Audio Transcoder

Application/Contracts/Infrastructure/IAudioTranscoder.cs

@@ -0,0 +1,9 @@
+using Ardalis.Result;
+
+namespace Musify.Application.Contracts.Infrastructure
+{
+    public interface IAudioTranscoder
+    {
+        Task<Result> TranscodeToDash(Stream audioStream, string folderName, CancellationToken cancellationToken);
+    }
+}

Infrastructure/Audio/AudioTranscoder.cs

@@ -0,0 +1,92 @@
+using Ardalis.Result;
+using Microsoft.Extensions.Logging;
+using Musify.Application.Contracts.Infrastructure;
+using Musify.Infrastructure.Configuration;
+using System.Diagnostics;
+
+namespace Musify.Infrastructure.Audio
+{
+    public class AudioTranscoder(ILogger<AudioTranscoder> logger, AudioTranscoderConfiguration transcoderConfiguration)
+        : IAudioTranscoder
+    {
+        const string FfmpegProcessName = "ffmpeg";
+
+        public async Task<Result> TranscodeToDash(Stream audioStream, string folderName, CancellationToken cancellationToken)
+        {
+            var workingDirectory = Path.Combine(transcoderConfiguration.Routes.WorkingDirectory, folderName);
+
+            try
+            {
+                Directory.CreateDirectory(workingDirectory);
+
+                using var process = new Process
+                {
+                    StartInfo = new ProcessStartInfo
+                    {
+                        FileName = FfmpegProcessName,
+                        WorkingDirectory = workingDirectory,
+                        Arguments = BuildDashArguments(workingDirectory),
+                        RedirectStandardInput = true,
+                        RedirectStandardOutput = true,
+                        RedirectStandardError = true,
+                        UseShellExecute = false,
+                        CreateNoWindow = true,
+                    }
+                };
+                process.Start();
+
+                if (audioStream.CanSeek)
+                    audioStream.Position = 0;
+                await audioStream.CopyToAsync(process.StandardInput.BaseStream, cancellationToken);
+                process.StandardInput.Close();
+
+                var errorTask = process.StandardError.ReadToEndAsync(cancellationToken);
+                var outputTask = process.StandardOutput.ReadToEndAsync(cancellationToken);
+
+                using var linkedCancellationTokens = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
+                linkedCancellationTokens.CancelAfter(transcoderConfiguration.TranscodingTimeout);
+                await process.WaitForExitAsync(linkedCancellationTokens.Token);
+
+                var standardError = await errorTask;
+                var standardOutput = await outputTask;
+
+                if (process.ExitCode != 0)
+                {
+                    logger.LogError("Audio transcoding to DASH format failed with exit code {ExitCode}. Standard Output: {StandardOutput}, Standard Error: {StandardError}", process.ExitCode, standardOutput, standardError);
+                    return Result.Error($"Audio transcoding failed with exit code {process.ExitCode}. See logs for details.");
+                }
+
+                logger.LogInformation("Audio transcoding to DASH format completed successfully. Uploading to storage...");
+                return Result.Success();
+            }
+            catch (Exception exception)
+            {
+                logger.LogError(exception, "An error occurred while transcoding audio to DASH format.");
+                return Result.Error(exception.Message);
+            }
+        }
+
+        static string BuildDashArguments(string outputDirectory)
+        {
+            var manifestPath = Path.Combine(outputDirectory, "manifest.mpd");
+
+            return "-y -hide_banner -loglevel error " +
+                   "-i pipe:0 " +
+                   "-vn " +
+                   "-map 0:a " +
+                   "-c:a aac " +
+                   "-b:a 128k " +
+                   "-ac 2 " +
+                   "-ar 48000 " +
+                   "-profile:a aac_low " +
+                   "-f dash " +
+                   "-seg_duration 4 " +
+                   "-streaming 1 " +
+                   "-use_template 1 " +
+                   "-use_timeline 0 " +
+                   "-init_seg_name \"init-stream$RepresentationID$.m4s\" " +
+                   "-media_seg_name \"chunk-stream$RepresentationID$-$Number$.m4s\" " +
+                   $"\"{manifestPath}\"";
+        }
+    }
+}

Infrastructure/Audio/AudioTranscoderDependencyInjection.cs

@@ -0,0 +1,14 @@
+using Microsoft.Extensions.DependencyInjection;
+using Musify.Application.Contracts.Infrastructure;
+
+namespace Musify.Infrastructure.Audio
+{
+    public static class AudioTranscoderDependencyInjection
+    {
+        public static IServiceCollection AddAudioTranscoder(this IServiceCollection serviceDescriptors)
+        {
+            serviceDescriptors.AddScoped<IAudioTranscoder, AudioTranscoder>();
+            return serviceDescriptors;
+        }
+    }
+}

Infrastructure/Configuration/AudioTranscoderConfiguration.cs

@@ -0,0 +1,22 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace Musify.Infrastructure.Configuration
+{
+#pragma warning disable CS8618
+    public class AudioTranscoderConfiguration
+    {
+        public const string SectionName = "AudioTranscoder";
+
+        [Required]
+        public AudioTranscoderRoutes Routes { get; set; } = new AudioTranscoderRoutes();
+
+        [Required]
+        public TimeSpan TranscodingTimeout { get; set; } = TimeSpan.FromMinutes(5);
+    }
+
+    public class AudioTranscoderRoutes
+    {
+        [Required]
+        public string WorkingDirectory { get; set; }
+    }
+}

Infrastructure/Configuration/ConfigurationDependencyInjection.cs

@@ -13,7 +13,8 @@ namespace Musify.Infrastructure.Configuration
                 .AddValidatedConfiguration<KeycloakConfiguration>(configuration, KeycloakConfiguration.SectionName)
                 .AddValidatedConfiguration<InfrastructureStorageConfiguration>(configuration, InfrastructureStorageConfiguration.SectionName)
                 .AddValidatedConfiguration<MessagingConfiguration>(configuration, MessagingConfiguration.SectionName)
-                .AddValidatedConfiguration<OpenTelemetryConfiguration>(configuration, OpenTelemetryConfiguration.SectionName);
+                .AddValidatedConfiguration<OpenTelemetryConfiguration>(configuration, OpenTelemetryConfiguration.SectionName)
+                .AddValidatedConfiguration<AudioTranscoderConfiguration>(configuration, AudioTranscoderConfiguration.SectionName);
 
             return serviceDescriptors;
         }

Infrastructure/InfrastructureDependencyInjection.cs

@@ -1,6 +1,7 @@
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
 using Musify.Application.Contracts.Infrastructure;
+using Musify.Infrastructure.Audio;
 using Musify.Infrastructure.Configuration;
 using Musify.Infrastructure.Identity;
 using Musify.Infrastructure.Messaging;
@@ -21,6 +22,7 @@ namespace Musify.Infrastructure
                 .AddKeycloakService(configuration)
                 .AddStorageHandler()
                 .AddPictureHandler()
+                .AddAudioTranscoder()
                 .AddInfrastructureOpenTelemetry()
                 .AddMassTransitClient()
                 .AddScoped<IEventBus, MassTransitEventBus>()
@@ -36,6 +38,7 @@ namespace Musify.Infrastructure
                 .AddDatabase(configuration)
                 .AddStorageHandler()
                 .AddPictureHandler()
+                .AddAudioTranscoder()
                 .AddInfrastructureOpenTelemetry()
                 .AddMassTransitConsumers()
                 .AddScoped<IEventBus, MassTransitEventBus>()