why iTunes can't play some MP4's video, but only audio?

Please help me troubleshoot MP4 playing problem in iTunes (want to play it eventually in iPod).

I downloaded 英語原人原唱歌曲視頻1000部（一) MP4 files and added them to iTunes Library/Movies. I could play some of them such as "25Minutes.mp4", but when I play some others like "(EverythingIDo)IDoItForYou.mp4", it only has audio played, but no video played.

I installed klcodec413fbeta.exe but seems it still doesn't work.

貧農家的長工 and other experts, any ideas why? Thanks in advance for help.