diff --git a/icons/icons.qrc b/icons/icons.qrc
index facafcbdd..3fc0faaf0 100644
--- a/icons/icons.qrc
+++ b/icons/icons.qrc
@@ -29,5 +29,6 @@
         <file>slip-disabled.png</file>
         <file>slide.png</file>
         <file>slide-disabled.png</file>
+        <file>throbber.png</file>
     </qresource>
 </RCC>
diff --git a/icons/throbber.png b/icons/throbber.png
new file mode 100644
index 000000000..208c0aecc
Binary files /dev/null and b/icons/throbber.png differ
diff --git a/io/previewgenerator.cpp b/io/previewgenerator.cpp
index 5b808e8aa..2804adced 100644
--- a/io/previewgenerator.cpp
+++ b/io/previewgenerator.cpp
@@ -1,7 +1,3 @@
-//
-// TODO: Fold this file into a multithreaded "file processor"
-//
-
 #include "previewgenerator.h"
 
 #include "media.h"
@@ -10,6 +6,9 @@
 #include <QPixmap>
 #include <QDebug>
 #include <QtMath>
+#include <QTreeWidgetItem>
+
+#define WAVEFORM_RESOLUTION 64
 
 extern "C" {
 #include <libavformat/avformat.h>
@@ -18,16 +17,46 @@ extern "C" {
 #include <libswresample/swresample.h>
 }
 
-PreviewGenerator::PreviewGenerator(QObject* parent) : QThread(parent) {
-    media = NULL;
-    fmt_ctx = NULL;
+PreviewGenerator::PreviewGenerator(QTreeWidgetItem* i, Media* m) : QThread(0), fmt_ctx(NULL), item(i), media(m) {
+    connect(this, SIGNAL(finished()), this, SLOT(deleteLater()));
 }
 
-#define WAVEFORM_RESOLUTION 64
+void PreviewGenerator::parse_media() {
+    // detect video/audio streams in file
+    for (int i=0;i<(int)fmt_ctx->nb_streams;i++) {
+        // Find the decoder for the video stream
+        if (avcodec_find_decoder(fmt_ctx->streams[i]->codecpar->codec_id) == NULL) {
+            qDebug() << "[ERROR] Unsupported codec in stream %d.\n";
+        } else {
+            MediaStream* ms = new MediaStream();
+            ms->preview_done = false;
+            ms->file_index = i;
+            if (fmt_ctx->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
+                bool infinite_length = (fmt_ctx->streams[i]->avg_frame_rate.den == 0);
+                ms->video_width = fmt_ctx->streams[i]->codecpar->width;
+                ms->video_height = fmt_ctx->streams[i]->codecpar->height;
+                ms->infinite_length = infinite_length;
+                media->video_tracks.append(ms);
+            } else if (fmt_ctx->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
+                ms->audio_channels = fmt_ctx->streams[i]->codecpar->channels;
+                media->audio_tracks.append(ms);
+            }
+        }
+    }
+    media->length = fmt_ctx->duration;
 
-void PreviewGenerator::run() {
-    Q_ASSERT(media != NULL);
+    media->ready = true;
 
+    if (media->video_tracks.size() == 0) {
+        emit set_icon(ICON_TYPE_AUDIO);
+    } else {
+        emit set_icon(ICON_TYPE_VIDEO);
+    }
+
+    item->setText(1, QString::number(media->length));
+}
+
+void PreviewGenerator::generate_waveform() {
     SwsContext* sws_ctx;
     SwrContext* swr_ctx;
     AVFrame* temp_frame = av_frame_alloc();
@@ -99,7 +128,7 @@ void PreviewGenerator::run() {
 
                     s->video_preview = QImage(data, dstW, dstH, linesize[0], QImage::Format_RGB888);
 
-                    //                                delete [] data;
+//                  delete [] data;
 
                     s->preview_done = true;
 
@@ -183,6 +212,41 @@ void PreviewGenerator::run() {
         }
     }
     delete [] codec_ctx;
+}
 
-    avformat_close_input(&fmt_ctx);
+void PreviewGenerator::run() {
+    Q_ASSERT(media != NULL);
+    Q_ASSERT(item != NULL);
+
+    QByteArray ba = media->url.toLatin1();
+    char* filename = new char[ba.size()+1];
+    strcpy(filename, ba.data());
+
+    bool error = false;
+    int errCode = avformat_open_input(&fmt_ctx, filename, NULL, NULL);
+    if(errCode != 0) {
+        char err[1024];
+        av_strerror(errCode, err, 1024);
+        item->setToolTip(0, "Could not open file - " + QString(err));
+        error = true;
+    } else {
+        errCode = avformat_find_stream_info(fmt_ctx, NULL);
+        if (errCode < 0) {
+            char err[1024];
+            av_strerror(errCode, err, 1024);
+            item->setToolTip(0, "Could not find stream information - " + QString(err));
+            error = true;
+        } else {
+            av_dump_format(fmt_ctx, 0, filename, 0);
+            parse_media();
+            generate_waveform();
+        }
+        avformat_close_input(&fmt_ctx);
+    }
+    if (error) {
+        emit set_icon(ICON_TYPE_ERROR);
+    } else {
+        item->setToolTip(0, QString());
+    }
+    delete [] filename;
 }
diff --git a/io/previewgenerator.h b/io/previewgenerator.h
index 35ffc3b5d..293c57614 100644
--- a/io/previewgenerator.h
+++ b/io/previewgenerator.h
@@ -3,15 +3,27 @@
 
 #include <QThread>
 
+#define ICON_TYPE_VIDEO 0
+#define ICON_TYPE_AUDIO 1
+#define ICON_TYPE_ERROR 2
+
 struct Media;
 struct MediaStream;
 struct AVFormatContext;
+class QTreeWidgetItem;
 
 class PreviewGenerator : public QThread
 {
+    Q_OBJECT
 public:
-    PreviewGenerator(QObject* parent = 0);
+    PreviewGenerator(QTreeWidgetItem*, Media*);
     void run();
+signals:
+    void set_icon(int);
+private:
+    void parse_media();
+    void generate_waveform();
+    QTreeWidgetItem* item;
     Media* media;
     AVFormatContext* fmt_ctx;
 };
diff --git a/mainwindow.cpp b/mainwindow.cpp
index 76bdbe5be..33f303884 100644
--- a/mainwindow.cpp
+++ b/mainwindow.cpp
@@ -27,6 +27,7 @@
 #include <QStandardPaths>
 #include <QTimer>
 #include <QCloseEvent>
+#include <QMovie>
 
 #define OLIVE_FILE_FILTER "Olive Project (*.ove)"
 
@@ -58,7 +59,7 @@ MainWindow::MainWindow(QWidget *parent) :
 	darkPalette.setColor(QPalette::WindowText, Qt::white);
 	darkPalette.setColor(QPalette::Base, QColor(25,25,25));
 	darkPalette.setColor(QPalette::AlternateBase, QColor(53,53,53));
-	darkPalette.setColor(QPalette::ToolTipBase, Qt::white);
+    darkPalette.setColor(QPalette::ToolTipBase, QColor(25,25,25));
 	darkPalette.setColor(QPalette::ToolTipText, Qt::white);
 	darkPalette.setColor(QPalette::Text, Qt::white);
 	darkPalette.setColor(QPalette::Button, QColor(53,53,53));
diff --git a/panels/project.cpp b/panels/project.cpp
index 6b0705edb..28fe01996 100644
--- a/panels/project.cpp
+++ b/panels/project.cpp
@@ -111,77 +111,22 @@ void Project::new_sequence(Sequence *s, bool open, QTreeWidgetItem* parent) {
 }
 
 QTreeWidgetItem* Project::import_file(QString file) {
-    QByteArray ba = file.toLatin1();
-    char* filename = new char[ba.size()+1];
-    strcpy(filename, ba.data());
-
     QTreeWidgetItem* item = new_item();
     Media* m = new Media();
     m->url = file;
     m->name = file.mid(file.lastIndexOf('/')+1);
     item->setText(0, m->name);
 
-    AVFormatContext* pFormatCtx = NULL;
-    int errCode = avformat_open_input(&pFormatCtx, filename, NULL, NULL);
-    if(errCode != 0) {
-        char err[1024];
-        av_strerror(errCode, err, 1024);
-        qDebug() << "[ERROR] Could not open" << filename << "-" << err;
-    } else {
-        errCode = avformat_find_stream_info(pFormatCtx, NULL);
-        if (errCode < 0) {
-            char err[1024];
-            av_strerror(errCode, err, 1024);
-            fprintf(stderr, "[ERROR] Could not find stream information. %s\n", err);
-        } else {
-            av_dump_format(pFormatCtx, 0, filename, 0);
-
-            // detect video/audio streams in file
-            for (int i=0;i<(int)pFormatCtx->nb_streams;i++) {
-                // Find the decoder for the video stream
-                if (avcodec_find_decoder(pFormatCtx->streams[i]->codecpar->codec_id) == NULL) {
-                    qDebug() << "[ERROR] Unsupported codec in stream %d.\n";
-                } else {
-                    MediaStream* ms = new MediaStream();
-                    ms->preview_done = false;
-                    ms->file_index = i;
-                    if (pFormatCtx->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
-                        bool infinite_length = (pFormatCtx->streams[i]->avg_frame_rate.den == 0);
-                        ms->video_width = pFormatCtx->streams[i]->codecpar->width;
-                        ms->video_height = pFormatCtx->streams[i]->codecpar->height;
-                        ms->infinite_length = infinite_length;
-                        m->video_tracks.append(ms);
-                    } else if (pFormatCtx->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
-                        ms->audio_channels = pFormatCtx->streams[i]->codecpar->channels;
-                        m->audio_tracks.append(ms);
-                    }
-                }
-            }
-            m->length = pFormatCtx->duration;
-
-            if (m->video_tracks.size() == 0) {
-                item->setIcon(0, QIcon(":/icons/audiosource.png"));
-            } else {
-                item->setIcon(0, QIcon(":/icons/videosource.png"));
-            }
-            item->setText(1, QString::number(m->length));
-
-            m->ready = true;
-
-            // generate waveform/thumbnail in another thread
-            PreviewGenerator* pg = new PreviewGenerator();
-            pg->fmt_ctx = pFormatCtx; // cleaned up in PG
-            pg->media = m;
-            connect(pg, SIGNAL(finished()), pg, SLOT(deleteLater()));
-            pg->start(QThread::LowPriority);
-        }
-    }
-
     set_media_of_tree(item, m);
 
-    project_changed = true;
+    // set up throbber animation
+    MediaThrobber* throbber = new MediaThrobber(item);
+
+    // generate waveform/thumbnail in another thread
+    PreviewGenerator* pg = new PreviewGenerator(item, m);
+    connect(pg, SIGNAL(set_icon(int)), throbber, SLOT(stop(int)));
+    pg->start(QThread::LowPriority);
 
-    delete [] filename;
     return item;
 }
 
@@ -377,6 +322,7 @@ void Project::process_file_list(QStringList& files) {
 
         ta->add_media(import_file(file));
         imported = true;
+        project_changed = true;
     }
     if (imported) {
         undo_stack.push(ta);
@@ -935,3 +881,33 @@ void Project::add_recent_project(QString url) {
     }
     save_recent_projects();
 }
+
+#define THROBBER_LIMIT 20
+#define THROBBER_SIZE 50
+
+MediaThrobber::MediaThrobber(QTreeWidgetItem* i) : pixmap(":/icons/throbber.png"), item(i), animation(0) {
+    // set up throbber
+    animation_update();
+    animator.setInterval(20);
+    connect(&animator, SIGNAL(timeout()), this, SLOT(animation_update()));
+    animator.start();
+}
+
+void MediaThrobber::animation_update() {
+    if (animation == THROBBER_LIMIT) {
+        animation = 0;
+    }
+    item->setIcon(0, QIcon(pixmap.copy(THROBBER_SIZE*animation, 0, THROBBER_SIZE, THROBBER_SIZE)));
+    animation++;
+}
+
+void MediaThrobber::stop(int icon_type) {
+    animator.stop();
+    switch (icon_type) {
+    case ICON_TYPE_VIDEO: item->setIcon(0, QIcon(":/icons/videosource.png")); break;
+    case ICON_TYPE_AUDIO: item->setIcon(0, QIcon(":/icons/audiosource.png")); break;
+    case ICON_TYPE_ERROR: item->setIcon(0, QIcon::fromTheme("dialog-error")); break;
+    }
+    panel_project->source_table->viewport()->update();
+    deleteLater();
+}
diff --git a/panels/project.h b/panels/project.h
index 773f4d23b..07525755c 100644
--- a/panels/project.h
+++ b/panels/project.h
@@ -3,6 +3,7 @@
 
 #include <QDockWidget>
 #include <QVector>
+#include <QTimer>
 
 struct Media;
 struct Sequence;
@@ -84,4 +85,19 @@ private slots:
     void clear_recent_projects();
 };
 
+class MediaThrobber : public QObject {
+    Q_OBJECT
+public:
+    MediaThrobber(QTreeWidgetItem*);
+public slots:
+    void stop(int);
+private slots:
+    void animation_update();
+private:
+    QPixmap pixmap;
+    int animation;
+    QTreeWidgetItem* item;
+    QTimer animator;
+};
+
 #endif // PROJECT_H
diff --git a/project/effect.cpp b/project/effect.cpp
index bec57d341..dd8575f8e 100644
--- a/project/effect.cpp
+++ b/project/effect.cpp
@@ -35,11 +35,5 @@ bool Effect::is_enabled() {
 Effect* Effect::copy(Clip*) {return NULL;}
 void Effect::load(QXmlStreamReader*) {}
 void Effect::save(QXmlStreamWriter*) {}
-/*void Effect::import_values(float* val, int count) {
-    qDebug() << "[ERROR] import_values MUST be overridden";
-}
-void Effect::export_values(float* val, int* count) {
-    qDebug() << "[ERROR] export_values MUST be overridden";
-}*/
 void Effect::process_gl(int*, int*) {}
 void Effect::process_audio(uint8_t*, int) {}