STOS packed screen - Revision history

Jsummers: /* Discussion */

2025-06-11T06:24:45Z

‎Discussion

Jsummers: /* Sample files */

2024-06-26T20:59:24Z

‎Sample files

Jsummers: Created page with "{{FormatInfo |formattype=electronic |subcat=Graphics |subcat2=Atari graphics formats |extensions={{ext|pac}}, {{ext|mbk}}, others }} '''STOS packed screen''' is an Atari raste..."

2024-06-24T23:57:57Z

Created page with "{{FormatInfo |formattype=electronic |subcat=Graphics |subcat2=Atari graphics formats |extensions={{ext|pac}}, {{ext|mbk}}, others }} '''STOS packed screen''' is an Atari raste..."

New page

{{FormatInfo
|formattype=electronic
|subcat=Graphics
|subcat2=Atari graphics formats
|extensions={{ext|pac}}, {{ext|mbk}}, others
}}
'''STOS packed screen''' is an Atari raster graphics format. It is one of the "bank" formats used in [[STOS memory bank]] (MBK). This article explains some of the formats related to packed screen, some of which are also covered in other articles.

== Discussion ==
A packed screen can appear in an [[STOS memory bank|MBK]] container file, and maybe in other STOS formats. Or it can appear in a file by itself that starts with bytes <code>06 07 19 63</code>.

Independent of the container format, there are at least six different image formats. Unfortunately, there is not always a good way to tell which format a given image uses. The filename extension can help, but isn't always good enough.

== Format details ==
Internally, packed screen format is very similar to [[AMOS Picture Bank]], just with different rules for how many planes there can be, etc. The compression is a kind of [[Run-length encoding|RLE]], applied twice.

== Formats ==

{| class="wikitable"
! Format !! Res. code !! Planes !! Colors !! Remarks
|-
|Standard low res. || 0 || 4 || 16
|-
|Standard medium res. || 1 || 2 || 4 || Same as [[Picture Packer]] PP2.
|-
|Standard high res. || 2 || 1 || 2
|-
|Picture Packer PP1 || 1 || 2 || 16 || Refer to [[Picture Packer]].
|-
|Picture Packer PP3 || 1 || 2 || 2 || Refer to [[Picture Packer]].
|-
|"DAJ" 4-plane || 0 || 4 || 4 || Used by a viewer for the ST+ (ST Plus) Atari diskmagazine.
|}

The "resolution code", which implies the number of planes, is stored in the file. The number of colors is not.

== Identification ==

An MBK file containing a packed screen starts with "{{magic|Lionpoubnk}}", has a nonzero number (4-byte big endian) at offset 10, has byte (hex) <code>81</code> at offset 14, and bytes {{magic|06 07 19 63}} at offset 18. The signature at offset 18 is ''not'' sufficient by itself, because it also matches STOS character set files.

A raw packed screen file starts with bytes {{magic|06 07 19 63}}. Following that is <code>00 00</code>, or <code>00 01</code>, or <code>00 02</code>.

== Specifications ==
* {{AtariForumWiki|STOS.MBK|Atari Forum Wiki: STOS.MBK}}, section named "Banktype $81, data, magic $06071963, packed screen"

== Sample files ==
''(TODO)''

← Older revision		Revision as of 20:59, 26 June 2024
Line 45:		Line 45:

	== Sample files ==		== Sample files ==
−	''(~~TODO~~)''	+	* [https://archive.org/details/belgian-amiga-club-adf-collection Belgian Amiga Club - ADF Collection] → BS1 part 01.zip → Astate - La Malediction des Templiers[...].adf → dat/*.PAC (standard low res)
		+	* [https://archive.org/details/cdrom-nf-archive-10 No Fragments Archive 10: Diskmags] → MAGS/HIT_DISK/HD_89_2.MSA → DATA/*.MBK (standard low res and high res in MBK)
		+	* [https://archive.org/details/cdrom-nf-archive-10 No Fragments Archive 10: Diskmags] → MAGS/STOSSER/STOSSE23.MSA → STOSSER/*.MBK (standard low res and medium res in MBK)
		+	* [https://archive.org/details/cdrom-nf-archive-10 No Fragments Archive 10: Diskmags] → MAGS/LEDGERS/LEDG_08.MSA → ARTICLES/*.MBK (PP1 in MBK)
		+	* [https://archive.org/details/atarist-tce-f030-powercd-2 TCE Falcon 030 Power CD #2] → ST_STE/MAGS/STPLUS13.ARJ → stplus13.msa → ST+/*.DAJ (DAJ 4-plane and others)
		+
		+	See also [[Picture Packer#Sample files]].

@@ Line 8: / Line 8: @@
 == Discussion ==
-A packed screen can appear in an [[STOS memory bank|MBK]] container file, and maybe in other STOS formats. Or it can appear in a file by itself that starts with bytes <code>06 07 19 63</code>.
+A packed screen can appear in an [[STOS memory bank|MBK]] container file, and maybe in other STOS formats. Or it can appear in a file by itself that starts with bytes <code>06 07 19 63</code>. Note that some [[AMOS Picture Bank|AMOS picture]] files also start this way, and distinguishing the formats is not simple.
 Independent of the container format, there are at least six different image formats. Unfortunately, there is not always a good way to tell which format a given image uses. The filename extension can help, but isn't always good enough.