xvcd or svcd at lower bitrate??

[kjmacke]

All I want to know is there any quality difference in an xvcd at 1800 birate and a svcd at 1800 birate??

[adam]

I assume you mean an xvcd at svcd resoltuions? Otherwise the answer is that it depends...

Mpeg1 and mpeg2 are theoretically identical at the same settings. You should not be able to see any noticable difference between xvcd and svcd if you use the same settings.

[vcd4me]

HEY ADAM,

I was actually wondering the same thing.
Do you mind explaining this a little more in detail.
It might help both myself and KJMACKE.

Well say you had a 1800 bitrate like he KJMACKE how would you go about doing either xvcd or svcd?
Would you use standard templates just change the bit rate?

I've always just made a standard 1150bitrate for vcd no matter what the bitrate I got when downloadeding. I have never really created anything else but was wondering if I should do something diffrent to get better quality seeing as my PIONEER should play anything according to the compatibility chart.

THANKS in ADVANCE
VCD4ME

[adam]

xvcd has no real parameters. The term simpy implies that you are using mpeg1 but that your settings do not comform to the vcd standard.

To compare xvcd and svcd, like kjmacke did, you have to assume that all settings are equal, namely bitrate and resolution. So the in this case the only difference between the two is that xvcd uses mpeg1 and svcd uses mpeg2 and at the same settings these two should be identical.

So if you wanted to recreate kjmacke's example than you would simply load the ntsc svcd template and set the bitrate to 1800kbits and encode your svcd. Then take that ntsc svcd template and load the unlock template. Change mpeg2 to mpeg1 and encode and you'll have your xvcd and both should look about the same.

If you have a Pioneer that supports svcd, and your source is high quality like a dvd, than you should try encoding in svcd. You will definitely see a major quality improvement. You can try xvcd if you want (simply load the vcd template and raise the bitrate as high as your willing to go. Maybe use vbr and a bitrate calculator to exactly fill the cdr) but if your dvd player supports svcd I don't see any reason to use xvcd, it can only result in compatibility problems.

[kjmacke]

Thanks for the post Adam. As for vcd4me you up the bitrate for better quailty then it becomes an xvcd.

[vcd4me]

Alright let me see if I got this correct

Let's stick with this file- 1800 bitrate

If I make it to vcd using the bitrate of 1800 instead of 1150.This now becomes xvcd and the quality would be better than standard vcd. but not as good as a svcd using 1800 bitrate?

If this is true then I think I been losing quality on some of the movies I've downloaded

Now if I had a downloaded dvd rip in say 1199 bitrate I couldn't up the bitrate to 1800 and get better quality could I?

.THANKS IN ADVANCE
VCD4ME

[adam]

vcd4me your not taking resolution into account.

If you take standard vcd settings and raise the bitrate to 1.8mbits well you have a resolution of 352x240 @1.8mbits, whereas a svcd at 1.8mbits will have a resolution of 480x480. Here quality becomes debatable...Higher resolution means sharper picture but less bits per pixel so which one is higher quality is really a matter of opinion.

Sticking with the 1800kbits example. If you raised resolution to 480x480 and raised the bitrate to 1800kbits then yes it would look better than a vcd, assuming your source was high quality. However this xvcd should look identical to a svcd encoded at 1800kbits. Like I said at the same settings mpeg1 and mpeg2 are identical.

I think your confusing the purpose of xvcd and svcd here vcd4me. Your final product can only look as good as your source. If you download a file at 1199kbits and increase the bitrate to 1800kbits it won't look any better, in fact it will probably look worse due to the extra transcoding.

[supercrew]

Don't forget on important difference between xvcd & svcd, if you use
svcd with mpeg2 you can choose VBR encoding. If you use CCE and set the avg: 1800kbs max: 2472kbs min: 900kbs, you will end up with a file the same size and the CBR xvcd at 1800kbs but high motion sequences will be allocated more bits than a low motion scene.

Therefore you get the higher resolution in the same filesize with no noticable distortion of the picture.

You can really tell the difference if you have a high resolution source such as a DVD.

MPEG2 also supports interlaced video, which means if you are only going to watch your video on you television. You don't have to de-interlace all that home video you have shot.

Believe me, if you have some good quality DV that you want to save create a SVCD. If it is plain VHS quality either one is fine, in fact I prefer XVCD for that because CCE will encode CBR MPEG1 about 3 (three) times faster that VBR MPEG2 with multiple passes.

Hope this helps....

Supercrew

[adam]

Yes but xvcd can use vbr also...the whole point of xvcd is that you can do whatever you want.

When I said xvcd and svcd will look the same with identical settings I meant just that...whether you use vbr or cbr as long as you use it on both than the output quality should be the same.

[vcd4me]

ADAM you said

If you take standard vcd settings and raise the bitrate to 1.8mbits well you have a resolution of 352x240 @1.8mbits, whereas a svcd at 1.8mbits will have a resolution of 480x480. Here quality becomes

Ok now I'm more confused
What is the resolution for a tv in the USA?

Then you said

If you download a file at 1199kbits and increase the bitrate to 1800kbits it won't look any better, in fact it will probably look worse due to the extra transcoding.

That's what I thought but wasn't sure

So should use the full 1800 or what ever I have to get the best quality instead of using standard 1150vcd?

Thanks in advance
VCD4ME
ALSO SORRY ABOUT THE HIJACKED THREAD

[adam]

"What is the resolution for a tv in the USA? "

USA tvs (ntsc tv's) have no set resolution. They display picture at 640x480 but any ntsc compliant resolution can properly be stretched to fit this.

the ntsc resolution of vcd is 352x240. For svcd its 480x480 and for dvd its 720x480.

An xvcd can literally be anything as long as its mpeg1. Ntsc svcds will always be 480x480 so if you want to compare this to an xvcd than you would need to use the same resolution, otherwise the quality differences become subjective.

"So should use the full 1800 or what ever I have to get the best quality instead of using standard 1150vcd?"

More bitrate will always result in more quality as long as your source is high quality enough to take advantage of it. If your dvd player supports it then yes it would probably be a good idea to abandon the vcd standard and simply increase the bitrate until you run out of room on your cdrs. You can do this by either creating an xvcd or by making a svcd which natively supports higher bitrates, as well as vbr encoding.

[vcd4me]

THANK YOU ADAM

You know what they say you should learn something new everyday.
You have helped me to learn today.I thought the display picture and resolution were one in the same but now I know they are not.

Thanks again
VCD4ME

[Craig Tucker]

Give kwag's tmpgenc template a try. I hav'nt used it myself yet, as the pc I use for capture got a bit scorched (waiting for new components), but I have read many good things about it on this forum. Increasing bitrate and resolution is going to reduce the amount of time you can get on one cdr. This XVCD template is supposed to give a quality that rivals SVCD and allows up to 120 minutes on an 80 min cdr.

Like I said I hav'nt actually tried it, but as soon as my pc is repaired I will give it a shot.

Craig

[adam]

I tried it, its far from svcd quality. Its actually sub par to vcd. Squeezing that much content onto such a small space is not a good idea.

[Craig Tucker]

In your opinion Adam, what is the best template that has been devised, and is available on this site. My Pioneer 636 wont play SVCD's, so it has to be an XVCD. What I would like is something that will give quality that will rival SVCD and will store at least an hour of video on an 80 min cdr.

Cheers.

Craig

[adam]

Honestly I think templates are pointless for distributing settings. All they are good for is saving time.

If you want a high qualty xvcd you need to preserve the original framerate of 23.976fps, if possible. That grants you an extra %20 bitrate.

You may want to consider using a resolution of 352x480. That saves you another%25-30 bitrate over a conventional svcd.

Always crop and add borders and you can go ahead and crop an extra 10 pixels or so from the picture since this will not be seen anyway due to overscanning.

You can use light noise reduction if you want. If your using a high quality source like dvd your never going to be able to preserve all the quality of the original picture so why try? Noise reduction prevents you from wasting bitrate on artifacts and detail that is going to be lost anyway. Again I have to stress that you should only use light noise reduction. Even a little too much and the picture becomes too soft.

Other than that the rest of the settings are pretty much obvious. If your dvd player can accept vbr mpg then use a bitrate calculator and fit however much of your movie onto each disk that you want and of course always encode with multipass vbr instead of CQ or any other form of 1-pass vbr. Otherwise just use cbr and fill up each cdr. Just exeriment to see what is an acceptable balance of quality and compression. Personally I never put more than 1hr on an 80 min cdr regardless of what I'm making.

Sorry I'm sure this wasn't the answer you wanted but I don't feel anyone should just download a template and use it to encode everything with. Personally I think the best templates available are the ones that come with TMPGenc.

[ubaddala]

Adam,
Nice post. However, I need some clarification/suggestion on my situation:
The source for me is NTSC Hi8 home video. I usually capture at 352x480 in VirtualDub (no compression/filters) and encode with TMPGnc as xVCD (352x240, 29.97 fps). I use a bitrate of 1500 kbps for video and 224Khz for Audio, CBR. I get a decent picture (almost as good as source) and I could fit around 63 min. video on a CDR. The basic idea is to archive my Hi8 and send these CDs to my family where they use PAL VCD players. In this situation I am just wondering will there be any gains by encoding the xVCD @23.97 fps ? If so, can you please list the exact steps in carrying out the above ?

Also, is true that for a MPEG-1 file there is no NTSC or PAL demarkation ? If yes, then why have 2 separate versions of PAL and NTSC ? Last time when I sent my ULead made VCD (NTSC standard) people were able to watch the VCD in PAL players !

When I encoded the VCD/xVCD to 23.97 fps and played back the video using PowerDVD, I had a lot of jerks, which is the fps conflict.

- Uday

[adam]

Performing an inverse telecine and converting your material from 29.97fps to 23.976fps frees up %20 more bitrate. Your source isn't particuarly high quailty and you say you are just about achieving equal quality in encodes. If this is the case you may not even want to bother with IVTC'ing. If, however, you think raising your bitrate by %20 would help the quality then IVTC is definitely a viable option.

The simplest way to IVTC is probably just to use TMPGenc. Load your source and in the advanced tab double click on the inverse telecine filter. Set it to 24fps and tell it to do it while encoding and otherewise I always just use the default settings. Encode to 23.976fps your done. Not all matial can be IVTC'ed. If you see interlacing (little white lines usually during movement) or jerky movement than your out of luck, you'll have to keep it at 29.97fps.

You can also use avisynth and IVTC filters to do the IVTC. If you go this route I would download and install DVD2SVCD. It installs avisynth properly. You can then use an avs script generator like gnot to create the script. Then you can use this script to frameserve to your encoder, and again just encode to 23.976fps.

Pal and ntsc are definitely not interchangable. The major reason for the different parameters is due to the different power currents that countries use. Here in America we use 60Hz and in many pal countries they use 50Hz. Ntsc tv's will not properly display a pal signal. You get black and white picture, scrolling, or both. Most pal tvs are actually multiscan which means they can play pal or ntsc, just like a computer monitor can. Thats why your family members were able to play your ntsc videos. If it had been the other way around it wouldn't have worked.

Back to the framerate issue...If your source is 29.97fps you cannot simply convert to 23.976fps. Film originates at 24fps and is telecined to 29.97fps by splitting the frames into fields and then repeating some of those fields. So you see frames are actually being added. In order to reverse this process you must remove the exact frames (actually fields.) that were added. This is exactly what inverse telecine does.

[Craig Tucker]

Adam
Perhaps I should of mentioned, but I am in the uk so use pal 25fps

Craig

[adam]

Ok well then just ignore framerate issues. Using pal your pretty well off, as far as framerate is concerned.

[gordo2020]

Firstly, if I've got high quality video such as DVD, would I gain significant quality encoding at double VCD resolution (704x480)?

Secondly, if I am encoding at double VCD resolution is this going to affect the amount of video I can put onto a CDR or will I still be free to increase the bitrate to the same level as I would for 352x240?

Thanks

[adam]

Well first off, just in case you didn't know, 704x480 for video complies with neither the vcd nor the svcd standard. The only compliant ntsc resolutions are 352x240 for vcd and 480x480 for svcd, though 352x480 will still be compatible on all svcd hardware players.

Ok, you have realize the subjectivity of quality, in particular when comparing resolution vs bitrate. The higher the resolution the sharper your picture, but as you increase resolution you increase the total number of pixels you have. This means that as resolution increases you must also increase your bitrate just to maintain the same level of quality. So a file encoded at 704x480 @1MB per sec will be sharper than a file encoded at 352x240 @1MB per sec, however the lower resolution mpg will have significantly more bits per pixel and to the casual viewer, will actually appear to be much higher quality. Basically it comes down to whether you prefer sharpness and clarity over less artifacts and an overall cleaner picture, but this is something that you have to decide for yourself.

Bitrate and resolution are independant from each other. Regardless of what resolution you use you can encode the video at any bitrate, and vice versa. However, as I already explained, bitrate and resolution do go hand in hand so you need to find a logical middleground.

The best starting point I can suggest is the one that has been suggested by the creators of mpeg1 and mpeg2. 352x480 @2MBits per sec is considered one of mpg's sweet points. If you use a higher resolution than you "should" use a roughly portionally larger bitrate, and vice versa. Again, this is all highly subjective. You really need to run some tests and see what looks best to you, however I really don't recommend using 704x480 as there are other more compliant resolutions. Also 704x480 would require a great deal of bitrate to maintain quality, something which is in short support at vcd and svcd bitrates.

Personally, at bitrates between 1MB and 3MB I think the best ntsc resolutions to use are 352x240, 352x480 and 480x480.