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Video: How Netflix Leverages VMAF, Part 2: Encoding Decisions

Learn more about VMAF at Streaming Media's next event.

Watch the complete video of this presentation from Streaming Media West, VMAF: The Journey Continues, in the Streaming Media Conference Video Portal.

Read the complete transcript of this clip:

Zhi Li: I’ll introduce the next topic, which is the encoding decision optimization using VMAF. We came out with this particular framework we called an “Optimizer.” We can process video and encoding on a per-shot basis. For each shot, we have multiple encodes we collect. This DynAmp optimizer deal will be able to find the best encoding path, that will give the best average VMAF quality, for a given bitrate.
By doing that, we'll be able to contract very similar diagram like this. As you can see, they're different colors representing different codecs.

Whether you're applying DynAmp optimization or not. For example, the green curve shows it's pushing the boundary of this distortion curve. You can see there is still space, a boundary to be pushed.

This framework can bring you benefits. The interesting part of this is that, if you look at the curve, it looks very similar to the ones we do for encoding comparisons.

So, very similarly, we can compute bitrate based on this curve. If you have the same DynAmp optimization applied to different encodes, we can, again, do a code and comparison, based on those results. The benefit of doing that is, in this case, we don't have to worry about what resolution you're comparing. Everything is folding to this one diagram, where you're really comparing at the operating reach, and that really matters in practice. Because, these are the ones you're going to be using in production.

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