feat(quality): the creator sets the rate — per tier, persisted, clamped only at YouTube's floor

The tier table cannot know a creator's connection, so it should not pretend to. The Mbps box under the picker is theirs: the tier chooses geometry and frame rate, the box chooses bits. Stored per tier (`Video.Rate.<tier>`), so tuning 1080p60 does not touch 720p30, and none means "the shipped default" rather than zero. Clamped at the tier's YouTube minimum (`RateLadder`), because a target under it cannot hold the resolution; no ceiling otherwise, because a wrong guess is exactly what live step-down exists to catch, and a creator who types 25 on a fibre line should be allowed to find out. The tooltip carries YouTube's number for the tier. `MainViewModel.EffectiveQuality` is the single substitution point, and the encoder options, the step-down policy and the clip buffer all read it — so a rated tier can never stream at the shipped default because one call site was missed. One ordering trap found by the test: the constructor resolves the default tier before the layout store is open, so a read at that point must not cache, or the shipped default shadows the creator's stored rate for the whole run. 670 pass, 0 warnings.
2026-11-12 08:11:13 -08:00
parent 93719a286d
commit f2cab5ca0f
9 changed files with 193 additions and 5 deletions
@@ -0,0 +1,61 @@
+using System;
+using System.IO;
+using System.Linq;
+using Xunit;
+using ytLive.Models;
+using ytLive.ViewModels;
+
+namespace ytLive.Tests;
+
+/// <summary>
+/// The creator's own video rate: per tier, clamped at the tier's YouTube minimum, persisted across
+/// runs, and substituted into every consumer that builds encoder options.
+///
+/// <para>The rule that must never break: whatever the creator typed is what the encoder is asked to
+/// hold, and no tier's minimum is quietly undercut.</para>
+/// </summary>
+[Collection("MainViewModelLayoutPath")]
+public class RatedBitrateTests
+{
+    [Fact]
+    public void The_creator_rate_is_per_tier_clamped_to_the_minimum_and_restored()
+    {
+        var tempDb = Path.Combine(Path.GetTempPath(), $"llamacasty-rate-{Guid.NewGuid():N}.db");
+        MainViewModel.LayoutPathOverride = tempDb;
+        try
+        {
+            var vm = new MainViewModel();
+            var tier60 = vm.QualityOptions.Single(tier => tier.Display == "1080p60");
+            var tier30 = vm.QualityOptions.Single(tier => tier.Display == "1080p30");
+            vm.SelectedQuality = tier60;
+
+            // Unset means the shipped default, not zero.
+            Assert.Equal(tier60.Bitrate, vm.RatedMbps);
+
+            // A creator who knows their line sets their own number, and the encoder sees it.
+            vm.RatedMbps = 15;
+            Assert.Equal(15, vm.RatedMbps);
+            Assert.Equal(15, vm.EffectiveQuality(tier60).Bitrate);
+            Assert.Equal(60, vm.EffectiveQuality(tier60).Fps);   // geometry stays the tier's
+
+            // Below YouTube's minimum for the tier is not a legal target.
+            vm.RatedMbps = 2;
+            Assert.Equal(RateLadder.For(tier60).Minimum, vm.RatedMbps);
+
+            // The other tier keeps its own value — one setting does not leak into the ladder.
+            vm.SelectedQuality = tier30;
+            Assert.Equal(tier30.Bitrate, vm.RatedMbps);
+            vm.SelectedQuality = tier60;
+
+            // And it survives a restart: the same profile, a fresh view model.
+            var reloaded = new MainViewModel();
+            reloaded.SelectedQuality = reloaded.QualityOptions.Single(tier => tier.Display == "1080p60");
+            Assert.Equal(RateLadder.For(tier60).Minimum, reloaded.RatedMbps);
+        }
+        finally
+        {
+            MainViewModel.LayoutPathOverride = null;
+            try { File.Delete(tempDb); } catch (IOException) { }
+        }
+    }
+}