Redo clips api

NostrStreamer/Services/Clips/ClipGenerator.cs

@@ -1,5 +1,5 @@
+using System.Text.RegularExpressions;
 using FFMpegCore;
-using NostrStreamer.Database;
 
 namespace NostrStreamer.Services.Clips;
 
@@ -7,28 +7,56 @@ public class ClipGenerator
 {
     private readonly ILogger<ClipGenerator> _logger;
     private readonly Config _config;
+    private readonly HttpClient _client;
 
-    public ClipGenerator(ILogger<ClipGenerator> logger, Config config)
+    public ClipGenerator(ILogger<ClipGenerator> logger, Config config, HttpClient client)
     {
         _logger = logger;
         _config = config;
+        _client = client;
     }
 
-    public async Task<string> GenerateClip(UserStream stream)
+    public async Task<string> CreateClipFromSegments(List<ClipSegment> segments, float start, float length)
     {
-        const int clipLength = 20;
         var path = Path.ChangeExtension(Path.GetTempFileName(), ".mp4");
         var cmd = FFMpegArguments
-            .FromUrlInput(new Uri(_config.DataHost, $"stream/{stream.Id}.m3u8"),
-                inOpt =>
-                {
-                    inOpt.WithCustomArgument($"-ss -{clipLength}");
-                })
-            .OutputToFile(path, true, o => { o.WithDuration(TimeSpan.FromSeconds(clipLength)); })
+            .FromConcatInput(segments.Select(a => a.GetPath()),
+                inOpt => { inOpt.Seek(TimeSpan.FromSeconds(start)); })
+            .OutputToFile(path, true, o => { o.WithDuration(TimeSpan.FromSeconds(length)); })
             .CancellableThrough(new CancellationTokenSource(TimeSpan.FromSeconds(60)).Token);
-        
+
         _logger.LogInformation("Running command {cmd}", cmd.Arguments);
         await cmd.ProcessAsynchronously();
         return path;
     }
+
+    public async Task<List<ClipSegment>> GetClipSegments(Guid id)
+    {
+        var ret = new List<ClipSegment>();
+        var playlist = new Uri(_config.DataHost, $"stream/{id}.m3u8");
+
+        var rsp = await _client.GetStreamAsync(playlist);
+        using var sr = new StreamReader(rsp);
+        while (await sr.ReadLineAsync() is { } line)
+        {
+            if (line.StartsWith("#EXTINF"))
+            {
+                var trackPath = await sr.ReadLineAsync();
+                var seg = Regex.Match(trackPath!, @"-(\d+)\.ts");
+                var idx = int.Parse(seg.Groups[1].Value);
+                var clipSeg = new ClipSegment(id, idx);
+                var outPath = clipSeg.GetPath();
+                if (!File.Exists(outPath))
+                {
+                    var segStream = await _client.GetStreamAsync(new Uri(_config.DataHost, trackPath));
+                    await using var fsOut = new FileStream(outPath, FileMode.Create, FileAccess.ReadWrite);
+                    await segStream.CopyToAsync(fsOut);
+                }
+
+                ret.Add(clipSeg);
+            }
+        }
+
+        return ret;
+    }
 }

NostrStreamer/Services/Clips/IClipService.cs

@@ -2,7 +2,17 @@ namespace NostrStreamer.Services.Clips;
 
 public interface IClipService
 {
-    Task<ClipResult?> CreateClip(Guid streamId, string takenBy);
+    Task<List<ClipSegment>?> PrepareClip(Guid streamId);
+
+    Task<ClipResult?> MakeClip(string takenBy, List<ClipSegment> segments, float start, float length);
 }
 
 public record ClipResult(Uri Url);
+
+public record ClipSegment(Guid Id, int Index)
+{
+    public string GetPath()
+    {
+        return Path.Join(Path.GetTempPath(), Id.ToString(), $"{Index}.ts");
+    }
+}

NostrStreamer/Services/Clips/S3ClipService.cs

@@ -20,7 +20,7 @@ public class S3ClipService : IClipService
         _context = context;
     }
 
-    public async Task<ClipResult?> CreateClip(Guid streamId, string takenBy)
+    public async Task<List<ClipSegment>?> PrepareClip(Guid streamId)
     {
         var stream = await _context.Streams
             .Include(a => a.User)
@@ -32,12 +32,19 @@ public class S3ClipService : IClipService
             return default;
         }
 
-        var tmpClip = await _generator.GenerateClip(stream);
+        return await _generator.GetClipSegments(streamId);
+    }
 
+    public async Task<ClipResult?> MakeClip(string takenBy, List<ClipSegment> segments, float start, float length)
+    {
+        if (segments.Count == 0) return default;
+
+        var streamId = segments.First().Id;
+        var clip = await _generator.CreateClipFromSegments(segments, start, length);
         var clipId = Guid.NewGuid();
-        var s3Path = $"{stream.Id}/clips/{clipId}.mp4";
+        var s3Path = $"{streamId}/clips/{clipId}.mp4";
 
-        await using var fs = new FileStream(tmpClip, FileMode.Open, FileAccess.Read);
+        await using var fs = new FileStream(clip, FileMode.Open, FileAccess.Read);
         await _client.PutObjectAsync(new()
         {
             BucketName = _config.S3Store.BucketName,
@@ -67,7 +74,7 @@ public class S3ClipService : IClipService
         var clipObj = new UserStreamClip()
         {
             Id = clipId,
-            UserStreamId = stream.Id,
+            UserStreamId = streamId,
             TakenByPubkey = takenBy,
             Url = ub.Uri.ToString()
         };