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Craigstreamy HEVC Smart Eng Sub Audio Conform Pack

This pack keeps the same smart_eng_sub + preserve subtitle posture and HEVC strategy as the existing craigstreamy preserve pack, but adds a stricter audio-delivery policy for DTS-family and PCM-family mezzanines.

Intent

This pack standardizes mixed-library inputs into streaming-friendly HEVC outputs while:

  • preserving the smart_eng_sub + preserve subtitle policy
  • preserving AAC and Dolby-family audio streams when they are already acceptable
  • conforming DTS-family and PCM-family audio into open-source Dolby-aligned delivery codecs
  • using MKV whenever subtitle or preserved-audio safety requires it

Subtitle Policy

Canonical subtitle policy for this pack:

  • selection scope: smart_eng_sub
  • handling mode: preserve

This pack uses the same subtitle policy as the existing craigstreamy preserve pack. The shared vocabulary is defined in Subtitle Policy.

What It Optimizes For

  • practical HEVC bitrate reduction across 4K, 1080p SDR, and legacy sub-HD lanes
  • subtitle policy: smart_eng_sub + preserve
  • subtitle-policy-sensitive container branching
  • preserve-first audio policy for already-acceptable streams
  • DTS/PCM delivery cleanup without pretending we can author Atmos
  • loudness normalization only on the audio streams we actually transcode

Audio Conform Plans Of Attack

Source audio shape Plan
DTS or PCM mono / stereo decode -> loudnorm -> AAC
DTS or PCM 3.0 / 4.0 / 5.0 / 5.1 decode -> loudnorm -> E-AC-3 when available, else AC-3
DTS 7.x / DTS:X style high-channel renders or PCM > 5.1 decode/render -> downmix to 5.1 -> loudnorm -> E-AC-3 when available, else AC-3
AAC / AC-3 / E-AC-3 / TrueHD preserve as-is
Preserved stream not suitable for MP4 keep MKV instead of forcing unnecessary audio rewrite

High-Level Assessments

Label Assessment
Dynamic range HDR/DV aware on 4K, SDR-gated on 1080p, broad intake on legacy sub-HD
Resolution 4K / 1080p / legacy sub-HD lane family
Audio codecs AAC + Dolby preserve, DTS/PCM conform
Video codecs HEVC transcode target
Interlacing legacy lane only; optional deinterlace
Volume normalisation applied when DTS/PCM-family audio is transcoded
Crop legacy lane auto-crop enabled
Lowered video bitrate yes
Lowered audio bitrate not as a general policy; only codec-target defaults for DTS/PCM conform
Audio transcoded DTS/PCM-family only
Video transcoded yes
Audio switched DTS/PCM -> AAC / E-AC-3 / AC-3 when needed
Subtitle retained smart_eng_sub + preserve
Subtitle transformed no; preserve mode only
Container changed yes when subtitle or preserved-audio safety requires MKV; otherwise fragmented MP4 with faststart fallback for E-AC-3
Container targets MKV / fragmented MP4
Bitrate targets practical video efficiency; audio preserve-first
Audio bitrate targets codec-target defaults only when DTS/PCM-family audio is conformed
Overall bitrate targets reduce video bitrate while preserving viewing intent and sane audio delivery
Error guardrail skip, missing toolchain, strict DV/HDR mismatch, or unknown error placeholder

Included Profiles

Pack Flow

flowchart LR classDef stage fill:#e0f2fe,stroke:#0284c7,color:#0c4a6e,stroke-width:1.2px; classDef gate fill:#fff7ed,stroke:#f59e0b,color:#7c2d12,stroke-width:1.5px; classDef output fill:#dcfce7,stroke:#16a34a,color:#14532d,stroke-width:1.2px; classDef skip fill:#f3f4f6,stroke:#6b7280,color:#1f2937,stroke-width:1.2px; subgraph Intake["Lane Classification"] A[Candidate media]:::stage --> B{Profile envelope match}:::gate B -->|4K 1920x1080..3840x2160| C[4K lane]:::stage B -->|1080 SDR bt709 1280x720..1920x1080| D[1080p lane]:::stage B -->|Legacy sub-HD 320x240..1279x719| E[Legacy lane]:::stage B -->|No match| X[Routed elsewhere or guardrail-skipped]:::skip end C --> C0[Encode HEVC + preserve HDR/DV intent]:::stage D --> D0[Encode HEVC with SDR guardrails]:::stage E --> E0[Optional deinterlace and stable auto-crop]:::stage E0 --> E1[Encode HEVC legacy lane]:::stage C0 --> C1[Inspect audio streams]:::stage D0 --> D1[Inspect audio streams]:::stage E1 --> E2[Inspect audio streams]:::stage C1 --> C2{DTS/PCM-family stream present?}:::gate D1 --> D2{DTS/PCM-family stream present?}:::gate E2 --> E3{DTS/PCM-family stream present?}:::gate C2 -->|Yes| C3[Conform DTS or PCM to AAC / E-AC-3 / AC-3 + loudnorm]:::stage C2 -->|No| C4[Preserve AAC / Dolby audio]:::stage D2 -->|Yes| D3[Conform DTS or PCM to AAC / E-AC-3 / AC-3 + loudnorm]:::stage D2 -->|No| D4[Preserve AAC / Dolby audio]:::stage E3 -->|Yes| E4[Conform DTS or PCM to AAC / E-AC-3 / AC-3 + loudnorm]:::stage E3 -->|No| E5[Preserve AAC / Dolby audio]:::stage C3 --> Cq{Smart English subtitle or MKV-safe audio required?}:::gate C4 --> Cq D3 --> Dq{Smart English subtitle or MKV-safe audio required?}:::gate D4 --> Dq E4 --> Eq{Smart English subtitle or MKV-safe audio required?}:::gate E5 --> Eq Cq -->|Yes| Cmkv[Emit MKV]:::output Cq -->|No| Cmp4[Emit fragmented MP4 or faststart MP4 for E-AC-3]:::output Dq -->|Yes| Dmkv[Emit MKV]:::output Dq -->|No| Dmp4[Emit fragmented MP4 or faststart MP4 for E-AC-3]:::output Eq -->|Yes| Emkv[Emit MKV]:::output Eq -->|No| Emp4[Emit fragmented MP4 or faststart MP4 for E-AC-3]:::output

What This Pack Does Not Do

  • It does not invent Atmos or proprietary immersive metadata.
  • It does not transcode already-acceptable AAC or Dolby-family streams just to make everything uniform.
  • It does not apply a broad audio bitrate-lowering strategy yet.
  • It does not OCR or convert bitmap subtitles to text subtitles.
  • It does not semantically understand subtitle meaning; subtitle selection uses metadata/flag heuristics.
  • It does not generate ABR ladders (HLS/DASH); outputs are single-file delivery artifacts.
  • It depends on source integrity and toolchain support for DV/HDR retention; strict mode may fail instead of silently downgrading.