ffmpeg is awesome. However, there are some issues that all ffmpeg-based players share that I wish someone would tackle (either by fixing ffmpeg or making something new). Seeking performance and reliability (especially single frame seeking) is a big one. Robustness in the face of truncated or otherwise corrupted video files is another. Ffmpeg isn't terrible in these areas, and I realize that there are underlying issues that make these things very hard, but still I believe it is possible to do much better.