{
  "job": {"byte": 1, "type": "i","desc": "Job identification number"},
  "line": {"byte": 5, "type": "i","desc": "Line number"},
  "reel": {"byte": 9, "type": "i","desc": "Reel number"},
  "nt": {"byte": 13, "type": "H","desc": "Number of traces per ensemble"},
  "auxnt": {"byte": 15, "type": "H","desc": "Numer of auxiliary traces per ensemble"},
  "dt": {"byte": 17, "type": "H","desc": "Sample interval"},
  "dtorig": {"byte": 19, "type": "H","desc": "Sample interval of original field recording"},
  "ns": {"byte": 21, "type": "H","desc": "Number of samples per trace"},
  "nsorig": {"byte": 23, "type": "H","desc": "Number of samples per trace for original field recording"},
  "format": {"byte": 25, "type": "H","desc": "Data sample format code"},
  "fold": {"byte": 27, "type": "H","desc": "Ensemble fold"},
  "tsort": {"byte": 29, "type": "h","desc": "Trace sorting code"},
  "vsc": {"byte": 31, "type": "H","desc": "Vertical sum code"},
  "swfs": {"byte": 33, "type": "H","desc": "Sweep frequency at start"},
  "swfe": {"byte": 35, "type": "H","desc": "Sweep frequency at end"},
  "swlen": {"byte": 37, "type": "H","desc": "Sweep length"},
  "swtype": {"byte": 39, "type": "H","desc": "Sweep type code"},
  "swchan": {"byte": 41, "type": "H","desc": "Sweep channel"},
  "swtls": {"byte": 43, "type": "H","desc": "Sweep trace taper length at start"},
  "swtle": {"byte": 45, "type": "H","desc": "Sweep trace taper length at end"},
  "taptype": {"byte": 47, "type": "H","desc": "Taper type"},
  "corr": {"byte": 49, "type": "H","desc": "Correlated data trace"},
  "gain": {"byte": 51, "type": "H","desc": "Binary gain recovered"},
  "amprm": {"byte": 53, "type": "H","desc": "Amplitude recovery method"},
  "msys": {"byte": 55, "type": "H","desc": "Measurement system"},
  "ispol": {"byte": 57, "type": "H","desc": "Impulse signal polarity"},
  "vibpc": {"byte": 59, "type": "H","desc": "Vibrator polarity code"},
  "ent": {"byte": 61, "type": "I","desc": "Extended number of data traces per ensemble"},
  "eauxnt": {"byte": 65, "type": "I","desc": "Extended number of auxiliary traces per ensemble"},
  "ens": {"byte": 69, "type": "I","desc": "Extended number of samples per data trace"},
  "edt": {"byte": 73, "type": "d","desc": "Extended sample interval (IEEE)"},
  "edtorig": {"byte": 81, "type": "d","desc": "Extended sample interval of original field recording (IEEE)"},
  "ensorig": {"byte": 89, "type": "I","desc": "Extended number of samples per trace for original field recording"},
  "efold": {"byte": 93, "type": "I","desc": "Extended ensemble fold"},
  "iconst": {"byte": 97, "type": "I","desc": "The integer constant 16909060_10 (01020304_16)"},
  "unass1": {"byte": 101, "type": "q","desc": "Unassigned1"},
  "unass2": {"byte": 109, "type": "q","desc": "Unassigned2"},
  "unass3": {"byte": 117, "type": "q","desc": "Unassigned3"},
  "unass4": {"byte": 125, "type": "q","desc": "Unassigned4"},
  "unass5": {"byte": 133, "type": "q","desc": "Unassigned5"},
  "unass6": {"byte": 141, "type": "q","desc": "Unassigned6"},
  "unass7": {"byte": 149, "type": "q","desc": "Unassigned7"},
  "unass8": {"byte": 157, "type": "q","desc": "Unassigned8"},
  "unass9": {"byte": 165, "type": "q","desc": "Unassigned9"},
  "unass10": {"byte": 173, "type": "q","desc": "Unassigned10"},
  "unass11": {"byte": 181, "type": "q","desc": "Unassigned11"},
  "unass12": {"byte": 189, "type": "q","desc": "Unassigned12"},
  "unass13": {"byte": 197, "type": "q","desc": "Unassigned13"},
  "unass14": {"byte": 205, "type": "q","desc": "Unassigned14"},
  "unass15": {"byte": 213, "type": "q","desc": "Unassigned15"},
  "unass16": {"byte": 221, "type": "q","desc": "Unassigned16"},
  "unass17": {"byte": 229, "type": "q","desc": "Unassigned17"},
  "unass18": {"byte": 237, "type": "q","desc": "Unassigned18"},
  "unass19": {"byte": 245, "type": "q","desc": "Unassigned19"},
  "unass20": {"byte": 253, "type": "q","desc": "Unassigned20"},
  "unass21": {"byte": 261, "type": "q","desc": "Unassigned21"},
  "unass22": {"byte": 269, "type": "q","desc": "Unassigned22"},
  "unass23": {"byte": 277, "type": "q","desc": "Unassigned23"},
  "unass24": {"byte": 285, "type": "q","desc": "Unassigned24"},
  "unass25": {"byte": 293, "type": "q","desc": "Unassigned25"},
  "segymaj": {"byte": 301, "type": "B","desc": "SEG-Y major format revision number"},
  "segymin": {"byte": 302, "type": "B","desc": "SEG-Y minor format revision number"},
  "fixed": {"byte": 303, "type": "H","desc": "Fixed length trace flag"},
  "ntxthead": {"byte": 305, "type": "h","desc": "Number of 3200-byte extended textual file header records"},
  "maxtrhead": {"byte": 307, "type": "i","desc": "Maximum number of additional 240-byte trace headers"},
  "timbas": {"byte": 311, "type": "h","desc": "Time basis code"},
  "ntfile": {"byte": 313, "type": "Q","desc": "Number of traces in file"},
  "byteoff": {"byte": 321, "type": "Q","desc": "Byte offset of first trace relative to start of file"},
  "ntrailer": {"byte": 329, "type": "i","desc": "Number of 3200-byte data trailer stanza records"},
  "unass26": {"byte": 333, "type": "d","desc": "Unassigned26"},
  "unass27": {"byte": 341, "type": "d","desc": "Unassigned27"},
  "unass28": {"byte": 349, "type": "d","desc": "Unassigned28"},
  "unass29": {"byte": 357, "type": "d","desc": "Unassigned29"},
  "unass30": {"byte": 365, "type": "d","desc": "Unassigned30"},
  "unass31": {"byte": 373, "type": "d","desc": "Unassigned31"},
  "unass32": {"byte": 381, "type": "d","desc": "Unassigned32"},
  "unass33": {"byte": 389, "type": "d","desc": "Unassigned33"},
  "unass34": {"byte": 397, "type": "i","desc": "Unassigned34"}
}
