Within the live stream processing pipeline, the transcoder module is in charge of converting an incoming RTMP stream into the HLS format with multiple variants (e.g., 1080p, 720p, etc.). These variants have different bitrates so that viewers with different levels of download bandwidth are able to consume live video streams at the best possible quality for their connection.
x264opts specifies libx264 specific options. Here, IDR interval should be 2 * your desired FPS, so 720p60 would yield an IDR interval of 120 while 720p30 would require an IDR interval of 60. No-scenecut is used to disable scene change detection
The I of the Storm 720p
The two transcoded variants 720p60 and 720p30 in this example can share one scaler. As gathered from experiments, scaling is a very computationally expensive step in the transcoding pipeline. Avoiding the unnecessary repeated scaling process altogether can significantly optimize the performance of our transcoder. Figure 8 depicts a threading model of combining the scalers of 720p60 and 720p30 variants.
Our typical incoming bitstreams have 60fps (frames per second), and we transcode them to 30fps for lower bit-rate variants (e.g., 720p30, 480p30, etc.). On the other hand, since Twitch is a global platform, we often receive incoming streams of 50fps, most of which are from PAL countries. In this case, the lower bit-rate variant should be downsampled to 25fps, instead of 30fps.
Dear Maylene, I cameto Moore, Oklahoma, to do a piece on thetornado, to capture stories of pain andloss on the one hand as well as human kindnessand service on the other in the wake ofthat amazing storm.
I was working at PlazaTowers Elementary School when the tornado struck. Four of my kids werein the school, too. I laid my body over agroup of kindergartners as debris rushed around us. The roof came off, andthe storm completely destroyed the school. I was rushed to the hospital. And for nine hours, I didn'tknow whether all of my kids were alive.
When I was downvisiting Oklahoma and saw the impact thatthe tornado of May 2013 had on so many lives,the words to a hymn were rolling through my mind: "God moves in a mysterious way His wonders to perform; He plants hisfootsteps in the sea And rides upon the storm.
Ye fearful Saints,fresh courage take; The clouds ye so much dread Are big with mercyand shall break in blessings on your head." My whole life, Ihad felt abandoned, like there were pieces missing. After the storm, Godanswered my prayers. He picked up the piecesand filled that void. I don't ever have to feellike I'm going to be alone or abandoned again,because He's going to be there for meevery step of the way.
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