Comments and danmaku

bilibili has two kinds of conversation: threaded comments under an object, and danmaku, the bullet-chat that scrolls across a video. bili reads both as clean structured records.

Comments

bili comments BV17x411w7KC

comments walks the full comment tree: top-level comments and the replies nested under each one. It works on anything that can be commented on, not just videos, and figures out the object type from the id you give it:

bili comments BV17x411w7KC      # a video
bili comments cv7018872         # a column article
bili comments au1               # an audio track
bili comments <dynamic-id>      # a dynamic post

Each record carries the author, the text, the like count, the timestamp, and the reply relationship, so you can reconstruct threads downstream:

bili comments BVID -o jsonl > comments.jsonl

Use -n to cap how many you pull on a busy video, and --order where the endpoint supports sorting by time or by likes.

Danmaku

bili danmaku BV17x411w7KC

Danmaku is delivered as protobuf segments, one per six minutes of video. bili fetches the segments for a part and decodes them into rows with progress (the millisecond offset into the video), mode, color, fontsize, content, and the sender's hashed id.

Because it is plain data, it answers questions a player cannot:

# the busiest moments, by comment count per 10s bucket
bili danmaku BVID -o jsonl \
  | jq -r '(.progress/10000|floor) ' | sort -n | uniq -c | sort -rn | head

# every comment in the first minute
bili danmaku BVID -o jsonl | jq -r 'select(.progress < 60000) | .content'

For a multi-part video, --page selects the part (see videos).

Pulling both at scale

When you want the whole conversation around a set of videos, let crawl do it:

bili crawl BVID --out ./data --comments --danmaku
# writes comments.jsonl and danmaku.jsonl alongside videos.jsonl