Camera.setQuality() not working for H.264 enconding in Flash Player 11?

Hi,

I am using the new Flash Player 11 ability to encode the webcam video with H264 codec and send it via RTMP to a Flash Media Server. It works, but the bitrate of the video stream is not constant. Therefore the resulting stream is stuttering when playing back.

I tested it in two ways:

A) Encoding and sending the webcam video to FMS via FMLE -> very fluent playback

B) Encoding and sending the webcam video to FMS via Flash Player 11 (all setting for codec etc. are the same) -> playback is stuttering

As you can see in the screenshots below, the incoming bandwidth at FMS varies a lot. When using FMLE the incoming bitrate at the FMS is very constant:

In contrast: when using FP11, the bitrate jumps between 1000 and 6000 kbps during the whole stream:

That is definitely the reason why it "stutters" when using Flash Player 11. But I have no idea what I am doing wrong.

I am using these encoding settings for FP11 ...

var videoStreamSettings : H264VideoStreamSettings = new H264VideoStreamSettings();

videoStreamSettings.setKeyFrameInterval(5);

videoStreamSettings.setMode(1280,720, 25);

videoStreamSettings.setProfileLevel(H264Profile.BASELINE, H264Level.LEVEL_5_1);

videoStreamSettings.setQuality(1000000, 0);

... and these settings for the camera:

var camera : Camera = Camera.getCamera(0);

camera.setQuality(1000000, 0);

camera.setKeyFrameInterval(5);

camera.setMode(1280, 720, 25);

Any idea why the bandwith is not constant in FP11? The function camera.setQuality() should do the job, right (http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/fla sh/media/Camera.html#setQuality%28%29)? Is there any known bug for Camera.setQuality when using H.264 encoding in FP11?

Thanks a lot.

Malte