PAL SVCD using NTSC-Resolution

[One2]

The task:
- fitting 130 min PAL video (Movie "The Rock") on two standart CDRs (700 MB each)
- good picture quality

The tools:
- DVDX V1.6
- LSX Premiere Plugin V1.1

My solution:
- VBR (Max 2600, Average 1350)
- 126 Kb/s Audio

Using a 480x576 pixels resolution at 25 fps (PAL standart) needed too much bitrate to get a picture without artefacts. So why not merge the PAL standart with NTSC! ;-)
Keeping the PAL-Framerate i used NTSC resolution (480x480, 25fps) and what i got was a artefact-free picture using my desired bitrate of 1350.

My Standalone-Player (Centrum DVD) didn´t make any trouble... So what do you think about this absolutly non-standart SVCD? I can only speek for myself: It works perfectly and i have the advantages of both TV-Standarts: less fps (PAL) and a lower resolution (NTSC).

[Pko]

...and also an non standard SVCD that the player you have today plays, but god knows if your future player will...

I think a better solution would be to reduce even more the framerate, to 24, while keeping the resolution as NTSC (480x480), and adding pulldown.

That would make a NTSC-FILM encode that is supported by all players since it is standard MPEG2 framerate and resolution and also the quality should be higher since you are encoding less frames.

And more, the standard framerate of most movies is 24fps, so you are using the original framerate!

In fact, 24fps+pulldown is what most movies use when transferred to NTSC DVD, and when they are transferred to PAL, they accelerate a little bit (1/25, or 4%) the movie (that is the reason many movies are 4% shorter in DVD-PAL then in DVD-NTSC). Going back to 24fps is simply getting nearer to the original.

And all that while keeping the standards, I think is a better solution, perhaps you should try it next time...

Personally, I think that both TMPGEnc 2.52 and CCESP are both better encoders than Ligos' that LSX uses, but that is a personal choice...

[FakerZ]

Good answer. But I don't like the choppy playback the pulldown gives.
What encoder do you use ? In cce there is an option for using half resolution. You obtain a 480*288 picture. Have someone tried this yet ?

[nick ctrl]

if i am not mistaken, i think that 352x576 is a svcd standard ( 1/2 D2 ),
and then you have the lower resolution you are looking for.

i've tried on a tokai 715s, and it works perfect, even with non perm. subs.

[Pko]

Originally posted by FakerZ
Good answer. But I don't like the choppy playback the pulldown gives.
What encoder do you use ? In cce there is an option for using half resolution. You obtain a 480*288 picture. Have someone tried this yet ?

Choppy playback? not in my player nor in my PC using WinDVD, I can assure you... Also, most SVCD movies people encode and post on internet, are in FILM mode, and if properly done, they play OK (think of it, you have the most accurate stream to the original; when NOT using FILM, to get 25 or 29.97 fps instead of 24, you are "making" some information from nowhere...)

All my FILM mode encodings where done with TMPGEnc; I've changed to CCESP recently and not tried yet; I suppose they will play the same...

[FakerZ]

nick : 352*576 may work but... you're wasting space because of this 576 pic heigth ! That's why it would be better to use 480*288, if this is standard. By the way, I tried once to make an SVCD using 480*288, but using this resolution before compressing. I was able to read the svcd (and the pic was great, no blocks, superb) but on a friend's player, it looked like an old b/w movie.
I really wonder what this "half resolution" option in CCE will make. I think I'll make a test wiht it.

[FakerZ]

Pko :

How does pulldown work on the standalone ? It is adding a frame from time to time to obtain the desired playback framerate, right ?

[Pko]

Originally posted by nick ctrl
if i am not mistaken, i think that 352x576 is a svcd standard ( 1/2 D2 ),
and then you have the lower resolution you are looking for.

i've tried on a tokai 715s, and it works perfect, even with non perm. subs.

Well... it is NOT standard, but let say that it is "almost" standard...

352x576 (PAL) and 352x576 (NTSC) are both standard in CVD (i'm not sure of this since I have not read "official" specs, but I have read that somewhere; also, my Shinco SVCD player lights a _"1/2 D1" light when I play a SVCD with that resolution).

That resolutions are also on DVD standard... so if your SVCD player is CVD capable or if your SVCD player is DVD capable (and I think all SVCD players in the world are also CVD or DVD capable or both), the chipset that decompreses the MPEG stream must be capable of decompressing that resolution. So, to not play it well, something in the firmware (perhaps some treatment when demultiplexing in SVCD format) must broke the decompression or something.

I think that this is something that almost all players in the world are capable to play, but if you have one of the few (I *suppose* there are few, I can be wrong) players that does not play it, or if you are determined to strictly stick to the standard, you should not use it.

BTW, using this resolutions have one positive thing... if in the future you want to make a DVD from some of your old SVCDs, since SVCD resolutions (480x480, 480x576) are *NOT* DVD standard, you will need to fool the authoring somehow and have a player that plays the nonstandard DVD or you will need to recompress the stream (losing time and quality, tons of both). If you use 1/2 D1, you simply need to remultiplex as DVD (well, you can have some trouble with GOP lenght and so, but that is a more subtle thing), perhaps converting the audio stream from 44.1 to 48KHz -again losin some time and quality, but less noticeable than the video's-. If you introduce one more non-standard "feature" in your SVCDs, 48KHz audio instead of 44.1, you ONLY need to remultiplex. Most SVCD players that are also SVCD capable can play audio at 48KHz in SVCDs (AFAIK).

Because of all of that, I usually make all my SVCDs at 352x480/576 and with 48KHz audio; they play great in all the players I tried them, and if you are short of bitrate (that happens very often in SVCD), the lower *horizontal* resolution help a little.

Think that, in TV, vertical resolution is usually much more important than horizontal; the ray in the TV's tube *does* 480 lines (well, some of the are done out of the visible part of the screen), so the vertical resolution is *real*; the horizontal is done by an analog conversion, and some player do that better than others, but the "dots" are never as accurately done as in a computer monitor, for example.

[FakerZ]

Interesting, really. I think I'll try it too.

[Pko]

Originally posted by FakerZ
nick : 352*576 may work but... you're wasting space because of this 576 pic heigth ! That's why it would be better to use 480*288, if this is standard. By the way, I tried once to make an SVCD using 480*288, but using this resolution before compressing. I was able to read the svcd (and the pic was great, no blocks, superb) but on a friend's player, it looked like an old b/w movie.
I really wonder what this "half resolution" option in CCE will make. I think I'll make a test wiht it.

No, is usually better not to change the vertical resolution because it is *real*, the ray into the TV tube *really* makes that 480 passes... (in NTSC, 576 in PAL). It is because of that that the SVCD resolution is decreased from DVD resolution only horizontally and not vertically.

In a computer, both X and Y axis are treated the same, so a 480x640 and a 640x480 "looks" the same if you simply turn your head ;-)

But the TV set does not treat both axis the same, quality-wise the vertical axis is MUCH MORE important than the horizontal axis.

That is for "normal" TVs, of course; there are lots of displays out there (for example, plasma TVs, or computer monitors) that does not follow this "principles", but 99% of the people uses "normal", cathode-tube, NTSC, PAL or SECAM TVs...

[Pko]

Originally posted by FakerZ
Pko :

How does pulldown work on the standalone ? It is adding a frame from time to time to obtain the desired playback framerate, right ?

Well, each player can do it as they designer programmed it to do it, but the *correct* way to do it (that I suppose most players use) is MUCH MORE complex than simply inserting som frames... it is called "3:2" pulldown because of each 5 frames, only 2 are truly progressive... basically, they convert to 30fps from 24 (well, it is a little more complicated because it is not 30 nor 24, but 29.97... and 23.976..., I put dots because I think there are more decimals). To do 24 -> 30 conversion, you must output 5 frames from each 4 you have in your input... they divide the 4 frames in 8 fields (each field has the even or the odd lines of the original frame) and then they duplicate some of them to make 10 fields and then mix them in a definite way so you have 5 frames, each one from 2 fields of the original, but only 2 of them have both fields from the same original frame. The process is very well explained in many web pages...

Since the TV displays the movie field by field, not frame by frame (it displays a field, and that takes some time; then it goes to the top line again, that also takes time, and displays the next field, and only after that the next frame is processed... so, you do not have really a 30 frame/s display, but a 60 field/s display). All that field/frame thing and the way the human eye works makes the movie play smoothly to the viewer's perception (the pulldown algorithm does things that way because some smart guy invented the method and the video professionals accepted it as good). This process of FILM to NTSC conversion is also know as "telecine"

I am not expert at that, there are people that knows a lot more about this (try Blight or Neuron2 in avisynth forum; they have done avisynth plugins to the the reverse of pulldown; given an NTSC stream made from a film, they try to reconstruct the original, progressive 24fps stream... since you do not know at what "point" of the algorithm you are, and cut&pasting, postprocessing etc, could change it at any point, the inverse process is really complex)