Vital File Format #522
Teunis (2022-10-18 08:32)
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· 1 comment(s)
In the description of the "TRKINFO" (Structure for track information) on page 6, there's specified "recfmt".
I assume the storage space width expressed in bytes is the following:
FMT_FLOAT 4 bytes
FMT_DOUBLE 8 bytes
FMT_CHAR 1 byte
FMT_BYTE 1 byte
FMT_SHORT 2 bytes
FMT_WORD 2 bytes
FMT_LONG 4 bytes
FMT_DWORD 4 bytes
Is my assumption correct?
Second question, all these formats are "signed" and use 2nd complement?
Also, FMT_FLOAT and FMT_DOUBLE are specified according to IEEE 754? https://en.wikipedia.org/wiki/IEEE_754-1985" target="_blank">https://en.wikipedia.org/wiki/IEEE_754-1985
Thanks.
TvB
vitaldb2017 (2022-11-29 04:27)
Sorry for the late response.
For the first question, your assumption is correct.
For the second question, FMT_FLOAT and FMT_DOUBLE follow the IEEE-754, but FMT_BYTE, FMT_WORD, and FMT_DWORD are unsigned, while other types are signed.
You can use the open-source implementations for reading the vital file format in Python, Javascript and C/C++.
https://github.com/vitaldb/vitalutils/blob/master/python/vitaldb-pypi/vitaldb/utils.py
https://github.com/vitaldb/vitalutils/blob/master/Javascript/vitaldb.js
https://github.com/vitaldb/vitalutils/blob/master/C%2B%2B/vital_recs.cpp
For the first question, your assumption is correct.
For the second question, FMT_FLOAT and FMT_DOUBLE follow the IEEE-754, but FMT_BYTE, FMT_WORD, and FMT_DWORD are unsigned, while other types are signed.
You can use the open-source implementations for reading the vital file format in Python, Javascript and C/C++.
https://github.com/vitaldb/vitalutils/blob/master/python/vitaldb-pypi/vitaldb/utils.py
https://github.com/vitaldb/vitalutils/blob/master/Javascript/vitaldb.js
https://github.com/vitaldb/vitalutils/blob/master/C%2B%2B/vital_recs.cpp