Fix generating audio files that are a teeny tiny bit longer than the original (#16)

* Respect SampleCount metadata when rebuilding ogg files

Since Vorbis blocks are always one of two possible sizes, a Vorbis
container needs some other field to hold the actual number of samples in
the audio file. This change essentially copies the SampleCount FSB
metadata field to the ogg output.

* Respect SampleCount metadata when rebuilding wav files

FSB PCM files appear to be padded with zeroes, meaning the correct
number of samples to copy is the SampleCount value instead of just the
rest of the file.

Author: tbodt

Fmod5Sharp.Tests/Fmod5Sharp.Tests.csproj

@@ -17,6 +17,8 @@
 
     <ItemGroup>
         <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.9.4" />
+        <PackageReference Include="NAudio.Core" Version="2.1.0"/>
+        <PackageReference Include="NVorbis" Version="0.10.5" />
         <PackageReference Include="xunit" Version="2.4.1" />
         <PackageReference Include="xunit.runner.visualstudio" Version="2.4.3">
             <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>

Fmod5Sharp.Tests/Fmod5SharpPcmTests.cs

@@ -1,5 +1,7 @@
 using Fmod5Sharp.CodecRebuilders;
 using Fmod5Sharp.FmodTypes;
+using NAudio.Wave;
+using System.IO;
 using Xunit;
 
 namespace Fmod5Sharp.Tests
@@ -23,9 +25,11 @@ public void PcmFilesCanBeReconstructed()
 
             var fsb = FsbLoader.LoadFsbFromByteArray(rawData);
 
-            var wavFile = FmodPcmRebuilder.Rebuild(fsb.Samples[0], fsb.Header.AudioType);
-            
-            Assert.NotEmpty(wavFile);
+            var sample = fsb.Samples[0];
+
+            var wavFile = FmodPcmRebuilder.Rebuild(sample, fsb.Header.AudioType);
+
+            Assert.Equal(sample.Metadata.SampleCount, new WaveFileReader(new MemoryStream(wavFile)).SampleCount);
         }
     }
 }

Fmod5Sharp.Tests/Fmod5SharpVorbisTests.cs

@@ -1,4 +1,7 @@
 using Fmod5Sharp.CodecRebuilders;
+using Fmod5Sharp.FmodTypes;
+using NVorbis;
+using System.IO;
 using Xunit;
 
 namespace Fmod5Sharp.Tests
@@ -27,9 +30,7 @@ public void VorbisAudioCanBeRestoredWithoutExceptions()
 
             var oggBytes = FmodVorbisRebuilder.RebuildOggFile(sample);
 
-            Assert.NotEmpty(oggBytes);
-            
-            //Cannot assert on length output bytes because it changes with the version of libvorbis you use.
+            CheckSampleCount(sample, oggBytes);
         }
 
         [Fact]
@@ -43,7 +44,7 @@ public void LongerFilesWorkToo()
 
             var oggBytes = FmodVorbisRebuilder.RebuildOggFile(sample);
 
-            Assert.NotEmpty(oggBytes);
+            CheckSampleCount(sample, oggBytes);
         }
 
         [Fact]
@@ -57,7 +58,7 @@ public void PreviouslyUnrecoverableVorbisFilesWorkWithOurCustomRebuilder()
 
             var oggBytes = FmodVorbisRebuilder.RebuildOggFile(sample);
 
-            Assert.NotEmpty(oggBytes);
+            CheckSampleCount(sample, oggBytes);
         }
 
         [Fact]
@@ -71,7 +72,12 @@ public void VorbisFilesThatPreviouslyThrewExceptionsDoNot()
 
             var oggBytes = FmodVorbisRebuilder.RebuildOggFile(sample);
 
-            Assert.NotEmpty(oggBytes);
+            CheckSampleCount(sample, oggBytes);
+        }
+
+        private bool CheckSampleCount(FmodSample sample, byte[] oggBytes)
+        {
+            Assert.Equal(sample.Metadata.SampleCount, new VorbisReader(new MemoryStream(oggBytes)).TotalSamples);
         }
     }
 }

Fmod5Sharp/CodecRebuilders/FmodPcmRebuilder.cs

@@ -1,6 +1,6 @@
-using System.IO;
-using Fmod5Sharp.FmodTypes;
+using Fmod5Sharp.FmodTypes;
 using NAudio.Wave;
+using System.IO;
 
 namespace Fmod5Sharp.CodecRebuilders
 {
@@ -28,7 +28,7 @@ public static byte[] Rebuild(FmodSample sample, FmodAudioType type)
             using var stream = new MemoryStream();
             using var writer = new WaveFileWriter(stream, format);
 
-            writer.Write(sample.SampleBytes, 0, sample.SampleBytes.Length);
+            writer.Write(sample.SampleBytes, 0, numChannels * width * (int) sample.Metadata.SampleCount);
 
             return stream.GetBuffer();
         }

Fmod5Sharp/CodecRebuilders/FmodVorbisRebuilder.cs

@@ -60,7 +60,7 @@ public static byte[] RebuildOggFile(FmodSample sample)
 
             oggStream.FlushAndCopyTo(outputStream, true);
 
-            CopySampleData(vorbisData, sample.SampleBytes, oggStream, outputStream);
+            CopySampleData(vorbisData, sample.Metadata.SampleCount, sample.SampleBytes, oggStream, outputStream);
 
             return outputStream.ToArray();
         }
@@ -130,16 +130,16 @@ private static OggPacket BuildCommentPacket(string vendor)
             return new(oggMs.ToArray(), false, 0, 1);
         }
 
-        private static void CopySampleData(FmodVorbisData vorbisData, byte[] sampleBytes, OggStream oggStream, Stream outputStream)
+        private static void CopySampleData(FmodVorbisData vorbisData, uint sampleCount, byte[] sampleBytes, OggStream oggStream, Stream outputStream)
         {
             using var inputStream = new MemoryStream(sampleBytes);
             using var inputReader = new BinaryReader(inputStream);
 
             ReadSamplePackets(inputReader, out var packetLength, out var packets);
 
             var packetNum = 1;
-            var granulePos = 0;
-            var previousBlockSize = 0;
+            uint granulePos = 0;
+            uint previousBlockSize = 0;
 
             var finalPacketNum = packetLength.Count - 1;
 
@@ -158,16 +158,24 @@ private static void CopySampleData(FmodVorbisData vorbisData, byte[] sampleBytes
                 else
                     granulePos += (blockSize + previousBlockSize) / 4;
 
+                //Make sure to end the stream once we reach the sample count in the metadata.
+                if (granulePos > sampleCount)
+                    granulePos = sampleCount;
+
                 //Set previous block size
                 previousBlockSize = blockSize;
 
                 //Write the packet to the stream
-                oggStream.PacketIn(new(packet, isLast, granulePos,  packetNum));
+                oggStream.PacketIn(new(packet, isLast, (int) granulePos, packetNum));
                 oggStream.FlushAndCopyTo(outputStream, isLast);
+
+                //Early end to the stream if this is going past the sample count in the metadata.
+                if (granulePos == sampleCount)
+                    break;
             }
         }
 
-        private static void ReadSamplePackets(BinaryReader inputReader, out List<int> packetLengths, out List<byte[]> packets)
+        private static void ReadSamplePackets(BinaryReader inputReader, out List<ushort> packetLengths, out List<byte[]> packets)
         {
             packetLengths = new();
             packets = new();

Fmod5Sharp/FmodTypes/FmodSampleMetadata.cs

@@ -9,12 +9,12 @@ public class FmodSampleMetadata : IBinaryReadable
 	{
 		internal bool HasAnyChunks;
 		internal uint FrequencyId;
-		internal ulong DataOffset;
+		internal uint DataOffset;
 		internal List<FmodSampleChunk> Chunks = new();
 		internal int NumChannels;
 
 		public bool IsStereo;
-		public ulong SampleCount;
+		public uint SampleCount;
 
 		public int Frequency => FsbLoader.Frequencies.TryGetValue(FrequencyId, out var actualFrequency) ? actualFrequency : (int)FrequencyId; //If set by FREQUENCY chunk, id is actual frequency
 		public uint Channels => (uint)NumChannels;
@@ -38,8 +38,8 @@ void IBinaryReadable.Read(BinaryReader reader)
 
 			IsStereo = NumChannels == 2;
 
-			DataOffset = encoded.Bits(7, 27) * 32;
-			SampleCount = encoded.Bits(34, 30);
+			DataOffset = (uint) encoded.Bits(7, 27) * 32;
+			SampleCount = (uint) encoded.Bits(34, 30);
 		}
 	}
 }

Fmod5Sharp/Util/FmodVorbisData.cs

@@ -59,7 +59,7 @@ internal void InitBlockFlags()
         }).ToArray();
     }
 
-    public int GetPacketBlockSize(byte[] packetBytes)
+    public uint GetPacketBlockSize(byte[] packetBytes)
     {
         var bitStream = new BitStream(packetBytes);