Flex: computeSpectrum with streaming media?

I have a Flex3 app I wrote and I'm streaming audio over RTMP from a Red5 server. I'd love to be able to use SoundMixer.computeSpectrum(), but the spectrum data is all zeros. In one location, Adobe writes that SoundMixer.computeSpectrum() does not work with RTMP data:

"For media loaded from RTMP sources, you cannot use the BitmapData.draw() and SoundMixer.computeSpectrum() methods to extract run-time graphics and sound data." http://livedocs.adobe.com/flash/9.0/main/wwhelp/wwhimpl/common/html/wwhelp.htm?context=LiveDocs_Parts&file=00000353.html

Clear enough. Except, there's the actual doc开发者_开发百科umentation for computeSpectrum():

"In addition, this method cannot be used to extract data from RTMP streams, even when it is called by content that reside in the same domain as the RTMP server. [...] This method is supported over RTMP in Flash Player 9.0.115.0 and later and in Adobe AIR."

Ummm. That seems contradictory to me.

Any advice one way or the other?

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Here is an overall blog post on the subject: http://fefranca.com/blog/?p=6 And here is a proposed fix for Red5: http://osflash.org/pipermail/red5_osflash.org/2009-November/038844.html

<bean id="rtmpSampleAccess" class="org.red5.server.stream.RtmpSampleAccess">
    <property name="audioAllowed" value="true"/>
    <property name="videoAllowed" value="true"/>
</bean>

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There is also the 'client.allowAudioSampleAccess' property on server-side (Flash Media Server scripts), which allows clients to, as far as I understood, do exactly what you want - read audio sample data by the 'computeSpectrum' method.

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computeSpectrum and ID3 tags doesnt work with data from other domain than where flex application is located.

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Quoting Adobes own public document "Programming Adobe ActionScript 3.0 for Flash", page 700 (chapter 32, heading "Loading content", sub-heading "Content delivered using RTMP servers":

For media loaded from RTMP sources, you cannot use the BitmapData.draw() and SoundMixer.computeSpectrum() methods to extract run-time graphics and sound data.

The good old RTFM (Read The Friendly Manual) piece of advice still applies.