Using a SMIL file -- Flash CS3

To handle multiple streams for multiple bandwidths, the VideoPlayer class uses a helper class (NCManager) that supports a subset of SMIL. SMIL is used identify the location of the video stream, the layout (width and height) of the FLV file, and the source FLV files that correspond to the different bandwidths. It can also be used to specify the bit rate and duration of the FLV file.

The following example shows a SMIL file that streams multiple bandwidth FLV files from a FMS using RTMP:

<smil>
    <head>
        <meta base="rtmp://myserver/myapp/" />
        <layout>
            <root-layout width="240" height="180" />
        </layout>
    </head>
    <body>
            <switch>
                    <ref src="myvideo_cable.flv" dur="3:00.1"/>
                    <video src="myvideo_isdn.flv" system-bitrate="128000" dur="3:00.1"/>
                    <video src="myvideo_mdm.flv" system-bitrate="56000"  dur="3:00.1"/>
            </switch>
    </body>
</smil>

The <head> tag may contain the <meta> and <layout> tags. The <meta> tag supports only the base attribute, which is used to specify the URL of the streaming video (RTMP from a FMS).

The <layout> tag supports only the root-layout element, which is used to set the height and width attributes, and, therefore, determines the size of the window in which the FLV file is rendered. These attributes accept only pixel values, not percentages.

Within the body of the SMIL file, you can either include a single link to a FLV source file or, if you're streaming multiple files for multiple bandwidths from a FMS (as in the previous example), you can use the <switch> tag to list the source files.

The video and ref tags within the <switch> tag are synonymous--they both can use the src attribute to specify FLV files. Further, each can use the region, system-bitrate, and dur attributes to specify the region, the minimum bandwidth required, and the duration of the FLV file.

Within the <body> tag, only one occurrence of either the <video>, <src>, or <switch> tags is allowed.

The following example shows a progressive download for a single FLV file that does not use bandwidth detection:

<smil>
        <head>
            <layout>
                <root-layout width="240" height="180" />
            </layout>
        </head>
        <body>
            <video src=""myvideo.flv" />
        </body>
</smil>