It seems that abc videos are divided into two categories.
As for the videos in the "section", you can get an url ending up with .mp4, like the sample link mentioned above.
However, the videos in the category of "show" are very different.
Firstly, you have to get an ip identified as in The US, and you can get the video played.
Secondly, those videos are going in html5 .
Take the following program for example:
http://abcnews.go.com/watch/good-mor...otas-prom-date
I can only get an url like this :
http://content.uplynk.com/c4349d38ed...d89d6dcb2.m3u8
There is no link ending with .mp4 at all.