RTP Player: UI improvements

Changes:
- all waveforms has common scale therefore louder/quiter signal is visible
- when stream/streams are deleted from view, Y axis is rescaled and
  waveforms are rearranged to reuse empty space

ui/qt/rtp_audio_stream.cpp

@@ -52,6 +52,7 @@ RtpAudioStream::RtpAudioStream(QObject *parent, rtpstream_info_t *rtpstream, boo
     audio_resampler_(0),
     audio_output_(0),
     max_sample_val_(1),
+    max_sample_val_used_(1),
     color_(0),
     jitter_buffer_size_(50),
     timing_mode_(RtpAudioStream::JitterBuffer),
@@ -457,6 +458,7 @@ void RtpAudioStream::decodeVisual()
         }
     }
 
+    max_sample_val_used_ = max_sample_val_;
     g_free(resample_buff);
     g_free(read_buff);
 }
@@ -480,18 +482,15 @@ const QVector<double> RtpAudioStream::visualTimestamps(bool relative)
     return adj_timestamps;
 }
 
-// Scale the height of the waveform (max_sample_val_) and adjust its Y
-// offset so that they overlap slightly (stack_offset_).
-
-// XXX This means that waveforms can be misleading with respect to relative
-// amplitude. We might want to add a "global" max_sample_val_.
+// Scale the height of the waveform to global scale (max_sample_val_used_)
+// and adjust its Y offset so that they overlap slightly (stack_offset_).
 static const double stack_offset_ = G_MAXINT16 / 3;
 const QVector<double> RtpAudioStream::visualSamples(int y_offset)
 {
     QVector<double> adj_samples;
     double scaled_offset = y_offset * stack_offset_;
     for (int i = 0; i < visual_samples_.size(); i++) {
-        adj_samples.append(((double)visual_samples_[i] * G_MAXINT16 / max_sample_val_) + scaled_offset);
+        adj_samples.append(((double)visual_samples_[i] * G_MAXINT16 / max_sample_val_used_) + scaled_offset);
     }
     return adj_samples;
 }

ui/qt/rtp_audio_stream.h

@@ -144,6 +144,8 @@ public:
     void pausePlaying();
     void stopPlaying();
     void setStereoRequired(bool stereo_required) { stereo_required_ = stereo_required; }
+    qint16 getMaxSampleValue() { return max_sample_val_; }
+    void setMaxSampleValue(gint16 max_sample_val) { max_sample_val_used_ = max_sample_val; }
 
 signals:
     void processedSecs(double secs);
@@ -181,6 +183,7 @@ private:
     QVector<double> wrong_timestamp_timestamps_;
     QVector<double> silence_timestamps_;
     qint16 max_sample_val_;
+    qint16 max_sample_val_used_;
     QRgb color_;
 
     int jitter_buffer_size_;

ui/qt/rtp_player_dialog.cpp

@@ -411,6 +411,7 @@ void RtpPlayerDialog::createPlot(bool rescale_axes)
     bool legend_inserted_silences = false;
     bool relative_timestamps = !ui->todCheckBox->isChecked();
     int row_count = ui->streamTreeWidget->topLevelItemCount();
+    gint16 total_max_sample_value = 1;
 
     ui->audioPlot->clearGraphs();
 
@@ -420,6 +421,17 @@ void RtpPlayerDialog::createPlot(bool rescale_axes)
         ui->audioPlot->xAxis->setTicker(datetime_ticker_);
     }
 
+    // Calculate common Y scale for graphs
+    for (int row = 0; row < row_count; row++) {
+        QTreeWidgetItem *ti = ui->streamTreeWidget->topLevelItem(row);
+        RtpAudioStream *audio_stream = ti->data(stream_data_col_, Qt::UserRole).value<RtpAudioStream*>();
+        gint16 max_sample_value = audio_stream->getMaxSampleValue();
+
+        if (max_sample_value > total_max_sample_value) {
+            total_max_sample_value = max_sample_value;
+        }
+    }
+
     // Clear existing graphs
     for (int row = 0; row < row_count; row++) {
         QTreeWidgetItem *ti = ui->streamTreeWidget->topLevelItem(row);
@@ -433,6 +445,9 @@ void RtpPlayerDialog::createPlot(bool rescale_axes)
         ti->setData(graph_timestamp_data_col_, Qt::UserRole, QVariant());
         ti->setData(graph_silence_data_col_, Qt::UserRole, QVariant());
 
+        // Set common scale
+        audio_stream->setMaxSampleValue(total_max_sample_value);
+
         // Waveform
         RtpAudioGraph *audio_graph = new RtpAudioGraph(ui->audioPlot, audio_stream->color());
         audio_graph->setMuted(audio_routing.isMuted());
@@ -933,6 +948,22 @@ void RtpPlayerDialog::resetXAxis()
     ap->replot();
 }
 
+void RtpPlayerDialog::updateGraphs()
+{
+    QCustomPlot *ap = ui->audioPlot;
+
+    // Create new plots, just existing ones
+    createPlot(false);
+
+    // Rescale Y axis
+    double pixel_pad = 10.0; // per side
+    double axis_pixels = ap->yAxis->axisRect()->height();
+    ap->yAxis->rescale(true);
+    ap->yAxis->scaleRange((axis_pixels + (pixel_pad * 2)) / axis_pixels, ap->yAxis->range().center());
+
+    ap->replot();
+}
+
 void RtpPlayerDialog::playFinished(RtpAudioStream *stream)
 {
     playing_streams_.removeOne(stream);
@@ -1287,7 +1318,12 @@ void RtpPlayerDialog::on_actionRemoveStream_triggered()
 
         delete ti;
     }
-    ui->audioPlot->replot();
+    // TODO: Recalculate legend
+    // - Graphs used for legend could be removed above and we must add new
+    // - If no legend is required, it should be removed
+
+    // Redraw existing waveforms and rescale Y axis
+    updateGraphs();
 
     updateWidgets();
 }

ui/qt/rtp_player_dialog.h

@@ -97,6 +97,7 @@ private slots:
     void plotClicked(QCPAbstractPlottable *plottable, int dataIndex, QMouseEvent *event);
     void updateHintLabel();
     void resetXAxis();
+    void updateGraphs();
     void playFinished(RtpAudioStream *stream);
 
     void setPlayPosition(double secs);

ui/rtp_stream.h

@@ -134,6 +134,9 @@ gboolean rtpstream_save(rtpstream_tapinfo_t *tapinfo, capture_file *cap_file, rt
 */
 void rtpstream_mark(rtpstream_tapinfo_t *tapinfo, capture_file *cap_file, rtpstream_info_t* stream_fwd, rtpstream_info_t* stream_rev);
 
+/* Constant based on fix for bug 4119/5902: don't insert too many silence
+ * frames.
+ */
 #define MAX_SILENCE_FRAMES 14400000
 
 #ifdef __cplusplus