This paper presents an analysis of the scalability of the parallel video decoding on heterogeneous many core architectures. As benchmark, we use a highly parallel H.264/AVC video decoder that generates a large number of independent tasks. In order to translate task-level parallelism into performance gains both the video decoder and the architecture have been optimized. The video decoder was modified for exploiting coarse-grain frame-level parallelism in the entropy decoding kernel which has been considered the main bottleneck. Second, a heterogeneous combination of cores is evaluated for executing different type of tasks. Finally, an evaluation of the memory requirements of the whole system has been carried out. Experiments conducted using a trace-driven simulation methodology shows that the evaluated system exhibits a good parallel scalability up to 68 cores. At this point the parallel video decoder is able to decode more than 200 HD frames per second using simple low power processors.