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I am learning video processing and I have successfully implemented a video encoder based on JPEG algorithm (for spartial redundancy) and block matching algorithm (for temporal redundancy).

Now I am asked to discuss the PSNR behavior with respect to the bit-rate for different quality factors and block sizes.(Provide a graph)

The question made me so confused about what would be included in the graph and how to display such properties on a graph.

Can anyone give me some ideas?

Please forgive me if my English is poor.

Thank you very much!

Tai Christian
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1 Answers1

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The PSNR as a function of the bitrate is generally a concave function.

When you encode a video with your encoder, you get a PSNR value and a bitrate value. To get a curve, you need to vary your "quality factor", generally this can be the quantization parameter (QP).

Now you get multiple pairs (PSNR, bitrate), which allows you to plot the curves.

If you have to plot for different block sizes, you will need different curves.

Example below: enter image description here

damjeux
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  • So I am thinking about 2 figures. In the first figure, I choose a quality factor and vary the block size (as in your figure). In the second figure, I keep the block size and vary the quality factor. Do you think 2 figures will bring more meanings? Or only one is enough? – Tai Christian Jun 11 '16 at 13:00
  • You can try with two figures. I don't know what the outcome will be, but it might be interesting. – damjeux Jun 13 '16 at 09:38