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MediaLive not respecting RTMP Bitrate

0

I am using medialive and mediaconnect to restream srt streams to multiple destinations. I realized that the RTMP output is not respecting the bitrate specified and even sometimes is not respecting the resolution.

Is there a special setting to enable for it to output with the specified resolution and bitrate? Current setttings:

Width : 1920  Height: 1080 Codec: H264
Rate Control: CBR 6 500 000
Frame Rate: Specified 30000 / 1001 Progressive
GOP Size : 60 Frames B-Frames 0
Scaling Default AFD Passtrough

--> Received stream : 1920x1080 or 1280x720 / 1.3 to 1.6 mbps

** EDIT/UPDATE**

I tried to create a brand new channel from a workflow, selecting twitch as a destination but replacing the endpoint with my own RTMP destination. The only output option was 1080p@30/4.5mbps output. Didn't change anything except the endpoint. Start the flow.

And I'm still receiving 1.5mbps video. I was hoping to avoid rolling my own encoder to forward streams to our clients, but if there's no way to control the output of medialive, I don't see how I can achieve it witihin AWS.

  • B-Wilkinson
    4 years ago

    A few comments. Not sure why you have 0 B frames. B frames are needed for efficient compression. Either way not the problem you are having.

    I am almost certain that you did these tests with static content. RTMP generally ramps itself down when content is static such as color bars and a slate.

    I would define all aspect of the Media Live encode and not allow "same as source". Pixel shape should be 1 to 1.

    Semi curious how are you getting SRT into Media Live. The only way I can think of is through an SRT listen in Media Connect. Media Live does not accept SRT.

  • TechSol
    4 years ago

    Yes, sorry I was unclear. SRT in from mediaconnect, then vpc input from mediaconnect to medialive. I stream the same content from my computer to the RTMP destination, I get 1080p and 6.5mbps. I stream out of mediaconnect with SRT to my machine, I get 1080p. But when I do mymachine->mediaconnect->medialive->RTMP 3rd party provider. I get ~1.5mbps and sometimes 1280x720. Also, I tried with static content and moving text and the infamous twitch sync footage you can find somewhere on the internet. As for the B frames, it's been a habit to remove them to lower the lookahead as it would require the full GOP to be downloaded before being displayed. Not sure in this case it changes much though.

Topics
Media Services
Tags
AWS Elemental MediaLiveAWS Elemental MediaConnect
Language
English
asked 4 years ago259 views
1 Answer
0

Can you try to configure “Include Filler NAL Units” option in the RTMP output group: Applies only when the rate control mode (in the codec settings) is CBR (constant bit rate). Controls whether the RTMP output stream is padded (with FILL NAL units) in order to achieve a constant bit rate that is truly constant. When there is no padding, the bandwidth varies (up to the bitrate value in the codec settings). We recommend that you choose Auto.

AWS
answered a year ago

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