#7 some untested codes for converting mp3 to ogg for poem narrations

RMuseum/RMuseum.csproj

@@ -19,6 +19,8 @@
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
     <PackageReference Include="MySql.Data" Version="8.0.21" />
+    <PackageReference Include="NAudio" Version="1.10.0" />
+    <PackageReference Include="OggVorbisEncoder" Version="1.1.0" />
     <PackageReference Include="Swashbuckle.AspNetCore" Version="5.2.1" />
     <PackageReference Include="Swashbuckle.AspNetCore.Annotations" Version="5.2.1" />
     <PackageReference Include="Swashbuckle.AspNetCore.Filters" Version="5.0.2" />

RMuseum/Services/Implementation/AudioNarrationService.cs

@@ -4,6 +4,8 @@ using Microsoft.AspNetCore.Http;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Configuration;
 using MySql.Data.MySqlClient;
+using NAudio.Wave;
+using OggVorbisEncoder;
 using RMuseum.DbContext;
 using RMuseum.Models.GanjoorAudio;
 using RMuseum.Models.GanjoorAudio.ViewModels;
@@ -282,6 +284,14 @@ namespace RMuseum.Services.Implementation
                                         {
                                             //here we should produce and save ogg file
 
+                                            using(Mp3FileReader mp3FileReader = new Mp3FileReader(mp3file.FilePath))
+                                            {
+                                                byte[] samples = new byte[mp3FileReader.Length];
+                                                await mp3FileReader.ReadAsync(samples, 0, (int)mp3FileReader.Length);
+                                                var oggBytes = ConvertRawPCMFile(mp3FileReader.Mp3WaveFormat.SampleRate, mp3FileReader.Mp3WaveFormat.Channels, samples, PCMSample.EightBit, mp3FileReader.Mp3WaveFormat.SampleRate, mp3FileReader.Mp3WaveFormat.Channels);
+                                                File.WriteAllBytes(Path.Combine(Path.GetDirectoryName(mp3file.FilePath), $"{Path.GetFileNameWithoutExtension(mp3file.FilePath)}.ogg") , oggBytes);
+                                            }
+
                                             session.UploadedFiles.Where(f => f.Id == file.Id).SingleOrDefault().ProcessResultMsg = "";
                                             session.UploadedFiles.Where(f => f.Id == file.Id).SingleOrDefault().ProcessResult = true;
                                             session.UploadedFiles.Where(f => f.Id == mp3file.Id).SingleOrDefault().ProcessResultMsg = "";
@@ -313,7 +323,137 @@ namespace RMuseum.Services.Implementation
             }
         }
 
-        
+        enum PCMSample : int
+        {
+            EightBit = 1,
+            SixteenBit = 2
+        }
+
+        private static byte[] ConvertRawPCMFile(int OutputSampleRate, int OutputChannels, byte[] PCMSamples, PCMSample PCMSampleSize, int PCMSampleRate, int PCMChannels)
+        {
+            int NumPCMSamples = (PCMSamples.Length / (int)PCMSampleSize / PCMChannels);
+            float PCMDuraton = NumPCMSamples / (float)PCMSampleRate;
+
+            int NumOutputSamples = (int)(PCMDuraton * OutputSampleRate);
+            //Ensure that samble buffer is aligned to write chunk size
+            NumOutputSamples = (NumOutputSamples / WriteBufferSize) * WriteBufferSize;
+
+            float[][] OutSamples = new float[OutputChannels][];
+
+            for (int ch = 0; ch < OutputChannels; ch++)
+                OutSamples[ch] = new float[NumOutputSamples];
+
+            for (int sampleNumber = 0; sampleNumber < NumOutputSamples; sampleNumber++)
+            {
+                float rawSample = 0.0f;
+
+                for (int ch = 0; ch < OutputChannels; ch++)
+                {
+                    int sampleIndex = (sampleNumber * PCMChannels) * (int)PCMSampleSize;
+
+                    if (ch < PCMChannels) sampleIndex += (ch * (int)PCMSampleSize);
+
+                    switch (PCMSampleSize)
+                    {
+                        case PCMSample.EightBit:
+                            rawSample = ByteToSample(PCMSamples[sampleIndex]);
+                            break;
+                        case PCMSample.SixteenBit:
+                            rawSample = ShortToSample((short)(PCMSamples[sampleIndex + 1] << 8 | PCMSamples[sampleIndex]));
+                            break;
+                    }
+
+                    OutSamples[ch][sampleNumber] = rawSample;
+                }
+            }
+
+            return GenerateFile(OutSamples, OutputSampleRate, OutputChannels);
+        }
+
+        private static float ByteToSample(short pcmValue)
+        {
+            return pcmValue / 128f;
+        }
+
+        private static float ShortToSample(short pcmValue)
+        {
+            return pcmValue / 32768f;
+        }
+
+        private static byte[] GenerateFile(float[][] FloatSamples, int SampleRate, int Channels)
+        {
+            using (MemoryStream outputData = new MemoryStream())
+            {
+                // Stores all the static vorbis bitstream settings
+                var info = VorbisInfo.InitVariableBitRate(Channels, SampleRate, 0.5f);
+
+                // set up our packet->stream encoder
+                var serial = new Random().Next();
+                var oggStream = new OggStream(serial);
+
+                // =========================================================
+                // HEADER
+                // =========================================================
+                // Vorbis streams begin with three headers; the initial header (with
+                // most of the codec setup parameters) which is mandated by the Ogg
+                // bitstream spec.  The second header holds any comment fields.  The
+                // third header holds the bitstream codebook.
+                var headerBuilder = new HeaderPacketBuilder();
+
+                var comments = new Comments();
+                comments.AddTag("ARTIST", "TEST");
+
+                var infoPacket = headerBuilder.BuildInfoPacket(info);
+                var commentsPacket = headerBuilder.BuildCommentsPacket(comments);
+                var booksPacket = headerBuilder.BuildBooksPacket(info);
+
+                oggStream.PacketIn(infoPacket);
+                oggStream.PacketIn(commentsPacket);
+                oggStream.PacketIn(booksPacket);
+
+                // Flush to force audio data onto its own page per the spec
+                FlushPages(oggStream, outputData, true);
+
+                // =========================================================
+                // BODY (Audio Data)
+                // =========================================================
+                var processingState = ProcessingState.Create(info);
+
+                processingState.WriteData(FloatSamples, FloatSamples[0].Length);
+                for (int readIndex = 0; readIndex <= FloatSamples[0].Length; readIndex += WriteBufferSize)
+                {
+                   
+                    OggPacket packet;
+                    while (!oggStream.Finished
+                            && processingState.PacketOut(out packet))
+                    {
+                        oggStream.PacketIn(packet);
+
+                        FlushPages(oggStream, outputData, false);
+                    }
+                }
+
+                FlushPages(oggStream, outputData, true);
+
+                return outputData.ToArray();
+            }
+        }
+
+        private static void FlushPages(OggStream oggStream, Stream Output, bool Force)
+        {
+            OggPage page;
+            while (oggStream.PageOut(out page, Force))
+            {
+                Output.Write(page.Header, 0, page.Header.Length);
+                Output.Write(page.Body, 0, page.Body.Length);
+            }
+        }
+
+        private static int WriteBufferSize = 512;
+        private static readonly int[] SampleRates = { 8000, 11025, 16000, 22050, 32000, 44100 };
+
+
+
         /// <summary>
         /// Get Upload Session (including files)
         /// </summary>