Jovian Logic VI

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(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...")
 
(Software)
 
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|released=≤1988
 
|released=≤1988
 
}}
 
}}
'''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, paletted, and probably grayscale images.
+
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}}

Latest revision as of 16:11, 4 December 2016

File Format
Name Jovian Logic VI
Ontology
Extension(s) .vi
Released ≤1988

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.

[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)
0x11 = RGB, 24 bits/pixel
0x20 = grayscale, 4 bits/pixel
0x21 = grayscale, 6 bits/pixel
0x22 = grayscale, 8 bits/pixel
0x23 = grayscale, 1 bit/pixel
0x30 = palette color, 8 bits/pixel
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)
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.

[edit] Software

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