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246 Chapter 10. Error Concealment Using Motion Field Interpolation

(a) Error free (b) No concealment

(c) Concealed using BM (d) Concealed using BM-MFI
Figure 10.10: Subjective quality of decoded and concealed frame of QSIF FOREMAN. The sequence
was H.263 encoded at 24 kbits=s and corrupted with a 10 −3 bit error rate

decoded and concealed sequences revealed that this poor performance is due
mainly to the e,ects of spatial and temporal error propagation and also to
the imperfections of the error detection approach. In addition, it was observed
that temporal techniques do not perform well for intracoded blocks, scene
changes, and uncovered backgrounds. Thus, despite their advantages, temporal
error concealment techniques must be combined with spatial error conceal-
ment and, more importantly, must be supported by some error containment
techniques, such as INTRA refresh.

10.5 Temporal Error Concealment for Multiple-
Reference Motion-Compensated Prediction

As already discussed, temporal error concealment is an important tool to
combat the e,ects of errors on transmitted video. A number of temporal error