Made to Order Software Corporation Logo
Home

SWF

SWF RGBA (swf_rgba)

SWF Structure Info
Tag Flash Version: 
1
SWF Structure: 
struct swf_rgba {
	unsigned char		f_red;
	unsigned char		f_green;
	unsigned char		f_blue;
	unsigned char		f_alpha;1
};
  • 1. 0 represent a fully transparent color, 255 represents a solid color.

The color components can be set to any value from 0 (no intensity) to maximum intensity (255).1

  • 1. For some PNG images, the red, green and blue colors may need to be multiplied by their alpha channel value before saved. Use the following formula to compute the proper values:

       f_red = orginal red * f_alpha / 255

SWF XRGB (swf_xrgb)

SWF Structure Info
Tag Flash Version: 
1
SWF Structure: 
struct swf_xrgb {
	unsigned char		f_pad;
	unsigned char		f_red;
	unsigned char		f_green;
	unsigned char		f_blue;
};

Images without an alpha channel which are saved using 32 bits (format 5) use XRGB colors.

The f_pad field should be set to zero or 255.

The color components can be set to any value from 0 (no intensity) to maximum intensity (255).

SWF RGB (swf_rgb)

SWF Structure Info
Tag Flash Version: 
1
SWF Structure: 
struct swf_rgb {
	unsigned char		f_red;
	unsigned char		f_green;
	unsigned char		f_blue;
};

Each color component is a value from 0 (no intensity) to 255 (full intensity).

DefineShape3

Tag Info
Tag Number: 
32
Tag Type: 
Define
Tag Flash Version: 
3
Brief Description: 

Brief Description: 

Define a simple geometric shape.

Tag Structure: 

Tag Structure: 
struct swf_defineshape {
	swf_tag				f_tag;		/* 2, 22, 32, 46, 83, or 84 */
	unsigned short			f_shape_id;
	swf_rect			f_rect;
	is_morph = f_tag == DefineMorphShape || f_tag == DefineMorphShape2;
	has_strokes = f_tag == DefineShape4 || f_tag == DefineMorphShape2;
	if(is_morph) {
		swf_rect			f_rect_morph;
	}
	if(has_strokes) {
		swf_rect			f_stroke_rect;
		if(is_morph) {
			swf_rect			f_stroke_rect_morph;
		}
		unsigned			f_define_shape_reserved : 6;
		unsigned			f_define_shape_non_scaling_strokes : 1;
		unsigned			f_define_shape_scaling_strokes : 1;
	}
	if(is_morph) {
		unsigned long			f_offset_morph;
		swf_morph_shape_with_style	f_morph_shape_with_style;
	}
	else {
		swf_shape_with_style		f_shape_with_style;
	}
};

These are probably the most important tags in this reference. They are used to define a shape using Bezier curves and lines with different styles. The DefineShape of V1.0 is usually enough unless you need a large number of styles or you want to specify colors with an alpha channel (RGBA).

The DefineMorphShape and DefineMorphShape2 can be used to render an intermediate shape between two defined shapes. All the points and control points of both shapes must match. This is because the rendering of the morphing shapes is just an interpolation between both shapes points and control points positions. The interpolation is a very simple linear function (note however that you still can use a non-linear transformation effect in the end.) Most of the parameters in a shape definition are doubled when this tag is used. It otherwise looks very similar.

The f_stroke_rect and f_stroke_rect_morph rectangles define the boundaries around their respective shapes without the line strokes (excluding the thickness of the line.)

The f_define_shape_non_scaling_strokes flag should be set to 1 if at least one of the line strokes always stays the same while morphing.

The f_define_shape_scaling_strokes flag should be set to 1 if at least one of the line strokes is changing while morphing.

The f_offset_morph 32 bits value gives the offset from after that value to the start of the second shape (the shape to morph to.) In other words, this value can be used to skip the styles and the first shape at once.

RemoveObject2

Tag Info
Tag Number: 
28
Tag Type: 
Display
Tag Flash Version: 
3
Brief Description: 

Remove the object at the specified level. This tag should be used in movies version 3 and over since it compressed better than the standard RemoveObject tag. Note that a PlaceObject2 can also be used for this task.

Tag Structure: 

Tag Structure: 
struct swf_removeobject {
	swf_tag			f_tag;		/* 5 or 28 */
	if(f_tag == RemoveObject) {
		unsigned short		f_object_id_ref;
	}
	unsigned short		f_depth;
};

Remove the specified object from the display list. If the same object was placed multiple times at the specified depth1 only the last copy is removed. When only a depth is specified, the last object placed at that depth is removed from the list. Note that since version 3 it is possible to use the PlaceObject2 in order to replace an object at a given depth without having to remove it first.

  • 1. It is illegal, yet possible, to place more than one object at the same depth.

Protect

Tag Info
Tag Number: 
24
Tag Type: 
Define
Tag Flash Version: 
2
Brief Description: 

Disable edition capabilities of the given SWF file. Though this doesn't need to be enforced by an SWF editor, it marks the file as being copyrighted in a way.

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

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.
See Also: 
EnableDebugger
EnableDebugger2

The protection tag is totally useless. The SWF format is an open format, otherwise how would you have so many players and tools to work with SWF movies? Thus, you can pretend to protect your movies, but anyone with a simple binary editor can transform the tag and make it another which has no such effect. Also, swf_dump and some other tools (such as flasm) can read your movie anyway.

For the sake of defining what you have in each tag, there are the protection tags fully described.

According to Macromedia, you can find some free implementation of the MD5 algorithm by Poul-Henning Kamp in ...

DefineShape2

Tag Info
Tag Number: 
22
Tag Type: 
Define
Tag Flash Version: 
2
Brief Description: 

Brief Description: 

Define a simple geometric shape.

Tag Structure: 

Tag Structure: 
struct swf_defineshape {
	swf_tag				f_tag;		/* 2, 22, 32, 46, 83, or 84 */
	unsigned short			f_shape_id;
	swf_rect			f_rect;
	is_morph = f_tag == DefineMorphShape || f_tag == DefineMorphShape2;
	has_strokes = f_tag == DefineShape4 || f_tag == DefineMorphShape2;
	if(is_morph) {
		swf_rect			f_rect_morph;
	}
	if(has_strokes) {
		swf_rect			f_stroke_rect;
		if(is_morph) {
			swf_rect			f_stroke_rect_morph;
		}
		unsigned			f_define_shape_reserved : 6;
		unsigned			f_define_shape_non_scaling_strokes : 1;
		unsigned			f_define_shape_scaling_strokes : 1;
	}
	if(is_morph) {
		unsigned long			f_offset_morph;
		swf_morph_shape_with_style	f_morph_shape_with_style;
	}
	else {
		swf_shape_with_style		f_shape_with_style;
	}
};

These are probably the most important tags in this reference. They are used to define a shape using Bezier curves and lines with different styles. The DefineShape of V1.0 is usually enough unless you need a large number of styles or you want to specify colors with an alpha channel (RGBA).

The DefineMorphShape and DefineMorphShape2 can be used to render an intermediate shape between two defined shapes. All the points and control points of both shapes must match. This is because the rendering of the morphing shapes is just an interpolation between both shapes points and control points positions. The interpolation is a very simple linear function (note however that you still can use a non-linear transformation effect in the end.) Most of the parameters in a shape definition are doubled when this tag is used. It otherwise looks very similar.

The f_stroke_rect and f_stroke_rect_morph rectangles define the boundaries around their respective shapes without the line strokes (excluding the thickness of the line.)

The f_define_shape_non_scaling_strokes flag should be set to 1 if at least one of the line strokes always stays the same while morphing.

The f_define_shape_scaling_strokes flag should be set to 1 if at least one of the line strokes is changing while morphing.

The f_offset_morph 32 bits value gives the offset from after that value to the start of the second shape (the shape to morph to.) In other words, this value can be used to skip the styles and the first shape at once.

DefineBitsJPEG2

Tag Info
Tag Number: 
21
Tag Type: 
Define
Tag Flash Version: 
2
Brief Description: 

Defines a complete JPEG image (includes the bit stream and the tables all in one thus enabling multiple tables to be used within the same SWF file).

Since Flash version 10, the data can also be set to a valid PNG or GIF89a. There is no need to specify the image format in the tag since the data describing the image includes the necessary information.

Tag Structure: 

Tag Structure: 
struct swf_definebitsjpeg {
	swf_long_tag		f_tag;		/* 6, 21, 35 or 90 */
	unsigned short		f_image_id;
	if(f_tag == DefineBitsJPEG3 + f_tag == DefineBitsJPEG4) {
		/* sizeof(f_encoding_tables) + sizeof(f_image_data) + 2 when JPEG4 */
		unsigned long		f_offset_to_alpha;
	}
	if(f_tag == DefineBitsJPEG4) {
		unsigned short fixed	f_deblocking_filter_parameter;
	}
	if(f_tag != DefineBitsJPEG) {
		/* when DefineBitsJPEG, use JPEGTables instead */
		unsigned char		f_encoding_tables[<variable size>];
	}
	unsigned char		f_image_data[<variable size>];
	if(f_tag == DefineBitsJPEG3 || f_tag == DefineBitsJPEG41) {
		unsigned char		f_alpha[<variable size>];
	}
};
  • 1. JPEG4 optionally accepts the f_alpha field. [To be verified]

See Also: 
DefineBitsJPEG
DefineBitsJPEG3
DefineBitsJPEG4
DefineBitsLossless
DefineBitsLossless2
JPEGTables

These tags define an image saved using the JPEG compression scheme.

DefineBitsJPEG (V1.0) does not include the encoding tables which are defined in the unique JPEGTables tag instead. All the DefineBitsJPEG of an SWF file use the only JPEGTables tag. Yes... This means you need a tool that is capable of reusing the same tables over and over again to make sure that all your DefineBitsJPEGs work properly (or use it just once.)

The other tags incorporate their own version of the JPEG encoding tables.

The DefineBitsJPEG3 and DefineBitsJPEG4 support an alpha channel bit plane (8 bits.) This alpha channel is compressed using the ZLIB scheme as defined with the DefineBitsLossless image formats and appears at the end.

With Flash 10, DefineBitsJPEG4 was introduced to support a deblocking filter parameter. This parameter should be set to a value between 0.0 and 1.0 (0x0000 and 0x0100--so really a value from 0 to 256 inclusive.)

WARNING: These tags require you to save the swf_tag in long format (i.e. f_tag_and_size & 0x3F == 0x3F even if the size is smaller.)

f_encoding should include 0xFF 0xDB and 0xFF 0xC4 entries.

The f_image_data buffer should include the 0xFF 0xE0, 0xFF 0xC0 and 0xFF 0xDA.

Since Flash 10 the f_encoding and f_image_data fields defined in the DefineBitsJPEG2, DefineBitsJPEG3 and DefineBitsJPEG4 tags, are viewed as one single large buffer and thus it can be a verbatim JPEG, PNG or GIF89a file.

When the buffer represents a JPEG, it starts with 0xFF 0xD8 and ends with 0xFF 0xD9.

When the buffer represents a PNG, it starts with 0x89 0x50 'P' 0x4E 'N' 0x47 'G' 0x0D '\r' 0x0A '\n' 0x1A '^Z' 0x0A '\n'.

When the buffer represents a GIF89a, it starts with 0x47 'G' 0x49 'I' 0x46 'F' 0x38 '8' 0x39 '9' 0x61 'a'.

WARNING: Up to Flash 7, both buffers (f_encoding and f_image_data) need to start with a 0xFF 0xD8 (SOI) and end with 0xFF 0xD9 (EOI). Since Flash 8, this practice should not be used anymore.

The f_alpha buffer is compressed with ZLIB as defined in the DefineBitsLossless tag (this is similar to the PNG format). WARNING: this field only works with JPEG data. A PNG or GIF89a cannot make use of this field (but they can make use of their own alpha channel.)

Note:   The Flash 10 documentation says that the f_alpha field is optional. This means you can save a JPEG in a DefineBitsJPEG4 without the Alpha Channel but still make use of the deblocking filter parameter. Before Flash 10, use DefineBitsJPEG2 instead (safer).

The DefineBitsJPEG tag may fail if it includes any encoding tables. These tables shall be defined within the JPEGTables instead.

Note that the Adobe SWF player better enforces the correctness of these tags since version 8. Some older movies may not work properly with Flash Player 8+.

DefineBitsLossless

Tag Info
Tag Number: 
20
Tag Type: 
Define
Tag Flash Version: 
2
Brief Description: 

A bitmap compressed using ZLIB (similar to the PNG format).

Tag Structure: 
struct swf_definebitslossless {
	swf_long_tag		f_tag;		/* 20 or 36 */
	unsigned short		f_image_id;
	unsigned char		f_format;	/* 3, 4 or 5 */
	unsigned short		f_width;
	unsigned short		f_height;
	if(f_format == 3) {
		unsigned char	f_colormap_count;
		if(f_tag == DefineBitsLossless) {
			swf_rgb		f_colormap[f_colormap_count];
		}
		else {
			swf_rgba	f_colormap[f_colormap_count];
		}
		unsigned char	f_indices[((f_width + 3) & -4) * f_height];
	}
	else {
		if(f_tag == DefineBitsLossless) {
			swf_xrgb	f_bitmap[f_width * f_height];
		}
		else {
			swf_argb	f_bitmap[f_width * f_height];
		}
	}
};
See Also: 
DefineBitsJPEG
DefineBitsJPEG2
DefineBitsJPEG3
DefineBitsJPEG4
DefineBitsLossless2
JPEGTables

These tags declares a loss-less image bitmap. It has a small header followed by an optional colormap and the bitmap data. When we have a colormap, the bitmap data is an array of indices in the colormap aligned to 4 bytes on a per row basis.

There are three supported formats:

...
Format
No.
(bits)		 Color Format Comments
Without
Alpha		 With
Alpha
3
(8 bits(1))		 RGB

SoundStreamBlock

Tag Info
Tag Number: 
19
Tag Type: 
Define
Tag Flash Version: 
2
Brief Description: 

A block of sound data (i.e. audio samples.) The size of this block of data is defined in the previous SoundStreamHead tag. It is used to download sound samples on a per frame basis instead of all at once.

Tag Structure: 
struct swf_soundstreamblock {
	swf_long_tag		f_tag;		/* 19 */
	unsigned char		f_sound_data[variable size];
};

The SoundStreamBlock tag defines the data of a sound effect previously defined with a SoundStreamHead or a SoundStreamHead2 tag.

WARNING: This tag requires you to save the swf_tag structure in long format whatever the size of the data (i.e. f_tag_and_size & 0x3F == 0x3F always true even if the size is 62 or less.)

The data depends on the SoundStreamHead[2] definition and is variable in size. Please, see the DefineSound tag for more information about sound data.