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

Question

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

Answer 1

Hi Jozsef,
thanks for your answer. In which version and on which date will the CBR be implemented? Flash Player 12? Or a minor release of FP11?
And until then I have no chance to have a constant bitrate? The bitrate I am passing to Camera.setQuality will just be ignored? Or is there any workaround?
Thanks and I will test using RTMFP instead of RTMP, but the CBR is the most important thing for us.
Best