Allow waveform sync with partially cached audio and add regression tests

app/widget/timelinewidget/timelinewidgetwaveformsync.cpp

@@ -0,0 +1,126 @@
+/***
+
+  Olive - Non-Linear Video Editor
+  Copyright (C) 2022 Olive Team
+  Modifications Copyright (C) 2025 mikesolar
+
+  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, either version 3 of the License, or
+  (at your option) any later version.
+
+  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 <http://www.gnu.org/licenses/>.
+
+***/
+
+#include "timelinewidgetwaveformsync.h"
+
+#include <cmath>
+
+#include "node/block/clip/clip.h"
+#include "render/audiowaveformcache.h"
+
+namespace olive
+{
+
+namespace TimelineWaveformSync
+{
+
+bool GetWaveformSyncClip(Block *block, WaveformSyncClip *out)
+{
+	ClipBlock *clip = dynamic_cast<ClipBlock *>(block);
+	if (!clip || !clip->waveform()) {
+		return false;
+	}
+
+	const TimeRange media_range = clip->media_range();
+	if (media_range.length().isNull()) {
+		return false;
+	}
+
+	const AudioWaveformCache *waveform = clip->waveform();
+	if (waveform->GetParameters().sample_rate() <= 0) {
+		return false;
+	}
+
+	// Allow waveform sync as long as at least some portion of the clip's
+	// media range has been validated. Requiring the entire range to be
+	// validated makes the menu item stay disabled for long clips and gives
+	// the appearance that "nothing happens" when the user tries to sync.
+	const TimeRangeList validated_ranges =
+		waveform->GetValidatedRanges().Intersects(media_range);
+	if (validated_ranges.isEmpty()) {
+		return false;
+	}
+
+	out->clip = clip;
+	out->waveform = waveform;
+	out->media_range = media_range;
+	out->sample_rate = waveform->GetParameters().sample_rate();
+	return true;
+}
+
+QVector<WaveformSyncClip> GetSelectedWaveformSyncClips(
+	const QVector<Block *> &blocks)
+{
+	QVector<WaveformSyncClip> clips;
+	for (Block *block : blocks) {
+		WaveformSyncClip sync_clip;
+		if (GetWaveformSyncClip(block, &sync_clip)) {
+			clips.append(sync_clip);
+		}
+	}
+	return clips;
+}
+
+QVector<double> ExtractWaveformCacheEnvelope(const WaveformSyncClip &clip,
+											 int sample_rate,
+											 size_t window_samples)
+{
+	QVector<double> envelope;
+	if (sample_rate <= 0 || !window_samples) {
+		return envelope;
+	}
+
+	const rational window_time(static_cast<int>(window_samples), sample_rate);
+
+	// Only trust regions that have actually been validated. Unvalidated cache
+	// returns zero samples, which both drags the correlation score down and
+	// can produce false peaks if one clip happens to have more cached data
+	// than another. Using zero placeholders keeps every envelope aligned to
+	// the same absolute timeline.
+	const TimeRangeList validated_ranges =
+		clip.waveform->GetValidatedRanges().Intersects(clip.media_range);
+
+	for (rational t = clip.media_range.in(); t < clip.media_range.out();
+		 t += window_time) {
+		const rational length = qMin(window_time, clip.media_range.out() - t);
+		const TimeRange window(t, t + length);
+
+		double peak = 0.0;
+		if (validated_ranges.contains(window)) {
+			const AudioVisualWaveform::Sample summary =
+				clip.waveform->GetSummaryFromTime(t, length);
+
+			for (const AudioVisualWaveform::SamplePerChannel &channel : summary) {
+				const double channel_peak =
+					std::max(std::abs(static_cast<double>(channel.min)),
+							 std::abs(static_cast<double>(channel.max)));
+				peak = std::max(peak, channel_peak);
+			}
+		}
+
+		envelope.append(peak);
+	}
+	return envelope;
+}
+
+}  // namespace TimelineWaveformSync
+
+}  // namespace olive