Can DVD Shrink do PAL > NTSC Conversions?

[fateman]

I doubt this is possible, but worth a try...

[wmansir]

Nope, and I don't think any other transcoder could either. The problem is you have to change the framerate/framesize, in addition to adjusting the audio and reencoding it to AC3. First, Transcoders can't change the video in that way, it has to be re-encoded. Second, to redo the audio they would have to include a AC3 encoder, which means a significant royalty payment to Dolby per copy.

[jstorey1967]

i think it can if you go into the settings you can choose what region you want it form 1 - 9 or multi

[wmansir]

That just changes your regional code, which is a control mechanism, it does not change the technical specs that make a disc NTSC or PAL. Some players can play both PAL and NTSC (and covert the output to whatever type of TV is connected), and changing the regional code is all that is required to let it play a DVD from another region. But some can only play one type, regardless of the regional code.

[TheXung]

I don't think any transcoders have such ability but really the only real difficulty is probably cropping the frames because I think you might have to do something different for the edge macroblocks, for the motion vectors and whatnot, they can't just be removed. I don't know enough about bitstream specs but there's probably a very clever hack that could get around this. If such a movie had letterboxing bars on the top and bottom, then it could be done. If you're one of those that needs their faces to be exactly the right proportions, then I'm sorry, there's just no way of doing a veritical resize by transcoding.

Other than that, PAL movies are for the most part the original 24 fps filming just played at 25 fps. The transcoder would have to put telecine flags in. The audio should need no conversion if PAL DVDs have them at 48 khz, just a matter of remuxing.

[wmansir]

Originally posted by TheXung
Other than that, PAL movies are for the most part the original 24 fps filming just played at 25 fps. The transcoder would have to put telecine flags in. The audio should need no conversion if PAL DVDs have them at 48 khz, just a matter of remuxing.

Yes, but if you change the framerate of the video, without changing the number of frames, you change the length (in time) of the video. But the Audio stays the same length, so you loose sync. You have to time compress/stretch the audio to match the new video length when converting.

[TheXung]

Originally posted by wmansir
Yes, but if you change the framerate of the video, without changing the number of frames, you change the length (in time) of the video. But the Audio stays the same length, so you loose sync. You have to time compress/stretch the audio to match the new video length when converting.

I forgot about that. Someone once told me that time stretching/shrinking audio wasn't really complicated; a matter of changing the length of periodic functions. If AC3 or DTS was a transform based codec, such an operation should be possible within a transcoder. Though this is all theory talk, it would take an unbelievable amount of skills to do this. To date, I haven't even heard of a working audio transcoder.