Today I performed a benchmarking test with MediaCoder iPhone Edition which has got improved support for Intel MSDK recently, by transcoding the same 720p H.264 MKV file to a MP4 file of iPhone 4 profile. In order to obtain transcoded videos with near visual quality, x264 was set to fast preset and Intel MSDK encoder was set to balanced mode. The difference in transcoding speed and CPU utilization is significant. With x264, the CPU utilization is near 100% and the overall transcoding speed is approximately 3.4x (versus playback speed). When using Intel MSDK encoder, with computation off-loaded to CPU built-in GPU, the CPU utilization is near 50% and the overall speed is about 7.9x, which is 2.3 times of that of x264.
