feat: next output frame rate

CHANGELOG.md

@@ -10,6 +10,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
   - Add `mpeg2video` encoder support (software, some Intel QSV and Intel VAAPI devices)
   - Add song playback support, using legacy-generated background image and text
     - Song Video Mode `With Progress` is not supported yet; these songs play without a progress bar
+  - Support FFmpeg Profile `Normalize Frame Rate`
+    - As with the legacy engine, the target is the lowest frame rate above 23 fps among the channel's scheduled items
+    - Frames are dropped or duplicated to reach the target, instead of blended
+    - With video copy, only items already at the target rate are copied; others are transcoded
 - Add `Deep Scan Library` button to local libraries
   - A deep scan re-probes every file and refreshes all metadata and artwork, even when files appear unchanged
   - This forces a refresh of e.g. NFO files or posters that were edited without changing their modified time

ErsatzTV.Application/Streaming/ChannelConfigConverter.cs

@@ -1,3 +1,4 @@
+using System.Globalization;
 using System.IO.Abstractions;
 using ErsatzTV.Application.Channels;
 using ErsatzTV.Application.FFmpegProfiles;
@@ -6,18 +7,20 @@
 using ErsatzTV.Core.FFmpeg;
 using ErsatzTV.Core.Interfaces.Repositories;
 using ErsatzTV.Core.Next.Config;
+using ErsatzTV.FFmpeg;
 using Subtitle = ErsatzTV.Core.Next.Config.Subtitle;
 
 namespace ErsatzTV.Application.Streaming;
 
 public class ChannelConfigConverter(IConfigElementRepository configElementRepository, IFileSystem fileSystem)
     : IChannelConfigConverter
 {
-    public static readonly string ChannelConfigVersion = "https://ersatztv.org/channel/version/0.1.0";
+    public static readonly string ChannelConfigVersion = "https://ersatztv.org/channel/version/0.1.1";
 
     public async Task<ChannelConfig> ToNext(
         ChannelViewModel channel,
         FFmpegProfileViewModel ffmpegProfile,
+        Option<FrameRate> targetFramerate,
         CancellationToken cancellationToken)
     {
         var ffmpeg = new Ffmpeg
@@ -147,6 +150,11 @@ public async Task<ChannelConfig> ToNext(
             }
         };
 
+        foreach (string frameRate in targetFramerate.Bind(ToNextFrameRate))
+        {
+            videoNormalization.FrameRate = frameRate;
+        }
+
         var subtitleNormalization = new Subtitle
         {
             Mode = channel.NextEngineTextSubtitleMode switch
@@ -179,4 +187,45 @@ public async Task<ChannelConfig> ToNext(
             }
         };
     }
+
+    private const int MaxNextFrameRate = 240;
+
+    // reject decimals
+    public static Option<string> ToNextFrameRate(FrameRate frameRate)
+    {
+        string value = frameRate.RFrameRate.Trim();
+
+        string[] parts = value.Split('/');
+        if (parts.Length <= 2 && parts.All(p => p.Length > 0 && p.All(char.IsAsciiDigit)))
+        {
+            if (!long.TryParse(parts[0], out long num) ||
+                !long.TryParse(parts.Length == 2 ? parts[1] : "1", out long den) ||
+                num == 0 || den == 0 || num < den || num > den * MaxNextFrameRate)
+            {
+                return Option<string>.None;
+            }
+
+            return value;
+        }
+
+        if (!double.TryParse(value, NumberStyles.Float, CultureInfo.InvariantCulture, out double rate) ||
+            rate < 1 || rate > MaxNextFrameRate)
+        {
+            return Option<string>.None;
+        }
+
+        double integer = Math.Round(rate);
+        if (Math.Abs(rate - integer) < 0.001)
+        {
+            return ((long)integer).ToString(CultureInfo.InvariantCulture);
+        }
+
+        double ntsc = Math.Round(rate * 1.001);
+        if (Math.Abs(rate * 1.001 - ntsc) < 0.005)
+        {
+            return $"{(long)ntsc * 1000}/1001";
+        }
+
+        return $"{(long)Math.Round(rate * 1000)}/1000";
+    }
 }

ErsatzTV.Application/Streaming/Commands/StartFFmpegNextSessionHandler.cs

@@ -12,6 +12,7 @@
 using ErsatzTV.Core.Interfaces.Metadata;
 using ErsatzTV.Core.Interfaces.Repositories;
 using ErsatzTV.Core.Next.Config;
+using ErsatzTV.FFmpeg;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
 using Microsoft.Extensions.Logging;
@@ -68,9 +69,9 @@ private async Task<Either<BaseError, IHlsSessionWorker>> CreateWorker(
 
         Option<TimeSpan> idleTimeout = Option<TimeSpan>.None;
 
-        // Option<FrameRate> targetFramerate = await mediator.Send(
-        //     new GetChannelFramerate(request.ChannelNumber),
-        //     cancellationToken);
+        Option<FrameRate> targetFramerate = await mediator.Send(
+            new GetChannelFramerate(request.ChannelNumber),
+            cancellationToken);
 
         Option<ChannelViewModel> maybeChannel =
             await mediator.Send(new GetChannelByNumber(request.ChannelNumber), cancellationToken);
@@ -105,7 +106,11 @@ private async Task<Either<BaseError, IHlsSessionWorker>> CreateWorker(
 
         PrepareTranscodeFolder(request.ChannelNumber);
 
-        ChannelConfig config = await channelConfigConverter.ToNext(channel, ffmpegProfile, cancellationToken);
+        ChannelConfig config = await channelConfigConverter.ToNext(
+            channel,
+            ffmpegProfile,
+            targetFramerate,
+            cancellationToken);
 
         NextSessionWorker worker = new NextSessionWorker(
             channelBinary,

ErsatzTV.Application/Streaming/IChannelConfigConverter.cs

@@ -1,5 +1,6 @@
 using ErsatzTV.Application.Channels;
 using ErsatzTV.Application.FFmpegProfiles;
+using ErsatzTV.FFmpeg;
 
 namespace ErsatzTV.Application.Streaming;
 
@@ -8,5 +9,6 @@ public interface IChannelConfigConverter
     Task<Core.Next.Config.ChannelConfig> ToNext(
         ChannelViewModel channel,
         FFmpegProfileViewModel ffmpegProfile,
+        Option<FrameRate> targetFramerate,
         CancellationToken cancellationToken);
 }

ErsatzTV.Application/Troubleshooting/Commands/PrepareTroubleshootingPlaybackHandler.cs

@@ -366,6 +366,7 @@ private async Task<Either<BaseError, PlayoutItemResult>> GetNextProcess(
         ChannelConfig config = await channelConfigConverter.ToNext(
             Channels.Mapper.ProjectToViewModel(channel, playoutCount: 0),
             FFmpegProfiles.Mapper.ProjectToViewModel(ffmpegProfile),
+            Option<FrameRate>.None,
             cancellationToken);
 
         config.Playout.VirtualStart = start.ToString("yyyy-MM-dd'T'HH:mm:ss.fffK", CultureInfo.InvariantCulture);

ErsatzTV.Core/Next/Config/ChannelConfig.cs

@@ -204,6 +204,14 @@ public partial class Video
         [JsonPropertyName("format")]
         public VideoFormat? Format { get; set; }
 
+        /// <summary>
+        /// Output frame rate, `N` or `N/D` (e.g. `25`, `30000/1001`).
+        /// Frames are dropped or repeated to match it.
+        /// In `copy` mode, only items at this rate are copied. Unset keeps the source rate.
+        /// </summary>
+        [JsonPropertyName("frame_rate")]
+        public string? FrameRate { get; set; }
+
         [JsonPropertyName("height")]
         public long? Height { get; set; }
 

ErsatzTV.Tests/Streaming/ChannelConfigConverterTests.cs

@@ -1,11 +1,11 @@
-using System.IO.Abstractions;
 using ErsatzTV.Application.Channels;
 using ErsatzTV.Application.FFmpegProfiles;
 using ErsatzTV.Application.Streaming;
 using ErsatzTV.Core.Domain;
 using ErsatzTV.Core.FFmpeg;
 using ErsatzTV.Core.Interfaces.Repositories;
 using ErsatzTV.Core.Next.Config;
+using ErsatzTV.FFmpeg;
 using LanguageExt;
 using NUnit.Framework;
 using Testably.Abstractions;
@@ -131,9 +131,52 @@ public async Task Transcode_profile_should_transcode()
         config.Normalization.Video.Mode.ShouldBe(StreamMode.Transcode);
     }
 
+    [Test]
+    public async Task No_target_framerate_should_pass_source_rate_through()
+    {
+        ChannelConfig config = await Convert(Profile);
+
+        config.Normalization.Video.FrameRate.ShouldBeNull();
+    }
+
+    [Test]
+    public async Task Target_framerate_should_set_frame_rate()
+    {
+        ChannelConfig config = await Convert(Profile, new FrameRate("24000/1001"));
+
+        config.Normalization.Video.FrameRate.ShouldBe("24000/1001");
+    }
+
+    [TestCase("24000/1001", "24000/1001")]
+    [TestCase("25/1", "25/1")]
+    [TestCase("30", "30")]
+    [TestCase("23.976", "24000/1001")]
+    [TestCase("23.98", "24000/1001")]
+    [TestCase("29.97", "30000/1001")]
+    [TestCase("59.94", "60000/1001")]
+    [TestCase("25.00", "25")]
+    [TestCase("12.5", "12500/1000")]
+    public void ToNextFrameRate_should_convert_to_rational(string input, string expected) =>
+        ChannelConfigConverter.ToNextFrameRate(new FrameRate(input)).ShouldBe(Option<string>.Some(expected));
+
+    [TestCase("")]
+    [TestCase("0/0")]
+    [TestCase("30/0")]
+    [TestCase("1/2")]
+    [TestCase("0.5")]
+    [TestCase("241")]
+    [TestCase("1000/1")]
+    [TestCase("abc")]
+    [TestCase("-30")]
+    public void ToNextFrameRate_should_reject_unusable_rates(string input) =>
+        ChannelConfigConverter.ToNextFrameRate(new FrameRate(input)).IsNone.ShouldBeTrue();
+
     private static Task<ChannelConfig> Convert(FFmpegProfileViewModel profile) =>
+        Convert(profile, Option<FrameRate>.None);
+
+    private static Task<ChannelConfig> Convert(FFmpegProfileViewModel profile, Option<FrameRate> targetFramerate) =>
         new ChannelConfigConverter(new EmptyConfigElementRepository(), new RealFileSystem())
-            .ToNext(Channel, profile, CancellationToken.None);
+            .ToNext(Channel, profile, targetFramerate, CancellationToken.None);
 
     private sealed class EmptyConfigElementRepository : IConfigElementRepository
     {