SHV

Status

Field	Value
Extension(s)	.shv
Common ecosystem	Husqvarna Viking
Format family	Legacy machine file
Satin Studio status	Researching
Open / import	No
Export	No
Confidence	Medium.

What it is

SHV is a legacy Husqvarna Viking format associated with older media and possibly multi-design layouts.

Satin Studio direction

Watchlist import format if real user files appear.

Versions and variants

SHV may be more than a flat stitch stream because it can include substantial preview/graphic data and fixed-length stitch sections per color.

File identification notes

Reported structure includes stitch data, a large one-bit graphic of variable size, fixed/magic-number color lookup, x == 0x80 control events, and predefined stitch-data lengths before color switching.

Observed structure notes

• Observed SHV readers skip an 0x56-byte header text area, read a length-prefixed name, design width/height, skip a one-bit graphic region sized as ceil(height / 2) * width, then read color/stitch-count records.
• Each color section has a big-endian 32-bit stitch count, an 8-bit color code, and nine skipped bytes in observed readers. Color changes are inferred when the stitch count for the current color is exhausted.
• Observed stitch controls use 0x80 as a marker: 0x80 0x03 no-op, 0x80 0x02 leaves jump mode, and 0x80 0x01 is followed by signed 16-bit big-endian movement and enters jump mode.
• Observed SHV color changes are not explicit stitch opcodes; they are inferred from per-color stitch-count sections while reading the shared stitch stream.

Structure sketch

SHV combines metadata, a bitmap-like graphic, per-color stitch counts, and stitch records:

struct ShvFile<'a> {
    header_text: [u8; 0x56],
    name_len: u8,
    name: &'a [u8],
    design_width: u8,
    design_height: u8,
    graphic: &'a [u8],                 // ceil(height / 2) * width bytes after a short skip
    color_count: u8,
    color_sections: &'a [ShvColorSection],
    records: &'a [ShvRecord],
}

struct ShvColorSection {
    stitch_count: u32,                 // big-endian
    color_code: u8,
    unknown: [u8; 9],
}

enum ShvRecord {
    StitchOrJump { dx: i8, dy: i8 },
    NoOp,                              // 0x80 0x03
    EndJumpMode,                       // 0x80 0x02
    LongJump { dx: i16, dy: i16 },      // 0x80 0x01 + signed 16-bit BE x/y
}

What we still need

Legacy files, graphics layout, color lookup behavior, and reader validation.