Roadmap M2: Dahua adapter #5

New issue

Closed

opened 2026-05-27 19:37:07 +00:00 by coding-agent-marvin8 · 1 comment

coding-agent-marvin8 commented 2026-05-27 19:37:07 +00:00 (Migrated from codeberg.org)

Copy link

Cang needs to understand the folder structure written by Dahua NVRs so it can locate video clips and their associated snapshot images.

Dahua NVRs organise recordings under a root directory with the camera serial as the top-level folder, then date, channel, and hour sub-directories. Video clips are .dav files; each clip has a matching set of per-second JPEG snapshots stored in a parallel jpg/ tree. Clips that recorded a motion event carry an [M] flag in the filename; the first frame of a recording sequence carries [F].

This milestone delivers the adapter layer that turns that raw folder tree into structured IncomingClip objects that the rest of the pipeline can consume, without needing to know any Dahua-specific details.

Cang needs to understand the folder structure written by Dahua NVRs so it can locate video clips and their associated snapshot images. Dahua NVRs organise recordings under a root directory with the camera serial as the top-level folder, then date, channel, and hour sub-directories. Video clips are `.dav` files; each clip has a matching set of per-second JPEG snapshots stored in a parallel `jpg/` tree. Clips that recorded a motion event carry an `[M]` flag in the filename; the first frame of a recording sequence carries `[F]`. This milestone delivers the adapter layer that turns that raw folder tree into structured `IncomingClip` objects that the rest of the pipeline can consume, without needing to know any Dahua-specific details.

coding-agent-marvin8 commented 2026-05-27 19:47:56 +00:00 (Migrated from codeberg.org)

Copy link

Findings

Explored the real NVR folder tree from dahua-folders-files.txt:

• Root: <serial>/<YYYY-MM-DD>/<channel>/dav/<HH>/<stem>.dav
• Snapshot tree: <serial>/<YYYY-MM-DD>/<channel>/jpg/<HH>/<MM>/<SS>[flags].jpg
• Clip stem format: HH.MM.SS-HH.MM.SS[flags][0@0][0]
  • [M] = motion event, [F] = first frame of recording sequence
  • [0@0][0] suffix is always present but carries no useful information
• .idx sidecar files exist for every .dav — skip/ignore them
• Snapshot times are derived from the directory path + filename (HH from dir, MM from dir, SS from stem prefix)
• Snapshots are matched to a clip by timestamp range (clip.start <= snapshot_time <= clip.end), not by filename stem

Plan of attack

1. src/cang/adapters/base.py — IncomingClip dataclass (path, serial, date, channel, start, end, motion, first_frame, snapshots) + BaseAdapter ABC with scan(root) -> Iterator[IncomingClip]
2. tests/adapters/test_dahua.py — failing tests first (TDD):
   • Unit: _parse_clip_stem, _parse_snapshot_path, boundary inclusion/exclusion
   • Integration: minimal tmp_path tree, assert 2 clips yielded with correct snapshot lists
3. src/cang/adapters/dahua.py — DahuaAdapter.scan() walks the tree, parses filenames with regex, matches snapshots per the timestamp range logic; skips .idx files

Branch: feat/issue-5-m2-dahua-adapter

## Findings Explored the real NVR folder tree from `dahua-folders-files.txt`: - Root: `<serial>/<YYYY-MM-DD>/<channel>/dav/<HH>/<stem>.dav` - Snapshot tree: `<serial>/<YYYY-MM-DD>/<channel>/jpg/<HH>/<MM>/<SS>[flags].jpg` - Clip stem format: `HH.MM.SS-HH.MM.SS[flags][0@0][0]` - `[M]` = motion event, `[F]` = first frame of recording sequence - `[0@0][0]` suffix is always present but carries no useful information - `.idx` sidecar files exist for every `.dav` — skip/ignore them - Snapshot times are derived from the directory path + filename (HH from dir, MM from dir, SS from stem prefix) - Snapshots are matched to a clip by timestamp range (`clip.start <= snapshot_time <= clip.end`), not by filename stem ## Plan of attack 1. `src/cang/adapters/base.py` — `IncomingClip` dataclass (path, serial, date, channel, start, end, motion, first_frame, snapshots) + `BaseAdapter` ABC with `scan(root) -> Iterator[IncomingClip]` 2. `tests/adapters/test_dahua.py` — failing tests first (TDD): - Unit: `_parse_clip_stem`, `_parse_snapshot_path`, boundary inclusion/exclusion - Integration: minimal `tmp_path` tree, assert 2 clips yielded with correct snapshot lists 3. `src/cang/adapters/dahua.py` — `DahuaAdapter.scan()` walks the tree, parses filenames with regex, matches snapshots per the timestamp range logic; skips `.idx` files Branch: `feat/issue-5-m2-dahua-adapter`

Sign in to join this conversation.

No Branch/Tag specified

Branches Tags

main

pages

2026.8.4

2026.7.25

2026.7.24

2026.7.23

2026.7.22

0.10.1

0.10.0

0.9.0

0.8.0

0.7.0

0.6.0

0.5.0

0.4.2

0.4.1

0.4.0

0.3.12

0.3.11

0.3.10

0.3.9

0.3.8

0.3.7

0.3.6

0.3.5

0.3.4

0.3.3

0.3.2

0.3.1

0.3.0

0.2.0

Labels

Clear labels

No items

No labels

Milestone

Clear milestone

No items

No milestone

Assignees

Clear assignees

No assignees

1 participant

Notifications

Subscribe

Due date

The due date is invalid or out of range. Please use the format "yyyy-mm-dd".

No due date set.

Dependencies

No dependencies set

Reference

marvin8/cang#5

No description provided.