Bilibili Video Evidence

Bilibili Video Evidence

Collect evidence first. Write notes later.

Workflow

1. Parse the BV id and optional p= page index from the user URL.
2. Fetch native subtitles before considering ASR or summaries.
3. If the page exposes no usable subtitle track, or the user explicitly asks for a local/offline subtitle path, switch to the local ASR fallback in references/asr-fallback.md.
4. Write native subtitle artifacts with scripts/bilibili_subtitle_to_md.py, or write ASR fallback artifacts with scripts/bilibili_audio_asr_to_srt.py after the fallback decision is made.
5. Capture direct frame artifacts with scripts/capture_bilibili_screenshot.js when the user wants PNG evidence files.
6. Inspect the repo for an existing screenshot endpoint before adding code.
7. Run scripts/smoke_bilibili_endpoint.js only when the task is specifically about validating a repo-local screenshot route.
8. Report native subtitle access, ASR fallback status, and screenshot access separately.

Outputs

• sectioned.md
• subtitles.json
• audio-16k.wav
• asr.srt
• asr.zh.srt
• asr.json
• frames/*.png
• optional smoke-report.json

Run

Use:

python scripts/bilibili_subtitle_to_md.py \
  --url "https://www.bilibili.com/video/BV1X7411F744?p=5" \
  --output "sectioned.md" \
  --json-output "subtitles.json"

If Bilibili exposes no usable subtitle track, run the local ASR fallback:

python scripts/bilibili_audio_asr_to_srt.py \
  --url "https://www.bilibili.com/video/BV1X7411F744?p=5" \
  --cookie-file "cookie.txt" \
  --output-dir "outputs/P05" \
  --model "small" \
  --device "cpu" \
  --compute-type "int8"

When a Chinese subtitle translation is requested after ASR, keep the .srt numbering and timestamps unchanged, translate only the subtitle text, and preserve technical keywords in English. Read references/asr-fallback.md for the exact fallback rules and prompt pattern.

Capture a frame directly:

node scripts/capture_bilibili_screenshot.js \
  "https://www.bilibili.com/video/BV15DG7zxENa/" \
  00:24 \
  --output=frames/intro.png

Validate a repo-local screenshot endpoint:

node scripts/smoke_bilibili_endpoint.js <repo-root> <bilibili-url> --timestamps=00:13,10:25

Cookie Handling

• Prefer the full browser Cookie header over SESSDATA alone.
• Accept either --cookie or --cookie-file.
• If neither is passed, the subtitle script may fall back to BILIBILI_COOKIE or BILIBILI_SESSION_TOKEN from the environment.
• Strip a leading Cookie: prefix if the user pasted a raw header line.
• Try x/player/v2 first and keep x/player/wbi/v2 as a fallback source.
• The local ASR fallback may still need browser cookie state to resolve or fetch the media stream.
• If login-gated subtitle access still fails, ask for a fresh full Cookie header or Copy as cURL.
• Treat frame capture success and subtitle access as separate checks.

Subtitle Artifacts

The subtitle script writes Markdown with:

• video title
• source URL
• BV id and CID
• page index and page title
• subtitle language and subtitle URL
• subtitle count
• timeline sections grouped by fixed-length buckets

If --output is omitted, the default Markdown filename is the sanitized video title.

Each section looks like:

### 05:00 - 05:59

- `05:03` Subtitle text
- `05:07` Another subtitle line

Frame Artifacts

• Default direct-capture output goes under frames/.
• Prefer one representative PNG per requested timestamp.
• Read references/implementation.md for the compact rules.
• Read references/keyframe-reference.md when you need the detailed rationale behind HTML parsing, stream selection, timestamp handling, or ffmpeg flags.
• Read references/asr-fallback.md when native subtitles are missing or when the user explicitly requests local ASR output.

Endpoint Smoke

When the user wants screenshot endpoint validation instead of standalone PNG capture:

1. Search the repo for ffmpeg, __playinfo__, /api/bilibili/screenshot, ffmpeg-static, and captureBilibiliScreenshot.
2. Prefer reusing an existing server-side screenshot endpoint over adding a new one.
3. Run the smoke script against the repo root and video URL.
4. Treat a 200 image/jpeg response for two timestamps as the minimum passing smoke test. The smoke script should fail if a response is empty or does not look like a JPEG.

If the target repo already has scripts/smoke-bilibili.js, reuse it instead of duplicating logic.

Validation

Before finishing:

1. Confirm the page title and page number match the requested URL.
2. Confirm the subtitle list is non-empty when native subtitle output was requested.
3. Confirm timestamps increase monotonically in the first few lines of sectioned.md.
4. Confirm the Markdown file exists on disk.
5. If subtitles.json was requested, confirm it exists and includes API-source metadata plus merged groups.
6. If ASR fallback was requested, confirm audio-16k.wav, asr.srt, and asr.json exist on disk.
7. If Chinese translation was requested after ASR, confirm asr.zh.srt exists and keeps the original timestamps.
8. If PNG frames were requested, confirm the files exist under frames/ or the requested output path.
9. If smoke testing was requested, confirm the endpoint returns non-empty JPEGs and records smoke-report.json.
10. If native subtitle access, ASR fallback, and screenshot checks differ, report them separately instead of collapsing them into one status.

Failure Handling

• If no BV id can be parsed, fail clearly.
• If the requested p= is out of range, fail clearly.
• If the subtitle track is missing, say the page currently exposes no subtitle track and then switch to the local ASR fallback when the task still requires subtitles.
• If login-gated subtitles still fail with a full cookie, ask for a fresh cookie or copied cURL request.
• If direct frame capture works but subtitle access fails, report them separately instead of collapsing them into one failure.
• If the screenshot endpoint works but subtitle access fails, report them separately instead of collapsing them into one failure.
• Do not claim that native subtitles were fetched when you actually switched to ASR.
• Do not claim that ASR was used unless you actually switched to ASR.