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FFID Fix corrects wrap-around or reset problems in the FFID (First File Identification) trace header field that arise when seismic data is recorded across multiple tape reels. On each new reel, recording equipment typically restarts the FFID counter from a low value, causing the same FFID numbers to appear more than once in the combined dataset. This ambiguity prevents geometry assignment software from uniquely identifying shot records.
The module automatically detects reel boundaries by scanning the trace header geometry for FFID values that repeat (i.e., the sequence resets). At each detected boundary it adds a cumulative offset taken from the user-supplied reel offset table, making the FFID sequence globally unique across all reels. Two modes are available: FFID mode rewrites the FFID header values in the output geometry, while Source line mode leaves FFID values unchanged and only rebuilds the source/receiver associations using the corrected reel assignment.
Note: This module is deprecated. It operates on trace header geometry items (not seismic amplitude data) and is intended for legacy tape-based acquisition datasets where the standard SEG-Y FFID field wraps around across reel boundaries.
Connect the input trace geometry item here. This is the trace header collection describing shot records across all reels, where FFID values may repeat at reel boundaries. The module reads the FFID field from each trace header entry to detect where reel resets occur.
The sorted trace header index (GTraceVectorItem) corresponding to the input geometry. This provides the ordered list of all trace headers that will be scanned for FFID reset boundaries. The headers must be sorted in acquisition order (by FFID) so that reel transitions are detected correctly.
Selects how the reel boundary correction is applied to the output geometry. Two options are available:
FFID (default) — The FFID header value of every trace is incremented by the cumulative reel offset for its reel. After processing, each shot record has a unique FFID across the entire dataset. Use this option when downstream geometry assignment software relies on the FFID field to identify shot records.
Source line — The FFID header values are left unchanged. Only the source/receiver geometry associations are rebuilt using the reel offset information to resolve ambiguities. Use this option when the FFID values themselves must remain as originally recorded, but the internal geometry links need to be corrected.
A table of integer offsets, one entry per reel boundary. Each entry specifies the FFID offset to add when the module detects that the FFID sequence has reset and crossed into a new reel. The first entry in the table is applied at the first detected reel reset, the second entry at the second reset, and so on.
The default value for each entry is 100. Set each entry to the number of FFID records on the corresponding reel (i.e., the maximum FFID value on that reel) so that the offset makes the corrected FFID values continuous from reel to reel. If there are more detected reel resets than entries in the table, the module continues using the last entry value for all subsequent resets. Add one row per reel boundary — a dataset spanning three reels requires two entries.
If the Reels table is empty the module will report an error and no output will be produced. Always populate at least one entry before running.