SEW

Status

What it is

SEW is an older Janome-family format used by some Janome, Elna, and Kenmore machines.

Satin Studio behavior

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

Versions and variants

SEW is a legacy Janome-family format. Machine-generation limits such as hoop size and stitch count need to be tracked with version or machine notes.

File identification notes

Reported structure uses signed x, y movement records, x == 0x80 control events, and color lookup through a fixed/magic-number thread table rather than arbitrary RGB metadata.

Observed structure notes

• Observed SEW files start with a little-endian color count and 16-bit color indexes into a fixed Janome-family palette.
• Observed readers seek to offset 0x1D78 for stitch data. Normal movement is signed two-byte dx, dy; first byte 0x80 introduces a control byte plus two payload bytes.
• Observed controls: low bit set means color change, 0x04 or 0x02 jump with payload movement, and 0x10 stitch/control marker with payload movement.
• Observed SEW stitch import depends on a fixed stitch-data offset; header bytes before 0x1D78 carry palette and machine metadata that remain underdocumented.

Structure sketch

Observed SEW files contain palette indexes and a fixed stitch-data offset:

struct SewFile<'a> {
    color_count: u16,
    palette_indexes: &'a [u16],
    padding_until_stitches: &'a [u8],   // stitch stream observed at offset 0x1D78
    records: &'a [SewRecord],
}

enum SewRecord {
    Stitch { dx: i8, dy: i8 },
    ColorChange,                       // marker 0x80, control bit 0x01 set
    Jump { dx: i8, dy: i8 },            // marker 0x80, control 0x04 or 0x02
    StitchControl { dx: i8, dy: i8 },   // marker 0x80, control 0x10
}

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.