Bitrate unstable on Twitch — how to ensure CBR is actually applied?

[noho501]

Hi,

I’m using RootEncoder for live streaming to Twitch.
I set bitrate = 4000 * 1000, and also tested with and without the bitrate adapter.
However, the Twitch dashboard shows the bitrate sometimes spikes up to 7000 kbps, causing instability and disconnections.

I checked the source code here:
https://github.com/pedroSG94/RootEncoder/blob/master/encoder/src/main/java/com/pedro/encoder/video/VideoEncoder.java#L154

// Set CBR mode if supported by encoder.
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP && CodecUtil.isCBRModeSupported(encoder, type)) {
    Log.i(TAG, "set bitrate mode CBR");
    videoFormat.setInteger(MediaFormat.KEY_BITRATE_MODE,
        MediaCodecInfo.EncoderCapabilities.BITRATE_MODE_CBR);
} else {
    Log.i(TAG, "bitrate mode CBR not supported using default mode");
}

From what I understand, it should automatically set CBR if supported —
but I’m not sure why, on stream start, the bitrate still jumps over 7 Mbps, triggering Twitch’s “high bitrate” warning and sometimes ending the stream.

Any advice would be appreciated.

Thanks.

[pedroSG94]

Hello,

I'm not sure about it but normally it is related with the codec implementation of your device. Try force software encode to know if that solves the problem.