shanaencoder-x265-lab

name: shanaencoder-x265-lab description: Build and maintain scene-focused x265 CPU presets in a reversible A/B workflow. Use when tuning -crf, -qmin/-qmax, audio mode (copy vs AAC), and goal-oriented preset branches such as size-first, balanced, and detail-first. 用于 场景化 x265 CPU 预设调参：围绕体积、画质、速度做可回滚的分支化维护与 A/B 对比。

Scene X265 Lab / 场景化 x265 调参技能

Purpose / 目标

Create stable, reusable scene preset variants without overwriting proven presets.
不覆盖稳定旧预设，新增可复用的 场景分支方案并支持快速回退。

Workflow / 工作流

1. Pick one baseline preset (for example 24qualityCpuFast.xml).
2. Split by intent: size-first, balanced, detail-first, and same-audio.
3. Keep one variable theme per branch:
   • quality axis: -crf
   • guardrail axis: -qmin/-qmax
   • audio axis: -c:a copy vs -c:a libfdk_aac -b:a 192k
4. Keep filters unchanged unless user explicitly requests changes.
5. Write a short profile note with:
   • source type
   • target resolution
   • quality tier
   • key filters
6. Validate with short clips before batch encoding.

Practical Defaults / 实战默认值

• Balanced scene (1080p): -crf 24 -qmin 17 -qmax 36 -preset fast
• Size-first scene: -crf 26 -qmin 18 -qmax 40 -preset fast
• Detail-first scene: -crf 23 -qmin 16 -qmax 34 -preset fast
• Same-audio branch: prefer -c:a copy when source audio is acceptable

Guardrail Interpretation / 上下限理解

• qmin prevents bitrate spikes caused by over-preserving easy frames.
• qmax avoids severe quality collapse in hard scenes.
• Removing guardrails increases CRF freedom and scene adaptivity, but output size is less predictable.

Safety Rules / 安全规则

• Do not delete or overwrite stable preset files by default.
• Prefer adding a sibling folder for new strategies.
• Keep naming explicit so batch scripts can filter by keywords.

References / 参考

Read scene-x265-cheatsheet.md for quick decision guidance.