Generating incorrect durations for FLAC files #
|Problem ID||Manufacturer||Affected Firmware||Affected Hardware||Status|
|FL010||Frontier Labs||3.17 to 3.24, 3.30||BAR||Major problem|
It appears that Frontier Labs writes an incorrect value for the
in the FLAC headers.
For this specific problem the duration in the FLAC header is always set to twice (2×) the duration of actual audio in the file.
This affects firmwares 3.17 to 3.24.
Most audio processing tools will fail eventually when they pass the point where valid data exists.
Status with vendor #
FL is aware of the issue and fixed it in version 3.24 after being notified by us.
We recently encountered an example files that had the same issue in firmware 3.30.
Effects of the problem on common tools #
EMU can fix the duration of files in batch
Audacity opens as much of the file as is available
Converting the file from FLAC to WAVE via sox will not fail and output as much data as is available. Becareful though: this process strips metadata from the file. We recommend fixing the files with EMU.
Acoustics Workbench (Ecosounds, A2O) #
The workbench uses EMU to repair the files on ingestion.
Doesn’t work but it can be worked around by analyzing the first half of the file by specifying the
-s 0 -e <actual end offset> arguments.
If EMU is used files can be repaired before processing and now workarounds are needed.