SWF | Made to Order Software Corporation

FileAttributes

Tag Info

Tag Number:

69

Tag Type:

Format

Tag Flash Version:

8

Brief Description:

Since version 8, this tag is required and needs to be the very first tag in the movie. It is used as a way to better handle security within the Flash Player.

Tag Structure:

struct swf_fileattributes {
	swf_tag			f_tag;		/* 69 */
	unsigned		f_reserved : 3;
	unsigned		f_has_metadata : 1;
	unsigned		f_allow_abc : 1;	/* since V9.0 */
	unsigned		f_suppress_cross_domain_caching : 1;	/* since V9.0 */
	unsigned		f_swf_relative_urls : 1;	/* since V9.0 */
	unsigned		f_use_network : 1;
	unsigned		f_reserved : 24;
};

The FileAttributes tag is new to version 8. It must be present in all movies version 8 and over. It must be the very first tag in the SWF movie. It should be unique (other instances will be ignored.)

The f_has_metadata flag shall be set to 1 whenever the movie includes a Metadata tag.

The f_allow_abc flag shall be set to 1 to give the player the right to execute DoABC scripts (this is a version 9 flag, in version 8, keep it set to 0.)

The f_suppress_cross_domain_caching must have some effect over the caching of some things... (version 9+)

The f_swf_relative_urls means that URLs specified ...

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ScriptLimits

Tag Info

Tag Number:

65

Tag Type:

Define

Tag Flash Version:

7

Brief Description:

Change limits used to ensure scripts do not use more resources than what you choose. In version 7, it supports a maximum recursive depth and a maximum amount of time scripts can be run for in seconds.

Tag Structure:

struct swf_scriptlimits {
	swf_tag			f_tag;		/* 65 */
	unsigned short		f_max_recursion_depth;
	unsigned short		f_timeout_seconds;
};

This tag is used to change the default limits of script execution.

The maximum recursion depth is 256 by default. Any value, except zero (0) is valid.

The f_timeout_seconds parameter specifies the number of seconds before the players opens a dialog box saying that the SWF animation is stuck.

ScriptLimits

EnableDebugger2

Tag Info

Tag Number:

64

Tag Type:

Format

Tag Flash Version:

6

Brief Description:

The data of this tag is a 16 bits word followed by an MD5 password like the EnableDebugger tag. When it exists and you know the password, you will be given the right to debug the movie with Flash V6.x and over.

WARNING: this tag is only valid in Flash V6.x and over, use the EnableDebugger instead in V5.x and Protect in older movies (V2.x, V3.x, and V4.x).

Tag Structure:

struct swf_protect {
	swf_tag			f_tag;		/* 24, 58 or 64  */
	if(version >= 5) {
		if(tag == ProtectDebug2) {
			unsigned short	f_reserved;1
		}
		/* the password is optional when tag == Protect */
		string		f_md5_password;
	}
};

1. f_reserved must be set to zero.

DebugID

Tag Info

Tag Number:

63

Tag Type:

Define

Tag Flash Version:

6

Brief Description:

This tag is used when debugging an SWF movie. It gives information about what debug file to load to match the SWF movie with the source. The identifier is a UUID.

Tag Structure:

struct swf_debugid {
	swf_tag			f_tag;		/* 63 */
	unsigned char		f_uuid[<variable size>];
};

The DebugID tag is used to match a debug file (.swd) with a Flash animation (.swf). This is used by the Flash environment and is not required to create movies otherwise.

The f_uuid is a universally unique identifier. The size should be 128 bytes. It is otherwise defined by the size of the tag. All Unix and MS-Windows OSes offer a library to generate UUIDs. Although, you can very well just use a simple counter, it will work too.

DebugID

DefineFontInfo2

Tag Info

Tag Number:

62

Tag Type:

Define

Tag Flash Version:

6

Brief Description:

Defines information about a font, like the DefineFontInfo tag plus a language reference. To force the use of a given language, this tag should be used in v6.x+ movies instead of the DefineFontInfo tag.

Tag Structure:

struct swf_definefontinfo {
	swf_tag			f_tag;		/* 13 or 62 */
	unsigned short		f_font_info_id_ref;
	unsigned char		f_font_info_name_length;
	unsigned char		f_font_info_name[f_name_length];
	if(version >= 7 && f_tag.f_tag == DefineFontInfo2) {
		unsigned		f_font_info_reserved : 2;
		unsigned		f_font_info_small_text : 1;
		unsigned		f_font_info_reserved : 2;
	}
	else if(version >= 6 && f_tag.f_tag == DefineFontInfo2) {
		unsigned		f_font_info_reserved : 5;
	}
	else {
		unsigned		f_font_info_reserved : 2;
		unsigned		f_font_info_unicode : 1;
		unsigned		f_font_info_shiftjis : 1;
		unsigned		f_font_info_ansii : 1;
	}
	unsigned		f_font_info_italic : 1;
	unsigned		f_font_info_bold : 1;
	unsigned		f_font_info_wide : 1;	/* always 1 in v6.x+ */
	if(version >= 6 && f_tag.f_tag == DefineFontInfo2) {
		unsigned char		f_font_info_language;
	}
	if(f_font_info_wide) {
		unsigned short		f_font_info_map[f_font_glyphs_count];
	}
	else {
		unsigned char		f_font_info_map[f_font_glyphs_count];
	}
};

A DefineFontInfo tag will be used to complete the definition of a DefineFont tag. It uses the exact same identifier (f_font_info_id_ref = f_font_id). You must have the corresponding font definition appearing before the DefineFontInfo since it will use the number of glyphs defined in the DefineFont to know the size of the map definition in the DefineFontInfo tag.

When it looks like it perfectly matches an existing system font, the plugin may use that system font (as long as no rotation is used, it will work fine.) It is also possible to force the use of the system font by declaring an empty DefineFont tag (i.e. no glyph declaration at all.)

The use of system fonts usually ensures a much better quality of smaller prints. However, since version 8, there are many features in the Flash player taking care of really small fonts.

Note, however, that a system font (also called a device font) cannot be rotated. Also, the scaling and translation of a system font does not always respect the exact position. It is likely that the font will be moved to the next pixel left or right to avoid blurriness. That means it will look quite jaggedly when slowly moving such text.

The f_font_info_wide flag must be set to 1 in version 6 and over.

Note that the flag f_font_info_small_text of version 7+ is the same bit as the flag f_font_info_unicode in SWF version 5 or less.

Since version 6, the font name has to be encoded in UTF-8 instead of whatever encoding you want. It is also suggested that you use the DefineFontInfo2 tag instead.

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DefineVideoStream

Tag Info

Tag Number:

60

Tag Type:

Define

Tag Flash Version:

6

Brief Description:

Defines the necessary information for the player to display a video stream (i.e. size, codec, how to decode the data, etc.). Play the frames with VideoFrame tags.

Tag Structure:

struct swf_definevideostream {
	swf_tag			f_tag;		/* 60 */
	unsigned short		f_video_id;
	unsigned short		f_frame_count;
	unsigned short		f_width;	/* WARNING: this is in pixels */
	unsigned short		f_height;
	unsigned char		f_reserved : 5;
	unsigned char		f_deblocking : 2;
	unsigned char		f_smoothing : 1;
	unsigned char		f_codec;
};

This tag defines a video stream. To playback the video stream, one needs to add a list of VideoFrame tags.

The f_width and f_height are defined in pixels. This is rather uncommon in SWF so it is to be noted multiple times.

DoInitAction

Tag Info

Tag Number:

59

Tag Type:

Action

Tag Flash Version:

6

Brief Description:

Actions to perform the first time the following Show Frame tag is reached. All the initialization actions are executed before any other actions. You have to specify a sprite to which the actions are applied to. Thus you don't need a set target action. When multiple initialization action blocks are within the same frame, they are executed one after another in the order they appear in that frame.

Tag Structure:

struct swf_doaction {
	swf_tag			f_tag;		/* 12 and 59 */
	if(f_tag == DoInitAction) {
		unsigned short	f_action_sprite;
	}
	swf_action		f_action_record[variable];
};

The DoAction tag will be used to execute a set of actions in place. Usually, actions are used on buttons to add interactivity to the SWF movies. In version 1 you had only one dynamic branch (WaitForFrame). In version 4 you can test many different things such as a position, angle or sound track cursor position. Since version 5, SWF has a complete scripting language supporting string and arithmetic operations.

The DoInitAction tag is used when a sprite needs to be initialized. These actions are carried on the sprite only once. These are outside of the given sprite and will reference the sprite so all the actions are automatically applied to the sprite without you having to do a SetTarget.

The following describes the data in the DoAction and DoInitAction tags:

The f_action_sprite is a reference (identifier) to the sprite which will be initialized with the given actions.

The f_action_record is an array of actions terminated by an End action.

The following is a list of all the actions supported by SWF format. The Version tells you what version of Flash player you need in order to use the given action (otherwise it is likely to be ignored or worse, make the player crash). Note that Macromedia defines all the actions as being part of version 3 and over. Thus, any action mark as being available in earlier versions (version 1 or 2) may in fact not be (though the DoAction and DefineButton tags were part of version 1!!!)

The Length (Stacked) column specifies the length of the data following the property (only with the action ID is 0x80 to 0xFF) and what will be pushed onto the stack. All the expressions work as in polish notation: push the parameters, then execute an order that uses the data from the stack. The actions that do not push anything on the stack have nothing written between parenthesis.

The Data & Operation column specifies what data follows the action and what the operation is. If there is no data and no operation, then n.a. is used. The data will be described as a list of fields as in the other structures described in this document. The operations will be written as closely as possible to a C like operation (though strings are managed in a much different way than C!) Anything which is popped from the stack will be given a letter and a digit. The digit represents the count or position and the letter the type of the data (a count of 1 represents the first pop, a count of 2 represents the second pop, etc.) The following column (Comments) will explain how the operation uses the data when appropriate.

The data types used are as follow:

Short	Type
a	any type
b	boolean
f	foat
i	integer
n⁽¹⁾	numeric (integer or float)
o⁽²⁾	object (as in C++)
s	string
t	array or table of values
v	variable - pushes multiple values on the stack

⁽¹⁾ when I don't know whether an integer or a float should be specified I will use 'n' as well. This should be correct most of the time anyway.
⁽²⁾ an object reference can be obtained by evaluating the name of that object; thus GetVariable("carrot") will return a reference to the carrot object.

The following lists all the actions by name. Those that have the comment (typed) operates taking the type of its arguments in account as defined in ECMA-262 Section 11.6.1 (arithmetic), 11.8.5 (comparison), 11.9.3 (equality) which you can certainly find somewhere on the Internet. Version 3 is available here: ECMA-262 V3.0. The functions which are not typed will behave by (1) trying to transform parameters in values, then perform the operation with numbers only or (2) when strings cannot be transformed in values, perform a string operation.

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EnableDebugger

Tag Info

Tag Number:

58

Tag Type:

Format

Tag Flash Version:

5

Brief Description:

The data of this tag is an MD5 password like the EnableDebugger2 tag. When it exists and you know the password, you will be given the right to debug the movie with Flash V5.x and higher.

WARNING: this tag is only valid in Flash V5.x, use the EnableDebugger2 instead in V6.x and newer movies and Protect in older movies (V2.x, V3.x, and V4.x).

Tag Structure:

struct swf_protect {
	swf_tag			f_tag;		/* 24, 58 or 64  */
	if(version >= 5) {
		if(tag == ProtectDebug2) {
			unsigned short	f_reserved;1
		}
		/* the password is optional when tag == Protect */
		string		f_md5_password;
	}
};

1. f_reserved must be set to zero.

Import

Tag Info

Tag Number:

57

Tag Type:

Define

Tag Flash Version:

5

Brief Description:

Imports a list of definitions that are to be loaded from another movie. You can retrieve objects that were exported in the specified movie. You can have as many import as you like, though you should really only have one per referenced movie.

Tag Structure:

struct swf_import {
	swf_tag			f_tag;		/* 57 or 71  */
	string			f_url;
	if(version >= 8) {
		unsigned char		f_version;	/* must be set to 1 */
		unsigned char		f_reserved;
	}
	unsigned short		f_count;
	swf_external		f_symbol[f_count];
};

WARNING: in a Version 8 movie you MUST use an Import2 tag instead of Import or it just will not work (Import tags are ignored in version 8 movies).

Export

Tag Info

Tag Number:

56

Tag Type:

Define

Tag Flash Version:

5

Brief Description:

Exports a list of definitions declared external so they can be used in other movies. You can in this way create one or more movies to hold a collection of objects to be reused by other movies without having to duplicate these in each movie. A single export is enough for an entire movie (and you should have just one).

Tag Structure:

struct swf_export {
	swf_tag			f_tag;		/* 56 */
	unsigned short		f_count;
	swf_external		f_symbol[f_count];
};

The Export tag works in conjunction with the Import and Import2 tags. The Export tag gives a list of definitions made visible to the external world. Thus these definitions are in effect available to be imported by other movies.