This youtube play list contains the hour-long CCTV series on Taijiquan, broken down in four parts:
This is a fairly well-made, comprehensive program about the principles of Taijiquan as explained by leading figures of the six major styles of contemporary Taijiquan: Chen (陈), Yang (杨), Wu (吴), Wuu (武), Sun (孙), He (和). The masters discuss and illustrate the complexities in such notions as relaxation (松), roundness (圆), softness (柔) and hardness (刚), stillness (静) and movement (动) as they pertain to general movement principles and martial applications in particular.
The show is done in Mandarin, so unfortunately if you’re not familar with some of the taiji history and principles already, it would be hard to guess what is being discussed, but for people who’ve been studying taiji with well-trained masters, it shouldn’t be hard to follow. Enjoy!