Best way to change frame rates...

[boathouse]

Please can someone advise me...

I'd like to convert a 30fps mpeg file to 25fps, since I want to record the Mpeg to a VCR (I understand UK VCR's will only record at 25fps)

I'd like to change the frame rate without having to re-encode the file, since this must reduce quality.

If it was an .avi file I know I could use VirtualDub which allows you to do a stream copy and change the frame rate without recompressing.

Does anyone know how I can achieve this with an mpeg file?

Thanks

[banjazzer]

If you have an NTSC VCD I suggest you first try copying direct to VCR by playing thru a DVD player. This should not be a problem. IMO you will not gain anything by recoding first to PAL. This will result in a drop in quality, and I cannot see it serves any useful purpose.

[t0nito]

Yes it will be a problem unless his dvd player has a built in standards converter because european dvd players can play ntsc but it will send ntsc video to the tv, which isn't much of problem in europe because newer tv's can display ntsc but PAL vcrs will not record ntsc unless (like I mentioned) the dvd player is playing ntsc content and outputing a pal video signal. Hence the need for the standards converter. Another way is if you have a dxr3 or a hollywood + card you can play the ntsc 30 fps mpg an output in pal and hooking up the card to your vcr. There will be a slight jitter because in every 6 frames it will drop 1 because of the
30fps -> 25fps internal conversion. Or you may really have to reencode to PAL 25fps and most important don't forget to resize to PAL resolution e.g 480x480 to 480x576

[banjazzer]

Well, I've copied NTSC source material onto a PAL VCR and played through PAL TV with no problem. So, first off, I would try this and see how it works out. If there are problems then we can take it from there. 8)

[boathouse]

Thanks for your replies...

My DVD player happily converts the NTSC mpeg to a format called PAL-60 (which I presume is PAL at 30fps) which my TV will display with no problem. However my VCR will only record the standard PAL-50. I think this is a limitation that applies to most UK VCR's.

If I was dealing with a DivX file there would be no problem - just do a stream copy in VirtualDub and change the frame rate with no re-encoding.

I wonder why we can't do the same with an mpeg?

I'll keep searching for a solution...

[t0nito]

You can change the frame rate with restream (look in the tools section) but changing frame rate from 30 fps to 25 fps will also change the speed and it will slow down quite a lot! Also you must resize to the correct resolution or else you vcr will have problems in recording anyway that's the main reason why the image is unstable. I've also (just to test) tried recording NTSC in a PAL vcr the results were a black and white wobbly and very unstable playback.

As for the DVD thing I'm sorry but yes banjazzer is right. Most dvd players have a PAL NTSC output option my mustek v520 dvd player has it and I forgot.

BUT. There still is a little jitter and the aspect ratio isnt't very correct (I can live with that) Like banjazzer said your vcr should record with out problems.

I guess the dvd player is the best option unless you can afford a very good NTSC->PAL standards converter which gives better results (correct aspect ratio and no jitter)