Ntsc 2 Pal

[Little_John]

Is there an easy way to convert mpg's that are 29.97fps to 25fps without getting a jerky picture? or can I keep 29.97fps but change the resoloution to eg. 720x576, if so how do I do it, I've tried Tmpeg but it tells me there is an invalid audio sample for that resolution.

The reason I need to do this is because my TV won't let me play NTSC it's in black & white :(

I have looked everywhere I can think of for this answer and I might have already by passed it, but I've read that many now my head is spinning :confused:

Thanks in advance

[Xesdeeni]

Give my conversion script a try: http://forum.doom9.org/showthread.php?s=&threadid=35387

Xesdeeni

[Little_John]

Thanks Xesdeeni I will check it out, be prepered for some questions :D

[Arky]

Originally posted by Little_John
...or can I keep 29.97fps but change the resoloution to eg. 720x576
The reason I need to do this is because my TV won't let me play NTSC it's in black & white :(


the reason it plays back in black and white is to do with the framerate, not the framesize.

NTSC TVs operate at 60hz, whereas PAL TVs operate at 50hz.

NTSC footage = 29.97fps, wheras PAL footage = 25fps.

50hz/25fps, 60hz/29.97fps.

You do the maths!

I admit i don't know the precise reason for the colour carrier signal not being processed properly, but nevertheless, I'm sure, from the above, thatyou get the picture (no pun intended) as to why the two systems are incompatible, and that you can see why simply changint the framesize will not help matters.

I don't know about Xesdeeni's script, but I can tell you that the only decent (this is very much a relative term when it comes to PAL/NTSC conversions) conversion I've ever seen with software has been with the use of Canopus ProCoder. Easy2bCheesy has some experience with such conversions, and in a professional setting.

there are several other software methods but I have yet to see one stack up against ProCoder. Even then, ProCoder doesn't do a 100% perfect job. The closest thing to perfection in PAL/NTSC conversion is when using hardware solutions costing hundreds of thousands of dollars, I'm afraid!

Also see this thread (which, to be honest, you would have easily found if you'd searched for "NTSC conversion", and gone through the list of results:

http://forum.doom9.org/showthread.php?s=&threadid=39629&highlight=NTSC+conversion+twixtor


Arky ;o)

[Little_John]

Thanks Arky, Like I said I've searched and looked at that many different posts I may have just missed it, I will take a look but it looks like that the best way is for me to get a new TV that can hadle NTSC my current TV does but only through scart and the Sony DAV-S300 DVD player I have doesn't have a scart socket :(

What I carn't understand is that I got a movie the other day and it was 480x480 (so that would be NTSC?) but it was 25fps? I converted it to 720x576 and it was perfect? :confused:

[Xesdeeni]

the reason it plays back in black and white is to do with the framerate, not the framesize.The frame rate actually is not the reason for seeing black and white when viewing one standard on a device intended for the other. If a TV has problems with the frame rate, you will see a rolling picture.

For convenience in our context (digital video processing), we typically refer to NTSC and PAL as if that defines the number of lines and field rate alone. But there is much more to these specifications that we usually can ignore, because the other details have to do with the actual analog signal itself. Worse still, there are variations on NTSC, PAL, and SECAM within those other details.

One of the details that varies is the transmission bandwidth used for each channel as it is sent over-the-air. Once the signal is received and demodulated down to a composite signal, this detail isn't really important (except when discussing lines of resolution).

At the composite level, the detail that applies to the issue here is the color burst (or modulation frequency). For compatibility with black and white broadcasts, color was added on top of the already-in-place b&w signals. This involved a scheme that added color information by modulating the information onto the original b&w signal. NTSC, PAL, and SECAM all used different methods to accomplish this modulation. But in all cases, they needed a reference frequency for the modulation.

NTSC normally uses ~3.58MHz. PAL typically uses ~4.43MHz. This frequency is used by the TV to decode the color information. It should be clear now that if a TV is looking for one color modulation frequency, but the color is modulated at the other frequency, the TV won't see anything useful. That's why you see no color, and in fact probably some interference in the b&w part of the image, due to the modulation itself, which is not only missed by the TV, but not filtered out as it should be.

To add to the confusion, there are some situations where the ~4.43MHz modulation is used on video with NTSC timings, and vice-versa (SECAM is used rarely except during the actual transmission/reception). These are often used in standards conversion devices, especially VCRs capable of playing back both NTSC and PAL tapes. They rely on the TV being able to handle both timings, but they adjust the color modulation. E.g. a PAL TV may have the ability to display an "NTSC-4.43" signal.

Xesdeeni

[Arky]

Fair enough, you know more of the technicalities, so I stand corrected. I am actually happy that you have cleared this up for me. I had always been under the impression it was framerate related (and certainly not framesize related, but I have never denied that I did not understand the deeper underlying mechanics of the black and white issue. Well now I know! :D

My apologies to Little_John for any partially unsuitable advice ;)


Arky ;o)

[Xesdeeni]

Hey, we all start in the same place. :)

BTW, I've run into this issue a couple of times here and on VCDHelp.com. The "dual standard" VCRs modify the color frequency without modifying the timing, expecting the TV to handle it (it seems most PAL TVs do handle 525/60 timing, while most NTSC TVs would not handle 625/50).

But when the question becomes why a capture card set for neither PAL nor NTSC works correctly, it can take some digging to figure out where things are going wrong.

Xesdeeni

[Kilyan]

Hi!
I am very newbie to avisynth scripts, and do not really understand it,...yet!
So my problem is the following, there is a ntsc dvd from film which m2v parameters are as follow:
Stream type: MPEG-2 MP@ML VBR
Resolution: 720*480
Aspect ratio: 16:9 Generic
Framerate: 29.97
Nom. bitrate: 8000000 Bit/Sec
VBV buffer size: 112
Constrained param. flag: No
Chroma format: 4:2:0
DCT precision: 8
Pic. structure: Frame
Field topfirst: No
DCT type: Frame
Quantscale: Nonlinear
Scan type: ZigZag
Frame type: Progressive
Scene change detection: NOT FOUND
Variable GOP pattern: NOT FOUND
Notes:
GOP: IBBPBBPBBPBB


And I want to convert it to pal progressive dvd, with getting the best picture quality possible, with the smoothest motions too :)
I generally use dvd2avi project in the simple avs script to frameserve to cce, and encode 5 pass vbr.
Time consuming script is not a problem, I want to get the best result possible.
Thanks in advance guys!

[auenf]

in that particular one, that should be ripped at 24fps (FILM) and sped up by 4% for PAL

Enf...

[Xesdeeni]

in that particular one, that should be ripped at 24fps (FILM) and sped up by 4% for PALExactly. You could convert it using my script, but the quality won't be as high as doing what auenf suggests.

The trick is being sure to properly reclaim the 23.976fps from the DVD. Some DVDs are recorded at a 23.976 progressive Fps and provide some special bits that indicate to the player how to do the 3:2 pulldown (a.k.a. telecine) to convert it to 29.97 interlaced Fps. Others are recorded at 23.976 interlaced Fps (I don't know why they do this, the bit efficiency is worse with twice as many half-height fields, so the quality will suffer). Still others are actually recorded with the 3:2 pulldown already in place at the 29.97 interlaced Fps, which means 20% of the bits are wasted re-encoding a field that has already been encoded (I REALLY don't know why they do this).

You'll have to determine which type your DVD is in order to reverse it back to 23.976 progressive Fps. Eventually my web page at http://www.geocities.com/Xesdeeni2001/StandardsConversion/index.html will have step-by-step instructions for this process. But I haven't gotten to this yet.

After you've reclaimed the 23.976 progressive Fps, you speed it up to 25 progressive Fps and scale. Then you can encode the video. You'll also have to speed up the audio by the same 4%. TMPGEnc and AVISynth can do most of this if you will be using TMPGEnc as your encoder and want MPEG audio (which is OK for PAL DVDs, but is not guaranteed to work with NTSC DVDs). The above page shows how to do this for VCD, but a similar approach will work for DVD. For AC3 audio, BeSweet is your best approach.

Xesdeeni

[Kilyan]

Thanks for the replies first.


You'll have to determine which type your DVD is in order to reverse it back to 23.976 progressive Fps.
Yes but how to determine this?
And if it is possible, how to do it? with which program, script?

Thrd: Suppose I have demuxed the dvd m2v stream to the harddisk. I just simply load it to dvd2avi and force film? And save the project.
The avs script will be then? (without audio)

I know I know, I am sorry but I have to see the scripts or the way of the process to understand.

Thanks

[mj0012]

Little_john, before you go and buy a new tv you might want to give this a try:
http://www.lik-sang.com/info.php?category=121&products_id=1467&

I haven't tried it myself, but since it's only $3.49 I think it might be worth trying a SCART converter before you run out and get a new tv. Hope this helps.

[Little_John]

Thanks mj I've already got one and it doesn't make a difference :(