print(f"Successfully loaded. Channels found: len(mdf_obj.channels)") # Saving as MF4 with compression level 2 (balanced) mdf_obj.save(output_path, compression=2, overwrite=True) print(f"Conversion complete: output_path") except Exception as e: print(f"Error: e") sys.exit(1) if == " main ": if len(sys.argv) != 3: print("Usage: python convert_blf.py input.blf output.mf4") sys.exit(1)

Get-ChildItem -Filter *.blf | ForEach-Object $output = $_.BaseName + ".mf4" Write-Host "Converting $($_.Name) to $output" python -c "from asammdf import MDF; MDF('$($_.FullName)').save('$output', compression=2)"

mdf = MDF(input_path, sync_timestamps=True) Error: MF4 output is 10x larger than the BLF input. Cause: Default MF4 saves XML data uncompressed. Fix: Use compression=2 (Deflate) or compression=3 (LZ4) when saving:

mdf.save(output_path, compression=3) # LZ4 is fastest The "new" trend is data lake automation. Here is a bash script to convert an entire folder:

pip install --upgrade asammdf Note: For large files, install the optional LZMA compression library: pip install lz4 brotli Create a file called convert_blf.py :

from asammdf import MDF mdf = MDF("my_vehicle_log.mf4") print(mdf) # Displays metadata, channel count, and duration Even with modern tools, BLF to MF4 conversion can hit snags. Here are the latest fixes for 2025. Problem 1: "Unsupported Bus Type" Error: ValueError: Unknown bus type 5 Cause: The BLF contains FlexRay or Ethernet data that asammdf cannot parse natively. Solution: Use Vector’s blf2mdf.exe or filter the BLF to only CAN channels using Vector CANalyzer’s conversion matrix. Problem 2: Timestamp Overflow (The 48-hour bug) Error: Timestamps appear as negative numbers or wrap around. Cause: Old BLF files use 32-bit microsecond timestamps that overflow. New fix: In asammdf , force 64-bit conversion:

Do not store your converted MF4 files on spinning hard drives. Use NVMe SSDs for the conversion process, as BLF and MF4 are I/O-intensive formats. Once converted, consider compressing the MF4 using asammdf 's compress(Object) method to save 40-60% disk space. Have you encountered a specific error while trying to convert BLF to MF4? Drop a comment below or check the GitHub issues page for asammdf – the maintainers typically respond within 48 hours.