SRT

SRT

Subtitles are translated block by block. Each block keeps its number and its timeline.

How the file is read

• The file is split into blocks at blank lines. A block is a number, a timeline and one or more lines of text.
• By default each block is its own request. --accumulated_num N puts consecutive blocks into one request, up to N characters (capped at 512).
• The loader's own prompt tells the model to leave each block's number and timeline alone. If you replace the user template with --prompt, say that in your template too, or the answer will not parse as SRT. The run warns about this.

What you get

• <name>_bilingual.srt beside the input. Each block keeps its number and timeline, with the original text followed by the translation. With --single_translate, the translation only.
• On Ctrl+C or an error: <name>_bilingual_temp.srt and a checkpoint. Rerun with --resume.

Recommended command

bbook_maker \
  --book_name test_books/Lex_Fridman_episode_322.srt \
  --language zh-hans \
  --accumulated_num 400

Flags that apply

Route and run

These work the same on every format.

flag	what it does
--book_name PATH	The file to translate. The extension picks the format.
-m, --model MODEL	The model id, exactly as the endpoint names it. Default gpt-6-luna on the openai format.
--key KEY	API key; several comma-separated keys rotate. Falls back to BBM_API_KEY, then the format's own variable.
--api_base URL	The endpoint. Defaults to the format's official host.
--api_format FORMAT	The API the endpoint speaks, or a translation service. Inferred from --api_base when left out.
--provider NAME	A named endpoint from bbm_providers.json.
--model_list IDS	Several models to rotate across. Refused with --use_context session.
--language LANGUAGE	Target language: a tag, a name, or TAG:NAME. Default zh-hans.
--source_lang LANGUAGE	Source language, stated. Reaches every LLM prompt; sent as a field on qwen and customapi.
--prompt VALUE_OR_FILE	Custom prompt: user template (must contain {text}), system, style.
--temperature FLOAT	Sampling temperature, on the formats that take one.
--no-thinking	Ask the model not to reason before answering. The field is negotiated on the OpenAI-shaped routes; thinking: disabled on anthropic; refused on codex.
--extra_body JSON	Extra request-body fields on the openai and anthropic routes.
--extra_headers JSON	Extra HTTP headers on the openai and anthropic routes.
--interval SECONDS	Pause between requests. Only the gemini format uses it.
-p, --proxy URL	HTTP proxy for the run.
--test	Translate only the first paragraphs.
--test_num N	How many, with --test (default 10).
--resume	Continue an interrupted run from its checkpoint.
--single_translate	Write the translation only, without the original.

SRT flags

flag	what it does
--accumulated_num N	Characters of subtitle blocks sent in one request (capped at 512 for SRT).

Not for this format

• --batch_size: not read by the SRT loader; group with --accumulated_num.
• --use_context: the SRT loader never hands context to the model, in either mode; the run warns.
• --context_paragraph_limit, --context-compact-at, --no-context-compact: context flags; nothing reads them here.
• --glossary, --glossary-auto: forwarded by the EPUB, Markdown and PDF loaders only; the run warns.
• --max-batch-units, --plan-classify, --plan-dry-run, --plan-min-coverage, --poetry-group-size: plan mode is EPUB only.
• --classify-model, --classify-base-url, --classify-key (and --plan-classify-model, the old name): nothing classifies on this format yet. The run warns that the flag is ignored.
• --translate-tags, --exclude-translate-tags, --allow_navigable_strings: EPUB markup selectors; the run warns.
• --only_filelist, --exclude_filelist: EPUB internal files; ignored.
• --block_size, --sentence_mode: EPUB only; ignored.
• --parallel-workers: the SRT run stays serial; the run warns.
• --translation_style, --translation_color: subtitles carry no style; the run warns.
• --no_disclosure, --translation-metadata: the output carries no credit line and no metadata file; the run warns.
• --retranslate: EPUB only; refused.
• --quiet: EPUB only; the run warns.
• --batch, --batch-use: the SRT loader does not implement the Batch API.
• --to-epub, --pdf-ocr, --ocr-replace-layer, --device, --ocr-lang, --pages, --no-formula-images, --pdf_layout, --img-model, --img-base-url, --img-key: PDF only. --to-epub on this format stops the run; the others warn or do nothing (the three image flags: the run warns that only the PDF route has an image step).