Jovian Logic VI
(Created page with "{{FormatInfo |formattype=electronic |subcat=Graphics |extensions={{ext|vi}} |released=≤1988 }} '''Jovian Logic VI''' is a raster image format associated with Jovian Logic vi...") |
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| − | '''Jovian Logic VI''' is a raster image format associated with Jovian Logic video capture boards (maybe the "VIA" models in particular?). It is difficult to find any authoritative information about it. | + | '''Jovian Logic VI''' (or '''Jovian VI''') is a raster image format associated with Jovian Logic video capture boards (maybe the "VIA" models in particular?). It is difficult to find any authoritative information about it. |
| − | It appears to be a relatively simple uncompressed format, with a 16-byte header. It supports truecolor, | + | It appears to be a relatively simple uncompressed format, with a 16-byte header. It supports truecolor, grayscale, and paletted images. |
== Identification == | == Identification == | ||
Files apparently begin with the ASCII signature "{{magic|VI}}". | Files apparently begin with the ASCII signature "{{magic|VI}}". | ||
| + | |||
| + | == Format details == | ||
| + | ''This information is based on reverse engineering and guesswork. It may not be correct.'' | ||
| + | |||
| + | Multi-byte integers are little-endian. Offsets are in bytes, from the beginning of the file. | ||
| + | |||
| + | {| class="wikitable" | ||
| + | ! Offset !! Length !! Field !! Details | ||
| + | |- | ||
| + | |0 || 2 || signature || Always 0x56 0x49 (ASCII "VI") | ||
| + | |- | ||
| + | |2 || 1 || image_type || | ||
| + | 0x10 = RGB, 16 bits/pixel (R5-G6-B5)<br> | ||
| + | 0x11 = RGB, 24 bits/pixel<br> | ||
| + | 0x20 = grayscale, 4 bits/pixel<br> | ||
| + | 0x21 = grayscale, 6 bits/pixel<br> | ||
| + | 0x22 = grayscale, 8 bits/pixel<br> | ||
| + | 0x23 = grayscale, 1 bit/pixel<br> | ||
| + | 0x30 = palette color, 8 bits/pixel<br> | ||
| + | 0x31 = palette color, 4 bits/pixel | ||
| + | |- | ||
| + | |3 || 2 || width || Image width in pixels | ||
| + | |- | ||
| + | |5 || 2 || height || Image height in pixels | ||
| + | |- | ||
| + | |7 || 2 || ? || Unknown purpose. Can be 0. | ||
| + | |- | ||
| + | |9 || 1 || pal_code || | ||
| + | 0 = Palette entries have 6 bits/sample (18-bit color)<br> | ||
| + | nonzero = Palette entries have 8 bits/sample (24-bit color) | ||
| + | |- | ||
| + | |10 || 1 || pal_first_index || Index of the first palette entry stored in the file (typically 0) | ||
| + | |- | ||
| + | |11 || 1 || pal_length || Number of palette entries stored in the file. 0 means 256. | ||
| + | |- | ||
| + | |12 || 2 || pal_offset || Offset of the palette data | ||
| + | |- | ||
| + | |14 || 2 || image_offset || Offset of the image data | ||
| + | |- | ||
| + | |pal_offset || pal_length×3 || palette_data || Only present for paletted images. | ||
| + | |- | ||
| + | |image_offset || || image_data | ||
| + | |Pixels are in left-to-right, top-to-bottom order. Rows are padded to the next byte boundary. | ||
| + | |} | ||
== Software == | == Software == | ||
* [[XnView]] | * [[XnView]] | ||
* [[Image Alchemy]] | * [[Image Alchemy]] | ||
| + | * {{Deark}} | ||
| + | |||
| + | == Sample files == | ||
| + | * {{DexvertSamples|image/jovianLogicVI}} | ||
Latest revision as of 18:22, 6 June 2025
Jovian Logic VI (or Jovian VI) is a raster image format associated with Jovian Logic video capture boards (maybe the "VIA" models in particular?). It is difficult to find any authoritative information about it.
It appears to be a relatively simple uncompressed format, with a 16-byte header. It supports truecolor, grayscale, and paletted images.
Contents |
[edit] Identification
Files apparently begin with the ASCII signature "VI".
[edit] Format details
This information is based on reverse engineering and guesswork. It may not be correct.
Multi-byte integers are little-endian. Offsets are in bytes, from the beginning of the file.
| Offset | Length | Field | Details |
|---|---|---|---|
| 0 | 2 | signature | Always 0x56 0x49 (ASCII "VI") |
| 2 | 1 | image_type |
0x10 = RGB, 16 bits/pixel (R5-G6-B5) |
| 3 | 2 | width | Image width in pixels |
| 5 | 2 | height | Image height in pixels |
| 7 | 2 | ? | Unknown purpose. Can be 0. |
| 9 | 1 | pal_code |
0 = Palette entries have 6 bits/sample (18-bit color) |
| 10 | 1 | pal_first_index | Index of the first palette entry stored in the file (typically 0) |
| 11 | 1 | pal_length | Number of palette entries stored in the file. 0 means 256. |
| 12 | 2 | pal_offset | Offset of the palette data |
| 14 | 2 | image_offset | Offset of the image data |
| pal_offset | pal_length×3 | palette_data | Only present for paletted images. |
| image_offset | image_data | Pixels are in left-to-right, top-to-bottom order. Rows are padded to the next byte boundary. |
