DefineVideoStream

Tag Info

Tag Number:

Tag Type:

Define

Tag Flash Version:

Unknown SWF Tag:

This tag is defined by the Flash documentation by Adobe

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.

The f_deblocking parameter can be set to one of the values defined in the following table. All videos are saved in small blocks of about 16x16 pixels (there are different sizes.) Turning this feature on lets the player mix colors between blocks for better output quality.

Number	Comments	SWF Version
0	Use video packet information	6
1	Always Off	6
2	Fast deblocking (in version 6 it meant: always on)	6
3	High Quality Deblocking	8
4	High Quality Deblocking and Fast Deringing	8
5	High Quality Deblocking and Deringing	8

The f_smoothing flag can be set to 1 to have the player smooth the video before rendering it on the output screen.

The f_codec number specifies the codec used to compress the video. At this time, the following are defined:

Number	Name	Comments	SWF Version
2	Sorenson H.263	Since Adobe took over Flash, they worked on making this format free of any royalties. In other words, you are free to encode and decode this video format in your commercial Flash animations.	6
3	Screen Video		7
4	VP6		8
5	VP6 with Alpha		8

DefineVideoStream

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