I will be importing an NTSC DV signal through my fire wire port, so the video will be 740x480. I was wondering whether I should encode this to MPEG-1 at 740x480 or 352x240 using a bitrate of 2424Kb/s. Both would have the same bitrate. At 740 it would retain the same resolution but while strectching the bitrate, while at 352 the picture would be half the res. but would have a larger pipeline per pixel. I'm just wondering which will give me the better picture?

Thanks in advance.

-- Gene Williams (gene_williams@hotmail.com), March 10, 2000

Answers

Gene,

from experimenting with framesize and bitrates and play back on my Pioneer DVD players. 740x480 gives best resolution over the 1/2 frame. However, if you're planning to do the 740x480 frame size at the bitrates that you're encoding it, this will make your playback slow. I'd try it at around 2000 -2200kb/s(max).

-- lnguyen (wingstarzz@hotmail.com), March 10, 2000.

Gene, Mpeg/1 does not handle interlaced frames. Your source is interlaced. If you encode at full 480 scanlines, the encoder will merge the two fields of every frame, which believe me, will look awful.

Either use mpeg/2 (useless if you don't have hardware decoding) or, if you want to play it really weird, 740x240. But never go 480 for the vertical in mpeg/1.

-- Matias (mpetrel@fi.uba.ar), March 11, 2000.