KeithRB:
What do you mean by "TV signal"?
The only time that all the components are together is in the RF signal going into the Antenna. They are quickly separated into their separate "streams" and processed separately.
NTSC - Wikipedia
ATSC standards - Wikipedia
I realy don't know if use an Arduino is the best approach, but when the signal comes from the Antenna, i want to save all this streams in diferent files.
The video stream is not important now, but the audio and the text is.
I'm making a speech to text process, and I need a database from my country of the audio and the correct text of this audio...
So, I think if can I use Arduino to read this data from the Antenna.