added speed changes while maintaining audio pitch

dialogs/speeddialog.cpp

@@ -43,9 +43,12 @@ SpeedDialog::SpeedDialog(QWidget *parent) : QDialog(parent) {
 	main_layout->addLayout(grid);
 
 	reverse = new QCheckBox("Reverse");
+	maintain_pitch = new QCheckBox("Maintain Audio Pitch");
+	ripple = new QCheckBox("Ripple Changes");
+
 	main_layout->addWidget(reverse);
-	main_layout->addWidget(new QCheckBox("Maintain Audio Pitch"));
-	main_layout->addWidget(new QCheckBox("Ripple"));
+	main_layout->addWidget(maintain_pitch);
+	main_layout->addWidget(ripple);
 
 	QDialogButtonBox* buttonBox = new QDialogButtonBox(QDialogButtonBox::Ok | QDialogButtonBox::Cancel);
 	buttonBox->setCenterButtons(true);
@@ -179,6 +182,8 @@ void SpeedDialog::accept() {
 		c->timeline_out = proposed_out;
 
 		c->recalculateMaxLength();
+
+		c->maintain_audio_pitch = maintain_pitch->isChecked();
 	}
 	panel_timeline->redraw_all_clips(true);
 	QDialog::accept();

dialogs/speeddialog.h

@@ -26,6 +26,8 @@ private:
 	LabelSlider* frame_rate;
 
 	QCheckBox* reverse;
+	QCheckBox* maintain_pitch;
+	QCheckBox* ripple;
 
 	double default_frame_rate;
 	double current_frame_rate;

playback/cacher.cpp

@@ -490,13 +490,28 @@ void open_clip_worker(Clip* clip) {
 				qDebug() << "[ERROR] Could not set output sample format";
 			}
 
-			int sample_rates[] = { qRound(sequence->audio_frequency / clip->speed), 0 };
+			int target_sample_rate = sequence->audio_frequency;
+
+			if (qFuzzyCompare(clip->speed, 1.0)) {
+				avfilter_link(clip->buffersrc_ctx, 0, clip->buffersink_ctx, 0);
+			} else if (clip->maintain_audio_pitch) {
+				char speed_param[10];
+				snprintf(speed_param, sizeof(speed_param), "%f", clip->speed);
+
+				AVFilterContext* tempo_filter;
+				avfilter_graph_create_filter(&tempo_filter, avfilter_get_by_name("atempo"), "atempo", speed_param, NULL, clip->filter_graph);
+				avfilter_link(clip->buffersrc_ctx, 0, tempo_filter, 0);
+				avfilter_link(tempo_filter, 0, clip->buffersink_ctx, 0);
+			} else {
+				target_sample_rate = qRound(sequence->audio_frequency / clip->speed);
+				avfilter_link(clip->buffersrc_ctx, 0, clip->buffersink_ctx, 0);
+			}
+
+			int sample_rates[] = { target_sample_rate, 0 };
 			if (av_opt_set_int_list(clip->buffersink_ctx, "sample_rates", sample_rates, 0, AV_OPT_SEARCH_CHILDREN) < 0) {
 				qDebug() << "[ERROR] Could not set output sample rates";
 			}
 
-			avfilter_link(clip->buffersrc_ctx, 0, clip->buffersink_ctx, 0);
-
 			avfilter_graph_config(clip->filter_graph, NULL);
 
 			clip->audio_reset = true;

project/clip.cpp

@@ -33,7 +33,8 @@ Clip::Clip(Sequence* s) :
 	filter_graph(NULL),
 	texture(NULL),
 	fbo(NULL),
-    autoscale(config.autoscale_by_default)
+	autoscale(config.autoscale_by_default),
+	maintain_audio_pitch(false)
 {
     reset();
 }

project/clip.h

@@ -116,8 +116,8 @@ struct Clip
     long texture_frame;
 	bool autoscale;
 
-    // audio playback variables
-//	SwrContext* swr_ctx;
+	// audio playback variables
+	bool maintain_audio_pitch;
     int frame_sample_index;
     int audio_buffer_write;
     bool audio_reset;