Preallocated headers (near-empty corrupt files) #
|Problem ID||Manufacturer||Affected Firmware||Affected Hardware||Status|
|FL001||Frontier Labs||unknown: at least most versions of v3.0+||BAR||Minor problem|
Often when a sensor is interrupted - through a fault, lack of space, or a power failure, fragments of files produced and left in the file system.
These fragments are often:
- Occurs for both WAVE and FLAC files
- small but not empty; usually around 153 bytes for FLAC files and 44 bytes for WAVE files
- contain a
WAVEheader, even if the recording format is FLAC
- and often contain incoherent or misplaced data
for example: a FLAC comment could be in the
datasection of a
Or fragments of a header that are mostly null bytes but still have some data in them
There is no usable information in these files and they cannot be reliably repaired.
Since these files are regularly produced, and for we suspect a variety of reasons this issue may be reflective of several smaller issues.
Minor problem: most tools fail to process these files, they are mainly an annoyance, especially since at a surface level they look like small but valid files.
Status with vendor #
It was suggested to FL they should attempt to clean up or delete such files, but this was a long time ago. No recent contact about this issue has been attempted.
Effects of the problem on common tools #
Emu has support for detecting this problem and renaming problem files: https://github.com/QutEcoacoustics/emu/blob/master/docs/fixes.md#rename-stub-files-fix-fl001
Acoustic Workbench (Ecosounds, A2O) #
Currently fail - ungracefully - to harvest files
Will generally produce a variety of errors such as:
[pcm_s16le @ 0x5575904db580] PCM channels out of bounds Last message repeated 1 times [wav @ 0x5575904d9ac0] Failed to open codec in avformat_find_stream_info [wav @ 0x5575904d9ac0] Estimating duration from bitrate, this may be inaccurate [wav @ 0x5575904d9ac0] Could not find codec parameters for stream 0 (Audio: pcm_s16le ( / 0x0001), 11264 Hz, 0 channels): unspecified number of channels Consider increasing the value for the 'analyzeduration' and 'probesize' options Input #0, wav, from '/data/harvester_to_do/harvest_28/sdfsdf/20211129_79/314/785/20200711_STUDY/20200711T033015+0000_REC.flac': Duration: 00:00:00.00, bitrate: 492 kb/s Stream #0:0: Audio: pcm_s16le ( / 0x0001), 11264 Hz, 0 channels [pcm_s16le @ 0x5575904de800] PCM channels out of bounds Could not open codec for input stream 0
The metadata command will also report roughly correct values (0 duration, 0 samples) for these files.