Exfo EXpert IPTV Test Tools (FTB-1 / 2 Pro) Manuel d'utilisateur télécharger pdf (Page 51)

A.1.2.1 Impact of Coding Bitrate on Video Quality

For a typical MPEG-2 encoded video stream with standard resolution 720x486, GOP sequence

IBBPBBPBBPBBPBB, at 30 frames per second, the mean square error (MSE) due to bitrate can

be approximated by:

MSE

= 0.00001 + 1.5 / (B + B

/ 30000).

Where B is the bitrate in kilobits per second. The corresponding peak signal-to-noise ratio

(PSNR) value for the frame can be computed by

PSNR

= -10 log10MSEbr.

Figure 2-4 shows the estimated PSNR value on coding bitrate for MPEG-2 encoded video.

Figure 2-4

Estimated

PSNR on

Coding Bitrate

for Standard

Definition

MPEG-2 Video

at 30 Frames

per Second

1 2 ... 46 47 48 49 50 51 52 53 54 55 56 ... 81 82

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Exfo EXpert IPTV Test Tools (FTB-1 / 2 Pro) Manuel d'utilisateur Page 51