NTSC to PAL time differences

[IvIark]

HI

I don't consider myself a newbie as I've been working with digital video for many years now but I suppose that this is probably an easy question for someone to answer so thought it best in this category.
Coming from the UK I am not too interested in NTSC for the vast majority of the time and so am definitely not an expert in 29.97 or 23.976 framerates, or pulldown etc. Having said that, there are times when I will get a video in NTSC (AVI) that I want to convert to PAL (MPEG2) or vice versa.

I have noticed that some of the encoders out there keep the time exact when comparing the final output to the source, whereas some simply speed up (in the case of PAL to NTSC) or slow down (in the case of NTSC to PAL) the video, and yet I encoded an AVI yesterday using TMPGEnc and it turtned out to be exactly the same length as the source. This was AVI straight into TMPGEnc without using a frameserver.

So help me, what's that all about then?

[bugster]

In Tmpgenc, if you feed it an NTSC video and tell it to encode it in Pal it does what you describe. i.e. it ensures the total time of the video remains the same but encodes at 25 fps. Assuming a 23.97 fps source (NTSC film) it will convert to 25fps by adding the required number of extra frames. These frames are duplicates of the previous frame and the resulting video usually plays back a little jerkily. You can Tell Tmpgenc not to do this by checking the 'do not do frame rate conversion' optin on the settings advanced tab. In this case the length of the video will change according to the conversion.

One question that has to be asked though is do you really need to do this. All DVD players will play back PAL AND NTSC material. Whne playing NTSC the player will either output a true NTSC signal or some will convert to PAL-60 (60 fileds per second PAL). As nearly all TV's sold in recent years can handle at least one if not both of these types of signals, NTSC to PAL conversion is reraley required. Try a test encode of a short 23.97fps movie to NTSC (with 3:2pulldown if mpeg-2) and see if it will play, you may be pleasantly surprised!

[IvIark]

Hi, thanks for the reply and info.

In answer to your question, I wouldn't normally do it as I'm quite happy to have NTSC discs, but I have to on some ocassions where for instance, I am putting 2 separate movies onto a single disc, one is PAL and one is NTSC. This was the occurance yesterday.

[bugster]

Hi, thanks for the reply and info.

on some ocassions where for instance, I am putting 2 separate movies onto a single disc, one is PAL and one is NTSC.

OK, makes sense to me!