Resizing 704x480i keeping correct aspect ratio

[wbo]

I have been capturing HDTV transport streams and encoding them using xvid for archiving. Up until now all the streams I have been working with have been 1920x1080i telecined film. So, I have been using AVISynth along with Decomb to restore the progressive frames and resizing to 1280x720 before encoding.

Now I have several 704x480i transport streams that I also want to encode with xvid. However, I am not sure what the proper pixel aspect ratio is for 704x480i DTV streams.

I know that 1920x1080 streams have a 1:1 pixel aspect ratio (1920/1080 = 16/9). But 704/480 does not equal 4/3 or even the NTSC equivalent of 3/2. Are 704x480i streams supposed to have a 1:1 pixel aspect ratio?

I would like to encode the strings with a 1:1 pixel aspect ratio for playback on a PC monitor, so I need to know what the pixel aspect ratio of the streams are so I can calculate what resolution I should resize them to. If the streams were NTSC 720x480 I would of course resize them to 640x480, but I am not sure what I should do with the 704x480i streams.

[Ishan]

If the streams were NTSC 720x480 I would of course resize them to 640x480

Well i'm sorry to says that but it's where you are wrong. To get the correct aspect ratio with a 720x480 stream you MUST cut 8 pixel each side of the picture THEN resize to 640x480 (it's in the standard for brodcast NTSC stream if I remember). It also means you can safely resize those 704x480 stream to 640x480 :)

[wbo]

Ishan, thanks for taking the time to answer my stupid questions :) Resizing to 640x480 does appear to make sense for 704x480i streams. Have a nice day,