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kaist-ina / NAS_public

This is an official repository of the paper, "Neural Adaptive Content-aware Internet Video Delivery"
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Ask a question about SSIM^(-1) in the paper #12

Closed howfars closed 3 years ago

howfars commented 3 years ago

In the part 5.3 of the paper,the function SSIM^(-1) was defined. The paper said "To create the mapping, we measure the SSIM of original video chunks at each bitrate (or resolution) and use piece-wise linear interpolation (e.g., (400 Kbps, SSIM1), ..., (4800 Kbps, SSIM5))". image And I have a question about this : When caculating the R_effective(C_n),we use the SSIM(-1) function to map a ssim value to a corresponding effective bitrate. However, the bitrate values are discrete, what if there are no corresponding bitrate for a ssim value in the mesurement data (400 Kbps, SSIM1), ..., (4800 Kbps, SSIM5)). For example, we have mesurement data like this: (400Kbps,SSIM1),(800Kbps,SSIM2)...(4800Kbps,SSIM5) Now we have a SR reconstructed chunk, whose SSIM value is greater than SSIM1 and less than SSIM2,then how do we get the effective bitrate of this chunk? Do you mean we can do a linear interpolation in those discrete mesurement data?

chaos5958 commented 3 years ago

Hi, thanks for interest in our paper!

In our experiment, we did a linear interpolation to get an effective bitrate. But, if you have more data, you can build a more precise function.

howfars commented 3 years ago

Thank you for your answer,it's very helpful!