diff --git a/client/port.cpp b/client/port.cpp
index 90992ab..3130432 100644
--- a/client/port.cpp
+++ b/client/port.cpp
@@ -22,10 +22,14 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>
 #include "abstractfileformat.h"
 
 #include <QApplication>
+#include <QMainWindow>
+#include <QProgressDialog>
 #include <QVariant>
 #include <google/protobuf/descriptor.h>
 #include <vector>
 
+extern QMainWindow *mainWindow;
+
 uint Port::mAllocStreamId = 0;
 
 uint Port::newStreamId()
@@ -225,52 +229,137 @@ void Port::updateStats(OstProto::PortStats *portStats)
 
 bool Port::openStreams(QString fileName, bool append, QString &error)
 {
+    bool ret = false; 
+    QProgressDialog progress("Opening Streams", "Cancel", 0, 0, mainWindow);
     OstProto::StreamConfigList streams;
     AbstractFileFormat *fmt = AbstractFileFormat::fileFormatFromFile(fileName);
 
     if (fmt == NULL)
         goto _fail;
 
-    if (!fmt->openStreams(fileName, streams, error))
+    progress.setAutoReset(false);
+    progress.setAutoClose(false);
+    progress.setMinimumDuration(0);
+    progress.show();
+
+    mainWindow->setDisabled(true);
+    progress.setEnabled(true); // to override the mainWindow disable
+
+    connect(fmt, SIGNAL(status(QString)),&progress,SLOT(setLabelText(QString)));
+    connect(fmt, SIGNAL(target(int)), &progress, SLOT(setMaximum(int)));
+    connect(fmt, SIGNAL(progress(int)), &progress, SLOT(setValue(int)));
+    connect(&progress, SIGNAL(canceled()), fmt, SLOT(cancel()));
+
+    fmt->openStreamsOffline(fileName, streams, error);
+    qDebug("after open offline");
+
+    while (!fmt->isFinished())
+        qApp->processEvents();
+    qDebug("wait over for offline operation");
+
+    if (!fmt->result())
         goto _fail;
+    
+    // process any remaining events posted from the thread
+    for (int i = 0; i < 10; i++)
+        qApp->processEvents();
 
     if (!append)
     {
-        while (numStreams())
+        int n = numStreams();
+
+        progress.setLabelText("Deleting existing streams...");
+        progress.setRange(0, n);
+        for (int i = 0; i < n; i++)
+        {
+            if (progress.wasCanceled())
+                goto _user_cancel;
             deleteStreamAt(0);
+            progress.setValue(i);
+            if (i % 32 == 0)
+                qApp->processEvents();
+        }
     }
 
+    progress.setLabelText("Constructing new streams...");
+    progress.setRange(0, streams.stream_size());
     for (int i = 0; i < streams.stream_size(); i++)
     {
+        if (progress.wasCanceled())
+            goto _user_cancel;
         newStreamAt(mStreams.size(), &streams.stream(i));
+        progress.setValue(i);
+        if (i % 32 == 0)
+            qApp->processEvents();
     }
 
+_user_cancel:
     emit streamListChanged(mPortGroupId, mPortId);
-
-    return true;
+    ret = true;
 
 _fail:
-    return false;
+    progress.close();
+    mainWindow->setEnabled(true);
+    return ret;
 }
 
 bool Port::saveStreams(QString fileName, QString fileType, QString &error)
 {
+    bool ret = false;
+    QProgressDialog progress("Saving Streams", "Cancel", 0, 0, mainWindow);
     AbstractFileFormat *fmt = AbstractFileFormat::fileFormatFromType(fileType);
     OstProto::StreamConfigList streams;
 
     if (fmt == NULL)
         goto _fail;
 
+    progress.setAutoReset(false);
+    progress.setAutoClose(false);
+    progress.setMinimumDuration(0);
+    progress.show();
+
+    mainWindow->setDisabled(true);
+    progress.setEnabled(true); // to override the mainWindow disable
+
+    connect(fmt, SIGNAL(status(QString)),&progress,SLOT(setLabelText(QString)));
+    connect(fmt, SIGNAL(target(int)), &progress, SLOT(setMaximum(int)));
+    connect(fmt, SIGNAL(progress(int)), &progress, SLOT(setValue(int)));
+    connect(&progress, SIGNAL(canceled()), fmt, SLOT(cancel()));
+
+    progress.setLabelText("Preparing Streams...");
+    progress.setRange(0, mStreams.size());
     streams.mutable_port_id()->set_id(0);
     for (int i = 0; i < mStreams.size(); i++)
     {
         OstProto::Stream *s = streams.add_stream();
         mStreams[i]->protoDataCopyInto(*s);
+
+        if (progress.wasCanceled())
+            goto _user_cancel;
+        progress.setValue(i);
+        if (i % 32 == 0)
+            qApp->processEvents();
     }
 
-    return fmt->saveStreams(streams, fileName, error);
+    fmt->saveStreamsOffline(streams, fileName, error);
+    qDebug("after save offline");
+
+    while (!fmt->isFinished())
+        qApp->processEvents();
+    qDebug("wait over for offline operation");
+
+    ret = fmt->result();
+    goto _exit;
+
+_user_cancel:
+   goto _exit; 
 
 _fail:
     error = QString("Unsupported File Type - %1").arg(fileType);
-    return false;
+    goto _exit;
+
+_exit:
+    progress.close();
+    mainWindow->setEnabled(true);
+    return ret;
 }
diff --git a/client/portswindow.cpp b/client/portswindow.cpp
index 86bcf71..a2cf238 100644
--- a/client/portswindow.cpp
+++ b/client/portswindow.cpp
@@ -458,14 +458,15 @@ void PortsWindow::on_actionOpen_Streams_triggered()
 
     Q_ASSERT(plm->isPort(current));
 
-    fileName = QFileDialog::getOpenFileName(this, tr("Open Streams"));
+    fileName = QFileDialog::getOpenFileName(this, tr("Open Streams"), "D:/srivatsp/projects/ostinato/testfiles/pcaps");
     if (fileName.isEmpty())
         goto _exit;
 
     if (tvStreamList->model()->rowCount())
     {
         QMessageBox msgBox(QMessageBox::Question, qApp->applicationName(),
-                tr("Append to existing streams? Or overwrite?"));
+                tr("Append to existing streams? Or overwrite?"),
+                QMessageBox::NoButton, this);
         QPushButton *appendBtn = msgBox.addButton(tr("Append"), 
                 QMessageBox::ActionRole);
         QPushButton *overwriteBtn = msgBox.addButton(tr("Overwrite"), 
diff --git a/common/abstractfileformat.cpp b/common/abstractfileformat.cpp
index cb3fa43..f748447 100644
--- a/common/abstractfileformat.cpp
+++ b/common/abstractfileformat.cpp
@@ -27,6 +27,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>
 
 AbstractFileFormat::AbstractFileFormat()
 {
+    stop_ = false;
 }
 
 AbstractFileFormat::~AbstractFileFormat()
@@ -40,10 +41,40 @@ QStringList AbstractFileFormat::supportedFileTypes()
         << "PCAP (*)"
         << "PDML (*.pdml)";
 }
+
+void AbstractFileFormat::openStreamsOffline(const QString fileName, 
+        OstProto::StreamConfigList &streams, QString &error)
+{
+    fileName_ = fileName;
+    openStreams_ = &streams;
+    error_ = &error;
+    op_ = kOpen;
+    stop_ = false;
+
+    start();
+}
+
+void AbstractFileFormat::saveStreamsOffline(
+        const OstProto::StreamConfigList streams, 
+        const QString fileName, QString &error)
+{
+    saveStreams_ = streams;
+    fileName_ = fileName;
+    error_ = &error;
+    op_ = kSave;
+    stop_ = false;
+
+    start();
+}
+
+bool AbstractFileFormat::result()
+{
+    return result_;
+}
+
 AbstractFileFormat* AbstractFileFormat::fileFormatFromFile(
         const QString fileName)
 {
-
     if (fileFormat.isMyFileFormat(fileName))
         return &fileFormat;
 
@@ -71,3 +102,16 @@ AbstractFileFormat* AbstractFileFormat::fileFormatFromType(
 
     return NULL;
 }
+
+void AbstractFileFormat::cancel()
+{
+    stop_ = true;
+}
+
+void AbstractFileFormat::run()
+{
+    if (op_ == kOpen)
+        result_ = openStreams(fileName_, *openStreams_, *error_);
+    else if (op_ == kSave)
+        result_ = saveStreams(saveStreams_, fileName_, *error_);
+}
diff --git a/common/abstractfileformat.h b/common/abstractfileformat.h
index 7a648ee..031e4e1 100644
--- a/common/abstractfileformat.h
+++ b/common/abstractfileformat.h
@@ -22,12 +22,12 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>
 
 #include "protocol.pb.h"
 
-#include <QObject>
+#include <QThread>
 #include <QString>
 
-class AbstractFileFormat : public QObject
+class AbstractFileFormat : public QThread
 {
-    Q_OBJECT 
+    Q_OBJECT
 public:
     AbstractFileFormat();
     virtual ~AbstractFileFormat();
@@ -37,6 +37,13 @@ public:
     virtual bool saveStreams(const OstProto::StreamConfigList streams, 
             const QString fileName, QString &error) = 0;
 
+    void openStreamsOffline(const QString fileName, 
+            OstProto::StreamConfigList &streams, QString &error);
+    void saveStreamsOffline(const OstProto::StreamConfigList streams, 
+            const QString fileName, QString &error);
+
+    bool result();
+
     static AbstractFileFormat* fileFormatFromFile(const QString fileName);
     static AbstractFileFormat* fileFormatFromType(const QString fileType);
 
@@ -46,6 +53,33 @@ public:
     bool isMyFileFormat(const QString fileName) = 0;
     bool isMyFileType(const QString fileType) = 0;
 #endif
+
+signals:
+    void status(QString text);
+    void target(int value);
+    void progress(int value);
+
+public slots:
+    void cancel();
+
+protected:
+    void run();
+
+    bool stop_;
+
+private:
+    enum kOp
+    {
+        kOpen,
+        kSave 
+    };
+    QString fileName_;
+    OstProto::StreamConfigList *openStreams_;
+    OstProto::StreamConfigList saveStreams_;
+    QString *error_;
+    kOp op_;
+    bool result_;
+
 };
 
 #endif
diff --git a/common/fileformat.cpp b/common/fileformat.cpp
index 7ddc65b..aada8b1 100644
--- a/common/fileformat.cpp
+++ b/common/fileformat.cpp
@@ -322,6 +322,8 @@ bool FileFormat::saveStreams(const OstProto::StreamConfigList streams,
         goto _zero_cksum_serialize_fail;
     }
 
+    emit status("Calculating checksum...");
+
     // Calculate and write checksum
     calcCksum = checksumCrc32C((quint8*)buf.constData(), buf.size());
     cksum.set_value(calcCksum);
@@ -335,6 +337,7 @@ bool FileFormat::saveStreams(const OstProto::StreamConfigList streams,
     qDebug("Writing %d bytes", buf.size());
     //qDebug("%s", QString(buf.toHex()).toAscii().constData());
 
+    emit status("Writing to disk...");
     if (!file.open(QIODevice::WriteOnly | QIODevice::Truncate))
         goto _open_fail;
 
diff --git a/common/pcapfileformat.cpp b/common/pcapfileformat.cpp
index a893565..04ace99 100644
--- a/common/pcapfileformat.cpp
+++ b/common/pcapfileformat.cpp
@@ -64,7 +64,7 @@ PcapFileFormat::~PcapFileFormat()
 bool PcapFileFormat::openStreams(const QString fileName, 
             OstProto::StreamConfigList &streams, QString &error)
 {
-    bool viaPdml = true; // TODO: shd be a param to function
+    bool viaPdml = false; // TODO: shd be a param to function
 
     bool isOk = false;
     QFile file(fileName);
@@ -77,6 +77,8 @@ bool PcapFileFormat::openStreams(const QString fileName,
     OstProto::Stream *prevStream = NULL;
     uint lastUsec = 0;
     int pktCount;
+    qint64 byteCount = 0;
+    qint64 byteTotal;
     QByteArray pktBuf;
 
     if (!file.open(QIODevice::ReadOnly))
@@ -90,6 +92,9 @@ bool PcapFileFormat::openStreams(const QString fileName,
     {
         QProcess gzip;
 
+        emit status("Decompressing...");
+        emit target(0);
+
         if (!file2.open())
         {
             error.append("Unable to open temporary file to uncompress .gz\n");
@@ -126,6 +131,11 @@ bool PcapFileFormat::openStreams(const QString fileName,
         fd_.setDevice(&file);
     }
 
+    byteTotal = fd_.device()->size() - sizeof(fileHdr);
+
+    emit status("Reading File Header...");
+    emit target(0);
+
     fd_ >> magic;
 
     qDebug("magic = %08x", magic);
@@ -173,6 +183,8 @@ bool PcapFileFormat::openStreams(const QString fileName,
         }
 
         qDebug("generating PDML %s", pdmlFile.fileName().toAscii().constData());
+        emit status("Generating PDML...");
+        emit target(0);
 
         tshark.setStandardOutputFile(pdmlFile.fileName());
         // FIXME: hardcoded prog name
@@ -193,12 +205,18 @@ bool PcapFileFormat::openStreams(const QString fileName,
             goto _non_pdml;
         }
 
-        isOk = reader.read(&pdmlFile, this); // TODO: pass error string?
+        connect(&reader, SIGNAL(progress(int)), this, SIGNAL(progress(int)));
+
+        emit status("Reading PDML packets...");
+        emit target(100); // in percentage
+        isOk = reader.read(&pdmlFile, this, &stop_); // TODO: pass error string?
         goto _exit;
        
     }
 
 _non_pdml:
+    emit status("Reading Packets...");
+    emit target(100);  // in percentage
     pktCount = 1;
     while (!fd_.atEnd())
     {
@@ -235,11 +253,20 @@ _non_pdml:
         lastUsec = usec;
         prevStream = stream;
         pktCount++;
+        qDebug("pktCount = %d", pktCount);
+        byteCount += pktHdr.inclLen + sizeof(pktHdr);
+        emit progress(int(byteCount*100/byteTotal)); // in percentage
+        if (stop_)
+            goto _user_cancel;
     }
 
     isOk = true;
     goto _exit;
 
+_user_cancel:
+    isOk = true;
+    goto _exit;
+
 #if 1
 _err_unsupported_encap:
     error = QString(tr("%1 has non-ethernet encapsulation (%2) which is "
@@ -344,6 +371,9 @@ bool PcapFileFormat::saveStreams(const OstProto::StreamConfigList streams,
 
     pktBuf.resize(kMaxSnapLen);
 
+    emit status("Writing Packets...");
+    emit target(streams.stream_size());
+
     pktHdr.tsSec = 0;
     pktHdr.tsUsec = 0;
     for (int i = 0; i < streams.stream_size(); i++)
@@ -377,6 +407,8 @@ bool PcapFileFormat::saveStreams(const OstProto::StreamConfigList streams,
             pktHdr.tsSec++;
             pktHdr.tsUsec -= 1000000;
         }
+
+        emit progress(i);
     }
 
     file.close();
diff --git a/common/pdml_p.cpp b/common/pdml_p.cpp
index ae1c7ce..3dac8e0 100644
--- a/common/pdml_p.cpp
+++ b/common/pdml_p.cpp
@@ -115,6 +115,8 @@ PdmlReader::PdmlReader(OstProto::StreamConfigList *streams)
     currentStream_ = NULL;
     prevStream_ = NULL;
 
+    stop_ = NULL;
+
     factory_.insert("hexdump", PdmlUnknownProtocol::createInstance);
     factory_.insert("geninfo", PdmlGenInfoProtocol::createInstance);
     factory_.insert("frame", PdmlFrameProtocol::createInstance);
@@ -128,12 +130,13 @@ PdmlReader::~PdmlReader()
 {
 }
 
-bool PdmlReader::read(QIODevice *device, PcapFileFormat *pcap)
+bool PdmlReader::read(QIODevice *device, PcapFileFormat *pcap, bool *stop)
 {
     setDevice(device);
     pcap_ = pcap;
     packetCount_ = 0;
 
+    stop_ = stop;
     while (!atEnd())
     {
         readNext();
@@ -146,7 +149,7 @@ bool PdmlReader::read(QIODevice *device, PcapFileFormat *pcap)
         }
     }
 
-    if (error())
+    if (error() && (errorString() != "USER-CANCEL"))
     {
         qDebug("Line %lld", lineNumber());
         qDebug("Col %lld", columnNumber());
@@ -325,8 +328,11 @@ void PdmlReader::readPacket()
     } 
 
     packetCount_++;
+    emit progress(int(characterOffset()*100/device()->size()));
     if (prevStream_)
         prevStream_->mutable_control()->CopyFrom(currentStream_->control());
+    if (stop_ && *stop_)
+        raiseError("USER-CANCEL");
 }
 
 void PdmlReader::readProto()
diff --git a/common/pdml_p.h b/common/pdml_p.h
index 42ea327..af7c4f6 100644
--- a/common/pdml_p.h
+++ b/common/pdml_p.h
@@ -62,14 +62,18 @@ protected:
 
 class PdmlUnknownProtocol;
 class PcapFileFormat;
-class PdmlReader : public QXmlStreamReader
+class PdmlReader : public QObject, public QXmlStreamReader
 {
+    Q_OBJECT
     friend class PdmlUnknownProtocol;
 public:
     PdmlReader(OstProto::StreamConfigList *streams);
     ~PdmlReader();
 
-    bool read(QIODevice *device, PcapFileFormat *pcap = NULL);
+    bool read(QIODevice *device, PcapFileFormat *pcap = NULL, 
+            bool *stop = NULL);
+signals:
+    void progress(int value);
 
 private:
     PdmlDefaultProtocol* allocPdmlProtocol(QString protoName);
@@ -103,6 +107,7 @@ private:
     OstProto::Stream *currentStream_;
 
     QByteArray pktBuf_;
+    bool *stop_;
 };
 
 class PdmlUnknownProtocol : public PdmlDefaultProtocol
diff --git a/common/pdmlfileformat.cpp b/common/pdmlfileformat.cpp
index 0c51652..1e2c4c8 100644
--- a/common/pdmlfileformat.cpp
+++ b/common/pdmlfileformat.cpp
@@ -30,39 +30,6 @@ PdmlFileFormat::~PdmlFileFormat()
 {
 }
 
-#if 0
-bool PdmlFileFormat::openStreams(const QString fileName, 
-            OstProto::StreamConfigList &streams, QString &error)
-{
-    bool isOk;
-    QFile file(fileName);
-    PdmlParser *pdml;
-    QXmlSimpleReader *xmlReader;
-    QXmlInputSource *xmlSource;
-
-    if (!file.open(QIODevice::ReadOnly))
-        goto _open_fail;
-
-    pdml = new PdmlParser(&streams);
-    xmlSource = new QXmlInputSource(&file);
-    xmlReader = new QXmlSimpleReader;
-    xmlReader->setContentHandler(pdml);
-    xmlReader->setErrorHandler(pdml);
-    isOk = xmlReader->parse(xmlSource, false); // non-incremental parse
-
-    goto _exit;
-
-_open_fail:
-    isOk = false;
-
-_exit:
-    delete xmlReader;
-    delete xmlSource;
-    delete pdml;
-
-    return isOk;
-}
-#else
 bool PdmlFileFormat::openStreams(const QString fileName, 
             OstProto::StreamConfigList &streams, QString &error)
 {
@@ -73,6 +40,10 @@ bool PdmlFileFormat::openStreams(const QString fileName,
     if (!file.open(QIODevice::ReadOnly))
         goto _open_fail;
 
+    connect(reader, SIGNAL(progress(int)), this, SIGNAL(progress(int)));
+    emit status("Reading PDML packets...");
+    emit target(100); // in percentage
+
     // TODO: fill in error string
 
     isOk = reader->read(&file); 
@@ -87,7 +58,6 @@ _exit:
 
     return isOk;
 }
-#endif
 
 bool PdmlFileFormat::saveStreams(const OstProto::StreamConfigList streams, 
         const QString fileName, QString &error)