STC / STX

Status

What it is

STC and STX appear in some embroidery conversion contexts but collide with other domains.

Satin Studio behavior

Satin Studio documents this format for identification and inspection. It does not open or export the file.

Versions and variants

Satin Studio checks the file signature and dialect rather than trusting the extension. An unrecognized version remains unopened, with the original file preserved for inspection.

File identification notes

Unknown.

Observed structure notes

• Observed STC readers skip 0x28 bytes of text-like design/stitch-count header, then read three-byte records.
• Observed STC records use signed X, signed Y, and a control byte. Control 0x01 stitches, 0x00 jumps, 25 ends, and other values are treated as needle changes by subtracting 2.
• Observed STX files begin with STX, contain little-endian offsets near the start, and point to an EXP-style stitch stream.

Structure sketch

STC and STX have separate observed shapes:

struct StcCandidate<'a> {
    text_header: [u8; 0x28],
    records: &'a [StcRecord],
}

struct StcRecord {
    dx: i8,
    dy: i8,
    control: u8,                       // 0x01 stitch, 0x00 jump, 25 end, otherwise needle = control - 2
}

struct StxCandidate<'a> {
    signature: [u8; 3],                // observed b"STX"
    header_rest: [u8; 0x09],
    color_start_offset: u32,
    unknown_block_offset: u32,
    stitch_start_offset: u32,
    exp_stitch_stream: &'a [u8],
}

Compatibility evidence

The notes above help identify and inspect the format; they do not imply import or export support. Keep the original file and record the machine and software that produced it.