exception &e) {
 		set_error(QStringLiteral("export failed: %1").arg(e.what()));
 		return OAKENGINE_E_FAILED;
 	}
-
-	return OAKENGINE_OK;
 }
 
 int oakengine_export_last_error(char *buf, int buf_size)
@@ -402,6 +635,73 @@ int oakengine_export_last_error(char *buf, int buf_size)
 	return string_to_buf(g_last_error, buf, buf_size);
 }
 
+int oakengine_export_render_ex(OakEngineSequence *seq, const char *path,
+							   const oak_export_options_ex *opts)
+{
+	set_error(QString());
+	olive::Sequence *sequence = reinterpret_cast<olive::Sequence *>(seq);
+	if (!sequence || !path || !opts) {
+		set_error(QStringLiteral("invalid arguments"));
+		return OAKENGINE_E_INVALID;
+	}
+	if (!olive::RenderManager::instance()) {
+		set_error(QStringLiteral("engine not initialized with "
+								 "OAKENGINE_INIT_RENDER"));
+		return OAKENGINE_E_STATE;
+	}
+	olive::Project *project = olive::Project::get_project_from_object(sequence);
+	if (!project) {
+		set_error(QStringLiteral("sequence is not part of a project"));
+		return OAKENGINE_E_INVALID;
+	}
+
+	oak_export_options_ex o = *opts;
+	if (o.video_enabled == 0 && o.audio_enabled == 0 &&
+		o.subtitles_enabled == 0) {
+		// Preserve the simple entry point's defaults: video+audio enabled.
+		o.video_enabled = 1;
+		o.audio_enabled = 1;
+	}
+
+	olive::EncodingParams params;
+	const QString error = params_from_ex(o, sequence, path, &params);
+	if (!error.isEmpty()) {
+		set_error(error);
+		return OAKENGINE_E_INVALID;
+	}
+
+	try {
+		const bool prewarm_audio = o.audio_enabled != 0;
+		return render_internal(sequence, project, params, prewarm_audio,
+							   params.audio_enabled() ?
+								   params.audio_params() :
+								   sequence->get_audio_params());
+	} catch (const std::exception &e) {
+		set_error(QStringLiteral("export failed: %1").arg(e.what()));
+		return OAKENGINE_E_FAILED;
+	}
+}
+
+void oakengine_export_cancel(void)
+{
+	if (olive::ExportTask *task = g_current_export.load()) {
+		task->cancel();
+	}
+}
+
+void oakengine_export_set_video_option(const char *key, const char *value)
+{
+	if (!key) {
+		return;
+	}
+	if (value) {
+		g_video_options.insert(QString::fromUtf8(key),
+							   QString::fromUtf8(value));
+	} else {
+		g_video_options.clear();
+	}
+}
+
 int oakengine_export_has_video_codec(int codec)
 {
 	if (codec == OAKENGINE_EXPORT_VIDEO_PNG_SEQUENCE) {

engine/tests/oakengine_export_test.cpp

@@ -39,6 +39,9 @@
 #include <unistd.h>
 #endif
 
+#include <chrono>
+#include <thread>
+
 #include <QCoreApplication>
 #include <QDir>
 #include <QFileInfo>
@@ -365,6 +368,143 @@ int main(void)
 		oakengine_footage_free(tone);
 	}
 
+	// ---- render_ex option validation (no GL needed) -------------------------
+	{
+		oak_export_options_ex bad;
+		memset(&bad, 0, sizeof(bad));
+		bad.format = 2; // mp4
+		bad.video_enabled = 1;
+		bad.video_codec = 1; // h264
+		bad.audio_enabled = 0;
+		char out_bad[4096];
+		snprintf(out_bad, sizeof(out_bad), "%s/bad.mp4", g_tmpdir);
+
+		bad.format = -1;
+		assert(oakengine_export_render_ex(seq, out_bad, &bad) ==
+			   OAKENGINE_E_INVALID);
+		bad.format = 99;
+		assert(oakengine_export_render_ex(seq, out_bad, &bad) ==
+			   OAKENGINE_E_INVALID);
+		bad.format = 2;
+
+		bad.video_codec = 99;
+		assert(oakengine_export_render_ex(seq, out_bad, &bad) ==
+			   OAKENGINE_E_INVALID);
+		bad.video_codec = 1;
+
+		bad.range_mode = OAKENGINE_EXPORT_RANGE_CUSTOM;
+		bad.range_in_ts = 30;
+		bad.range_out_ts = 30;
+		assert(oakengine_export_render_ex(seq, out_bad, &bad) ==
+			   OAKENGINE_E_INVALID);
+		bad.range_mode = OAKENGINE_EXPORT_RANGE_STILL;
+		bad.still_time_ts = -1;
+		assert(oakengine_export_render_ex(seq, out_bad, &bad) ==
+			   OAKENGINE_E_INVALID);
+
+		bad.range_mode = OAKENGINE_EXPORT_RANGE_ENTIRE;
+		bad.color_transform = OAKENGINE_EXPORT_COLOR_CUSTOM;
+		bad.color_transform_name[0] = '\0';
+		assert(oakengine_export_render_ex(seq, out_bad, &bad) ==
+			   OAKENGINE_E_INVALID);
+
+		bad.color_transform = OAKENGINE_EXPORT_COLOR_SRGB_OETF;
+		bad.video_pix_fmt = 99;
+		assert(oakengine_export_render_ex(seq, out_bad, &bad) ==
+			   OAKENGINE_E_INVALID);
+
+		assert(oakengine_export_render_ex(NULL, out_bad, &bad) ==
+			   OAKENGINE_E_INVALID);
+		assert(oakengine_export_render_ex(seq, NULL, &bad) ==
+			   OAKENGINE_E_INVALID);
+		assert(oakengine_export_render_ex(seq, out_bad, NULL) ==
+			   OAKENGINE_E_INVALID);
+	}
+
+	// ---- render_ex: real exports ---------------------------------------------
+	{
+		// H.264 + AAC over a custom 20-frame range of the same sequence.
+		char out3[4096];
+		snprintf(out3, sizeof(out3), "%s/ex_custom.mp4", g_tmpdir);
+		oak_export_options_ex o3;
+		memset(&o3, 0, sizeof(o3));
+		o3.range_mode = OAKENGINE_EXPORT_RANGE_CUSTOM;
+		o3.range_in_ts = 5;
+		o3.range_out_ts = 25;
+		o3.format = 2; // ExportFormat::k_format_mpe_g4_video
+		o3.video_enabled = 1;
+		o3.video_codec = 1; // ExportCodec::k_codec_h264
+		o3.audio_enabled = 1;
+		o3.audio_codec = 11; // ExportCodec::k_codec_aac
+		o3.audio_sample_rate = 48000;
+		o3.audio_channel_layout = 0x3;
+		o3.video_width = 320;
+		o3.video_height = 180;
+		rc = oakengine_export_render_ex(seq, out3, &o3);
+		if (rc != OAKENGINE_OK) {
+			fprintf(stderr, "ex custom export failed (%d): %s\n", rc,
+					oakengine_export_last_error(err, sizeof(err)) > 0 ?
+						err :
+						"(no error)");
+		}
+		assert(rc == OAKENGINE_OK);
+		snprintf(cmd, sizeof(cmd),
+				 "ffprobe -v error -show_entries stream=codec_type,duration "
+				 "-of csv=p=0 \"%s\"",
+				 out3);
+		FILE *p3 = popen(cmd, "r");
+		assert(p3 != NULL);
+		char p3_out[512] = { 0 };
+		const size_t p3_len = fread(p3_out, 1, sizeof(p3_out) - 1, p3);
+		(void)p3_len;
+		assert(pclose(p3) == 0);
+		assert(strstr(p3_out, "video") != NULL);
+		assert(strstr(p3_out, "audio") != NULL);
+		// 20 frames at 30000/1001 ~= 0.667 s.
+		assert(strstr(p3_out, "0.6") != NULL);
+
+		// PNG sequence over 5 frames (image-sequence flag auto-fills the
+		// frame placeholder).
+		char out4[4096];
+		snprintf(out4, sizeof(out4), "%s/seqout.png", g_tmpdir);
+		oak_export_options_ex o4 = o3;
+		o4.range_in_ts = 0;
+		o4.range_out_ts = 5;
+		o4.format = 5; // ExportFormat::k_format_png
+		o4.video_codec = 5; // ExportCodec::k_codec_png
+		o4.audio_enabled = 0;
+		o4.is_image_sequence = 1;
+		rc = oakengine_export_render_ex(seq, out4, &o4);
+		if (rc != OAKENGINE_OK) {
+			fprintf(stderr, "ex png export failed (%d): %s\n", rc,
+					oakengine_export_last_error(err, sizeof(err)) > 0 ?
+						err :
+						"(no error)");
+		}
+		assert(rc == OAKENGINE_OK);
+		char png0[4096];
+		snprintf(png0, sizeof(png0), "%s/seqout_00000.png", g_tmpdir);
+		assert(access(png0, F_OK) == 0);
+		snprintf(cmd, sizeof(cmd), "file \"%s\"", png0);
+		assert_probe_matches(cmd, "PNG image data");
+
+		// Cancellation from another thread: either the export finishes
+		// first (idempotent) or reports E_CANCELLED; the exporter must stay
+		// usable afterwards.
+		oak_export_options_ex o5 = o3;
+		snprintf(out3, sizeof(out3), "%s/ex_cancel.mp4", g_tmpdir);
+		std::thread canceller([]() {
+			std::this_thread::sleep_for(std::chrono::milliseconds(100));
+			oakengine_export_cancel();
+		});
+		const int cancel_rc = oakengine_export_render_ex(seq, out3, &o5);
+		canceller.join();
+		assert(cancel_rc == OAKENGINE_OK ||
+			   cancel_rc == OAKENGINE_E_CANCELLED);
+		snprintf(out3, sizeof(out3), "%s/ex_after.mp4", g_tmpdir);
+		assert(oakengine_export_render_ex(seq, out3, &o5) == OAKENGINE_OK);
+	}
+
 	oakengine_project_free(project);
 	assert(oakengine_shutdown() == OAKENGINE_OK);