gramps
f2cab5ca0f
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.
90 lines
3.8 KiB
C#
90 lines
3.8 KiB
C#
using ytLive.Models;
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namespace ytLive.ViewModels;
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/// <summary>
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/// The creator's own video rate, per tier — the latitude the tier table deliberately does not take
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/// away. A creator who knows their upload can set any rate from the tier's YouTube minimum upward;
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/// nothing here invents a ceiling, because a wrong guess is what live step-down exists to catch.
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///
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/// <para><b>Why per tier:</b> a number that is sensible at 1080p60 is wasteful at 720p30, and the
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/// creator who tuned one tier has not tuned the other. Unset means "use the shipped default", which
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/// is what <see cref="EffectiveQuality"/> substitutes.</para>
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///
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/// <para><b>Why this matters now:</b> with CBR holding the target (<c>FfmpegArgs.AddRateControl</c>)
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/// the number the creator types is the number that goes out, so it is a real quality choice rather
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/// than an average to undershoot.</para>
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/// </summary>
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public partial class MainViewModel
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{
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private readonly Dictionary<string, double> _ratedMbpsByTier = new(StringComparer.Ordinal);
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/// <summary>The tier with the creator's rate substituted for the shipped default. Every consumer
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/// that builds encoder options or a step-down policy must use this, never the raw tier.</summary>
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public QualityOption EffectiveQuality(QualityOption tier)
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=> RatedFor(tier) is var rated && Math.Abs(rated - tier.Bitrate) > 0.001
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? tier with { Bitrate = rated }
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: tier;
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private double RatedFor(QualityOption tier)
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{
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if (_ratedMbpsByTier.TryGetValue(tier.Display, out var cached)) return cached;
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// The constructor resolves the default tier before the layout store exists, so the first read
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// must not cache: a cached default would shadow the creator's stored rate for that run.
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var stored = _layoutStore is null ? null : _layoutStore.LoadRatedMbps(tier.Display);
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var value = Math.Max(stored ?? tier.Bitrate, RateLadder.For(tier).Minimum);
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if (_layoutStore is not null) _ratedMbpsByTier[tier.Display] = value;
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return value;
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}
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/// <summary>The rate the selected tier will stream at, in Mbps.</summary>
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public double RatedMbps
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{
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get => RatedFor(SelectedQuality);
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set
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{
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var tier = SelectedQuality;
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var band = RateLadder.For(tier);
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// Below the tier minimum YouTube will not hold the resolution; above ~100 is not a stream.
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var clamped = Math.Clamp(Math.Round(value, 1), band.Minimum, 100.0);
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if (Math.Abs(clamped - RatedFor(tier)) < 0.05)
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{
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OnPropertyChanged(nameof(RatedMbps));
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return;
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}
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_ratedMbpsByTier[tier.Display] = clamped;
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_layoutStore.SaveRatedMbps(tier.Display, clamped);
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ApplyStreamQuality(tier);
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OnPropertyChanged(nameof(RatedMbps));
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OnPropertyChanged(nameof(RateHint));
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}
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}
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/// <summary>What YouTube expects for this tier, shown next to the field.</summary>
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public string RateHint
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{
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get
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{
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var band = RateLadder.For(SelectedQuality);
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return $"YouTube recommends {band.Recommended:0.#} Mbps for {SelectedQuality.Display}; " +
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$"it will not take less than {band.Minimum:0.#}. Your connection must carry this " +
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"plus ~20% headroom.";
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}
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}
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/// <summary>Restores the shipped default for the selected tier.</summary>
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public void ResetRatedMbps()
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{
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var tier = SelectedQuality;
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if (!_ratedMbpsByTier.ContainsKey(tier.Display)) return;
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_ratedMbpsByTier.Remove(tier.Display);
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_layoutStore.SaveRatedMbps(tier.Display, null);
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_ratedMbpsByTier[tier.Display] = RatedFor(tier);
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ApplyStreamQuality(tier);
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OnPropertyChanged(nameof(RatedMbps));
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OnPropertyChanged(nameof(RateHint));
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}
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}
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