This paper proposes a hash-based collaborative transcoding proxy system for heterogeneous client environment. The system aims to improve the system performance in two aspects, caching efficiency and workload balancing. This system employs a hash-based object caching strategy, which optimizes the cache storage utilization by removing redundant objects scattering in different locations of the system cache. In addition, cache replacement algorithm deployed at the transcoding proxy is examined. Conclusion is drawn that object access rate should be considered when making eviction decision. On the other hand, a hash-based workload distribution strategy is proposed to share the expensive transcoding load among proxies. This strategy performs well with balanced hash function. With unbalanced hash function, satisfactory load sharing is achieved by an optimized strategy, which allows the overloaded proxy to outsource some transcoding tasks to less overloaded neighbors.