FL001 Preallocated headers
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
RIFFandWAVEheader, 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 aWAVEstruct
-
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.
Status #
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 #
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
ffmpeg/ffprobe #
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 ([1][0][0][0] / 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 ([1][0][0][0] / 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.