Android: Fixed bug where the left/right channel would have the same w…

…ave data. The problem was the 32-bit integers coming out of BASS.NET were actually combining left/right values in the same integer (low-word/high-word).

Related to issue #406.

MPfm/MPfm.Android/Classes/Controls/OutputMeterView.cs

@@ -211,11 +211,7 @@ public override void Draw(global::Android.Graphics.Canvas canvas)
             // Get bar height -- If value = -100 then 0. If value = 0 then = 100. if value = 10 then = 110.
             //float barHeight = scaleMultiplier * (maxDB + 100);
 
-            //// Draw 0db line
-            //CoreGraphicsHelper.DrawLine(context, new List<PointF>(){
-            //    new PointF(0, 4), 
-            //    new PointF(Bounds.Width, 4)
-            //}, _color0dBLine, 1, false, false);
+            // Draw 0db line
             var paintLine = new Paint {
                 AntiAlias = true,
                 Color = _color0dBLine
@@ -307,25 +303,15 @@ public override void Draw(global::Android.Graphics.Canvas canvas)
 
             // Draw peak line
             float rightHeight = Height - (peakRightDB + 100);
-            canvas.DrawLine(barWidth, leftHeight, barWidth * 2, rightHeight, paintPeakLine);
+            canvas.DrawLine(barWidth, rightHeight, barWidth * 2, rightHeight, paintPeakLine);
 
             // Draw number of db      
             strDB = peakRightDB.ToString("00.0").Replace(",", ".");
             if (maxRightDB == -100.0f)
                 strDB = "-inf";
 
-            //// Draw number of decibels (with font shadow to make it easier to read)                
-            //sizeString = CoreGraphicsHelper.MeasureText(context, strDB, "HelveticaNeue-Bold", 10);
-            //newX = ((barWidth - sizeString.Width) / 2) + barWidth;
-            ////            rectBackgroundText = new RectangleF(newX, Bounds.Height - sizeString.Height - 4, sizeString.Width, sizeString.Height);
-            ////            rectBackgroundText.Inflate(new SizeF(2, 0));
-            ////            CoreGraphicsHelper.FillRect(context, rectBackgroundText, new CGColor(0.1f, 0.1f, 0.1f, 0.25f));
-            //CoreGraphicsHelper.DrawTextAtPoint(context, new PointF(newX + 1, Bounds.Height - sizeString.Height - 4), strDB, "HelveticaNeue-CondensedBold", 10, new CGColor(0.1f, 0.1f, 0.1f, 0.2f));
-            //CoreGraphicsHelper.DrawTextAtPoint(context, new PointF(newX, Bounds.Height - sizeString.Height - 4 - 1), strDB, "HelveticaNeue-CondensedBold", 10, new CGColor(1, 1, 1));
-
             rectText = new Rect();
             paintText.GetTextBounds(strDB, 0, strDB.Length, rectText);
-            //int newX = (barWidth - rectText.Width()) / 2;
             newX = ((barWidth - rectText.Width()) / 2) + barWidth;
             canvas.DrawText(strDB, newX, Height - rectText.Height() - 4 - 1, paintText);
         }

MPfm/MPfm.MVP/Presenters/EqualizerPresetsPresenter.cs

@@ -136,8 +136,8 @@ private void HandleOutputMeterTimerElapsed(object sender, object eventArgs)
                     for (int a = 0; a < data.Item1.Length; a++)
                     {
                         // The values are already negative to positive, it's just a matter of dividing the value by the max value to get it to -1/+1.
-                        left[a] = (float)data.Item1[a] / (float)Int32.MaxValue;
-                        right[a] = (float)data.Item2[a] / (float)Int32.MaxValue;
+                        left[a] = (float)data.Item1[a] / (float)Int16.MaxValue;
+                        right[a] = (float)data.Item2[a] / (float)Int16.MaxValue;
                         //Console.WriteLine("EQPresetPresenter - a: {0} value: {1} newValue: {2}", a, data.Item1[a], left[a]);
                     }
 

MPfm/MPfm.MVP/Services/PlayerService.cs

@@ -151,29 +151,25 @@ public void PlayerCommandMessageReceived(PlayerCommandMessage m)
             int[] sampleData = new int[l4];
             int length = _player.GetMixerData(lengthToFetch, sampleData);
 
-            // as less data might be returned by BASS_ChannelGetData as requested
+            // From BASS.NET API: Note: an int is 32-bit meaning if we expect to receive 16-bit data stereo a single int value will contain 2 x 16-bit, so a full stereo pair of data
             l4 = length / 4;
             int[] left = new int[l4 / 2];
             int[] right = new int[l4 / 2];
             for (int a = 0; a < l4; a++)
             {
-                int absLevel = Math.Abs(sampleData[a]);
+                int leftValue = Base.LowWord(sampleData[a]);
+                int rightValue = Base.HighWord(sampleData[a]);
 
-                // decide on L/R channel
-                if (a % 2 == 0)
-                {
-                    // Left channel
-                    left[a / 2] = sampleData[a];
-                    if (absLevel > maxL)
-                        maxL = absLevel;
-                }
-                else
-                {
-                    // Right channel
-                    right[a / 2] = sampleData[a];
-                    if (absLevel > maxR)
-                        maxR = absLevel;
-                }
+                int absLevelLeft = Math.Abs(leftValue);
+                int absLevelRight = Math.Abs(rightValue);
+
+                left[a/2] = leftValue;
+                if (absLevelLeft > maxL)
+                    maxL = absLevelLeft;
+
+                right[a/2] = rightValue;
+                if (absLevelRight > maxR)
+                    maxR = absLevelRight;
             }
 
             //            // Get min max info from wave block

MPfm/MPfm.Player/Player.cs

@@ -1342,6 +1342,7 @@ public long Seconds2Bytes(double value)
         /// <param name="sampleData">Sample data</param>
         public int GetMixerData(int length, int[] sampleData)
         {
+            // NOTE: Do *NOT* try to use the GetData/GetMixerData with short/Int16 array because it crashes under Xamarin.Android.
             int dataLength;
             if (Device.DriverType != DriverType.DirectSound)
                 dataLength = _fxChannel.GetMixerData(sampleData, length);

MPfm/MPfm.Sound/BassNetWrapper/Base.cs

@@ -17,6 +17,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Security.Policy;
 using MPfm.Core;
 using Un4seen.Bass;
 using Un4seen.Bass.AddOn.Fx;
@@ -368,6 +369,26 @@ public static Double LevelToDB_16Bit(double level)
             return Conversion.LevelToDB(level, 65535);
         }
 
+        /// <summary>
+        /// Extracts the low word (16-bit) out of a 32-bit integer.
+        /// </summary>
+        /// <param name="dWord">32-bit integer</param>
+        /// <returns>Low word (16-bit)</returns>
+        public static short LowWord(int dWord)
+        {
+            return Utils.LowWord(dWord);
+        }
+
+        /// <summary>
+        /// Extracts the high word (16-bit) out of a 32-bit integer.
+        /// </summary>
+        /// <param name="dWord">32-bit integer</param>
+        /// <returns>High word (16-bit)</returns>
+        public static short HighWord(int dWord)
+        {
+            return Utils.HighWord(dWord);
+        }
+
         #endregion
 
         #region Error Management
@@ -390,5 +411,6 @@ public static void CheckForError()
         }
 
         #endregion
+
     }
 }