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Craigstreamy HEVC Smart English Subtitle Convert 4K Profile

Generated from stock preset pack craigstreamy-hevc-smart-eng-sub-subtitle-convert.

Dependencies

Tool Needed Why
ffmpeg required scenario execution, encode/transcode, and mux packaging
ffprobe required criteria probing and stream/metadata inspection

E2E Verification

This profile is considered e2e-verified when its mapped suites pass in CI.

Suite What it proves Toolchain version report
tests/e2e/run_profile_actions_e2e.sh action-level output behavior, guardrails, and subtitle-intent pathways tests/e2e/.reports/latest/run_profile_actions_e2e_toolchain_versions.md

Intent

This profile converts candidates into streaming-friendly HEVC outputs while keeping the smart_eng_sub subtitle selection heuristic and converting selected text subtitles into delivery-friendly text form when the final container remains MP4-friendly.

What It Optimizes For

  • practical bitrate efficiency with a consistent HEVC target
  • preserve all audio streams by default when packaging permits
  • subtitle policy: smart_eng_sub + subtitle_convert
  • conditional container selection: stream-ready MP4 when selected subtitles are text-convertible, explicit fallback for bitmap subtitles

Input Envelope

Field Value
Codec any
Bit depth any
Color space any
Min resolution 1920x1080
Max resolution 3840x2160

Scenario Map

Scenario Command
RES_JUST_RIGHT transcode_hevc_4k_smart_eng_sub_subtitle_convert_profile.sh
ELSE profile_guardrail_skip.sh (requires 1920x1080 to 3840x2160 input)

Runtime Behavior

  • Scenario RES_JUST_RIGHT uses action script transcode_hevc_4k_smart_eng_sub_subtitle_convert_profile.sh.
  • Scenario ELSE uses action script profile_guardrail_skip.sh.

Action summary from transcode_hevc_4k_smart_eng_sub_subtitle_convert_profile.sh:

  • delegates to the canonical 4K HEVC subtitle-aware action
  • keeps selection scope at smart_eng_sub
  • changes subtitle mode to subtitle_convert
  • preserves audio streams with stream copy
  • fails on bitmap subtitle conversion unless VFO_SUBTITLE_CONVERT_BITMAP_POLICY=preserve_mkv

Starting Inputs And Expected Outputs

Aspect What this profile expects / does
Starting containers mkv, mp4, mov, mxf (anything ffmpeg can demux)
Required codec envelope any / any-bit / any
Required resolution range 1920x1080 to 3840x2160
If criteria do not match candidate is routed to another profile or skipped
If criteria match scenario order is evaluated and first match executes
Output intent conditional: stream-ready MP4 with converted text subtitles when the smart_eng_sub policy selects text subtitles; fallback behavior is controlled by VFO_SUBTITLE_CONVERT_BITMAP_POLICY

Flow

flowchart LR classDef gate fill:#fff7ed,stroke:#f59e0b,color:#7c2d12,stroke-width:1.5px; classDef stage fill:#e0f2fe,stroke:#0284c7,color:#0c4a6e,stroke-width:1.2px; classDef output fill:#dcfce7,stroke:#16a34a,color:#14532d,stroke-width:1.2px; classDef skip fill:#f3f4f6,stroke:#6b7280,color:#1f2937,stroke-width:1.2px; A[Input candidate: mkv / mp4 / mov / mxf]:::stage --> B[Probe codec bits color resolution]:::stage B --> C{Matches profile criteria envelope?}:::gate C -->|No| Z[Handled by other profile or guardrail skipped]:::skip C -->|Yes| D{Evaluate scenarios in order}:::gate D --> E[Execute subtitle-policy action]:::stage E --> P[Optional lane-specific pre-processing]:::stage P --> F{Selected subtitle is text-convertible and MP4 remains viable?}:::gate F -->|Yes| G[Encode HEVC + preserve audio + convert selected subtitle to mov_text]:::stage G --> H[Emit MP4 output with converted subtitle text]:::output F -->|No| I[Encode HEVC + preserve audio + apply bitmap or fallback subtitle policy]:::stage I --> J[Emit explicit fallback output (usually MKV preserve or fail)]:::stage J --> K[Emit final profile artifact]:::output

What This Profile Does Not Do

  • It does not normalize frame rate; source cadence/timebase is preserved by default.
  • It does not transcode audio for target-device compatibility by default.
  • It does not guarantee every input audio codec is valid for every selected output container.
  • It does not semantically understand subtitle meaning; subtitle selection is metadata and flag driven.
  • It does not OCR or convert bitmap subtitles to text subtitles.
  • It does not generate ABR ladders (HLS/DASH); output is a single-file artifact.
  • It does not certify playback on every device model; profile criteria are compatibility-oriented guardrails.
  • It does not enforce PSNR/SSIM/VMAF thresholds unless quality checks are explicitly enabled and configured.
  • It does not invent missing HDR/DV essence; metadata repair is heuristic and can be disabled.
  • It depends on source integrity and toolchain support for DV/HDR retention; strict mode may fail instead of silently downgrading.

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 preserved by default
Video codecs HEVC transcode target
Interlacing legacy lane only; optional deinterlace
Volume normalisation not applied by default
Crop legacy lane auto-crop enabled
Lowered video bitrate yes
Lowered audio bitrate no by default
Audio transcoded no by default
Video transcoded yes
Audio switched no; stream copy preferred
Subtitle retained smart_eng_sub + subtitle_convert
Subtitle transformed selected text subtitles -> mov_text
Container changed yes when subtitle conversion succeeds into MP4 text form; bitmap conversion follows explicit fallback policy
Container targets MKV / fragmented MP4
Bitrate targets practical efficiency with delivery-friendly subtitle text outputs
Audio bitrate targets copy/preserve unless a future audio profile says otherwise
Overall bitrate targets reduce video bitrate while maintaining viewing intent and subtitle compatibility
Error guardrail skip, missing toolchain, strict DV/HDR mismatch, or unknown error placeholder

Source

  • Preset file: services/vfo/presets/craigstreamy-hevc-smart-eng-sub-subtitle-convert/vfo_config.preset.conf
  • Generated by: infra/scripts/generate-profile-docs.sh