Intra-to-Inter Ratio (RA)

RA is the ratio of the encoded intra macro-blocs to those encoded as inter, hence it is expected that this parameter has benefic effect when it increases. This is clearly shown in Figs. 7.7, 7.10, 7.12 and 7.13. Its effect is more important than FR's, and more interestingly, for lower values of the BR parameter. This is shown in Figure 7.7, where for BR=0.15 the quality increased from 3.4 up to 4.6. This improvement is relatively important when the network bandwidth is small, but for larger BR, the effect is negligible. The two parameters LR and RA are related, as shown in Figure 7.12. For smaller LR, there is an improvement on the quality for the increase in RA. But this improvement vanishes when the LR increases. This means that we can get better video quality when the available channel bandwidth (BR) is small and for smaller values of LR by increasing the value of RA. In such a case, the effect of RA on the quality is more benefic than that of FR, as shown in Figure 7.14.

Figure 7.12: The impact of LR and RA on video quality.

  

Figure 7.13: The impact of CLP and RA on video quality.

Figure 7.14: RA is more benefic than FR for lower values of BR.