BLF Viewer

View and analyze Binary Logging Format (BLF) CAN bus log files directly in VS Code — no external tools required.

BLF is the native recording format of Vector CANalyzer, CANoe, and related automotive diagnostic tools. This extension lets you inspect .blf files as a structured, filterable table without leaving your editor.

Sample Screenshot

Below is a sample viewer screenshot. The left panel shows the message table with filters applied, and the right panel shows the details for a selected CAN frame.

Features

Automatic file association

Opening any .blf file in VS Code launches the viewer automatically. No commands needed.

Virtual scrolling — handles large files

Files with hundreds of thousands of messages open instantly. The viewer renders only the rows currently visible on screen, keeping memory usage constant regardless of file size.

Stats dashboard

At a glance: total message count, recording duration, messages/sec throughput, unique arbitration IDs, active channels, RX/TX split, and CAN FD frame count.

DBC signal decoding

Click the ⊕ DBC button in the toolbar to import a .dbc file. Once loaded:

• A badge shows the file name and the number of matched messages
• Every matched row in the table shows a Name column with the DBC message name
• Selecting a matched row shows a Signals section in the detail panel with each signal's raw hex value, physical value (with unit), and value-table label for enum signals (e.g. Drive, Park)
• Click ✕ next to the badge to unload the DBC and return to raw data

Filter toolbar

Narrow down messages by:

• Arbitration ID — hex substring match, or comma-separated list (e.g. 7E0,7E8) to match multiple IDs at once
• Direction — RX, TX, or both
• Type — Standard CAN, CAN FD, or Error frames
• Channel — individual channel or all

Sortable columns

Click any column header to sort ascending; click again to reverse. Sorting is applied on the full filtered dataset on the extension host before paging, so the order is always correct across all pages.

The table includes both the original relative Time(s) column and a default-visible UTC column with ISO UTC timestamps.

Resizable and reorderable columns

Drag a column edge to resize it. Drag a column header to a new position to reorder. Use the ⊞ Columns button to show or hide individual columns.

Multi-select

• Click — single select
• Ctrl / Cmd + Click — toggle individual rows
• Shift + Click — select a contiguous range

The selection count is shown in the toolbar.

Right-click context menu

Right-click any row for quick actions:

Detail panel

Select any row to see the full message breakdown: byte grid, hex/decimal/binary table for each byte, and all decoded flags (Extended ID, Remote Frame, BRS, ESI).

Supported frame types

• CAN 2.0A — 11-bit standard frames
• CAN 2.0B — 29-bit extended frames
• CAN FD — with Bit Rate Switch (BRS) and Error State Indicator (ESI)
• CAN FD Message 64 payloads — decoded with the CAN FD DLC-to-length mapping so 12/16/20/24/32/48/64-byte payloads display correctly
• Error frames

Theme adaptive

Uses VS Code CSS variables throughout — works correctly with any light or dark color theme.

Requirements

• VS Code 1.109.0 or later
• No external dependencies or native modules — pure TypeScript

Usage

1. Open a .blf file via File → Open File or by double-clicking in the Explorer panel
2. The BLF Viewer opens automatically as a custom editor
3. Use the filter toolbar to search for specific messages
4. Click any row to inspect its bytes in the detail panel on the right
5. Click ⊟ Detail in the top bar to show or hide the detail panel
6. Right-click any row for copy, colorize, filter, and grouping options

You can also open a file explicitly from the Command Palette:

BLF: Open File

Extension Settings

This extension does not contribute any configurable settings.

Release Notes

1.0.1

Fixed CAN_FD_MESSAGE_64 payload parsing for CAN FD BLF files where DATA could be empty or truncated, including correct CAN FD DLC-to-payload-length mapping. Added a UTC timestamp column while preserving the original relative Time(s) column.

1.0.0

DBC import and signal decoding, message name column, multi-ID filter (comma-separated), and a pure-TypeScript DBC parser with Intel/Motorola byte order, signed/unsigned signals, value tables, and comments.

0.2.0

Resizable and reorderable columns, column visibility toggle, real host-side sorting, multi-select, right-click context menu with colorize / group / copy actions, and fixes for sort key mismatch, empty-filter ghost rows, and leading-zero ID matching.

0.1.0

Initial release. Virtual scrolling viewer with filtering, stats dashboard, detail panel, and full CAN / CAN FD / error frame support.

About BLF

The Binary Logging Format (.blf) is a binary container format developed by Vector Informatik GmbH. It stores timestamped CAN, CAN FD, LIN, FlexRay, and other bus messages in compressed blocks (LOBJ containers). This extension implements the CAN and CAN FD portions of the format.

License

MIT