xVCD or SVCD for the best ratio quality/space

[royfra]

What sould I use to have the best possible quality to fit a 90min movie on one CD ? xVCD (MPEG1) or SVCD (MPEG2) ? And wich encoder : TMPenc or CCE ? what's setting of bitrate ?

thanks

[Vejita-sama]

At the same bitrate and resolution MPEG1 looks the same as MPEG2, so xVCD vs SVCD (if both at 480x480 video=2520 & audio=224) will be look the same. However, you can encode MPEG1 faster than MPEG2 so many people choose to make xVCDs over SVCDs.

As for space, the size of the encoded MPEG file is 100% dependant on the bitrate. The size of the source, the resolution of the source, the resolution of he encoded MPEG and MPEG1 vs MPEG2 has NO effect on size. Just bitrate and runtime.

Use one of the bitrate calculators to determine the necessary bitrate (look under the Tools section to the left) for a 90min movie. I suggest lowering the audio from 224 -> 128kbit/s to give more bitrate to the video.

CCE does much better and much faster MPEG2 encodes than TMPGenc, for MPEG1 TMPGenc is slightly better (IMHO). If you're working with a DVD rip then I'd do 3pass VBR (min=300, max=2520, ave=calculator) in CCE. If it's a DivX source, then CBR (or 2pass VBR) is more than good enough.

[loudanddeep]

someone made a comment that MPG2 encoding offers better compression ratios than mpg1, and then made the implication that if you encode a mpg1 VCD file, with MPG2 you will get a smaller file.

I do not know if this is true, or I misunderstood the poster.

thanks...

dp

[Vejita-sama]

There's some confusion but I can't say from where. Compression wise MPEG1 and MPEG2 are the same. The reason MPEG2 is 'better' than MPEG1 is because MPEG2 supports more features: interlaced source, multiple audio tracks, multiple angles, selectable subtitles, etc. But if you're not making use of any of these features it doesn't matter.

Ok, now I'm going to take a guess about file size. There's a common misunderstandin about VBR (variable bitrate) vs. CBR (constant bitrate) encoding. Some people believe that VBR makes smaller files than CBR, but this really isn't the case (there is one possible exception). I'm going to assume that you are using TMPGenc to encode.

CBR - you set a bitrate and it used to encode the whole movie. However, during faster motion scences it's possible that your bitrate will be to low, resulting in 'poor' video quaility. Similar during low motion scences you're sort of 'wasting' bitrate. The solution...

VBR - The program will raise the bitrate during high motion scences, and lower it during low motion parts. In TMPGenc there are two ways to do this:

CQ_VBR - constant quaility VBR: TMPGenc tries to keep the quaility of the encode constant through the whole movie. The problem is it doesn't know how many low/high motions parts are in the movie. Plus the settings (from 0-100) make no real sense As a result it's impossible to predict the size of your resulting MPEG. However, it often works out that the file will be smaller than if you choose CBR (often but not always, again can't really predict).

2pass VBR - this is 'true VBR' as it were. TMPGenc makes to passes. First a CBR pass, then a VBR pass to allocate the bitrate. You set the a min bitrate, max bitrate and ave bitrate. While encoding the bitrate will not drop below your min setting, or raise above your max setting. And the program will raise/lower the bitrate so that the average works out to the ave setting you choose. This means that you can predict the final size of the MPEG file (basically ave bitrate x runtime, just like CBR). But because of the VBR pass you get a better quaility encode.

So why not use 2pass VBR all the time. Well first it doubles the encode time (ie. makes 2pass or two encodes). If you have a poor video source (eg. Divx) well GIGO. For DVD rip source it makes a big difference. In fact for DVD rips I normally use CCE w/ 3pass VBR.

Sorry that's so long, but I hope it helps. Any questions

[royfra]

thank you Vejita-sam for your great explanation ! :P

[ApacheWraith]

So what would be the best one for a VHS capture? Aren't we, in effect, enhancing, digitizing, a movie capturing it from VHS and making say an Svcd? Wouldn't the best quality settings make the vhs better?

Thanks.

Wraith

[compupc1]

Although sometimes you can apply filters to help the picture, remember the saying Garbage in, Garbage out. Like you can't convert a 20 megabyte DivX of a 45 minute TV show to a DVD stream and expect a DVD quality picture.

[ballfam]

I know this is off topic slightly, but I'm not getting the quality I'm looking for out of TmpegEnc two pass VBR. Even when I split a 90 min movie to two XVCDs and run at an average rate of 2181 to burn to an 80 min CD using 3000 max bitrate and 0 min bitrate, I get some blokiness on the higher action scenes, I've tried at 704x480 and 480x480, and now I'm running again at 352x240, the theory being that there are less lines to encode, so the bitrate can do a better job on what's left. I realy don't want to push lower than 480x480 if I can help it, since I'm playing through an s-video output...anyway, to the point... Vejita-sama, I noticed that you said you used CCE 3-pass to encode, is this significantly better TmpegEnc, and where canI get a copy? Is there a demo I can use to run multi-pass VBR, or do I need to pay big-bucks to get hold of this software?
Anyone else have any ideas on how I can get a better quality output, or, mnore acurately, avoid the blokiness on some scenes. I started with a DVD (Rush Hour2) ripped with CladMdec.

[siliconsoul]

im having the same problem.... im trying to backup American Pie 2 at a decent quality.... on 2 80 min cds... if i have to go 3 cds i will but i would perfer not too.... i downloaded a 2 cd svcd 80 min of a movie and it was alsome compared to what im getting with 2 pass vbr in tmpgenc!

what am i doing wrong? what seetings should i use? do i need to deinterpolate? yes im a newbie and totaly lost with dvd ripping to svcd... but i can not get good settings at all and the templates are not that great...

i can convert divx to svcd like a champ but i do not want it in divx first then reencode to svcd! HELP!

if you can point me to a good guide or a forum thread that will help out!

[ApacheWraith]

I guess it depends on the source. I did a dvd rip the other night. I encoded a small clip from it using kwag's template, the picture was really awesome, I tweaked it a little because there were some very slight motion blocks, which I expected. I wanted to see how good I could get the picture, I set the bitrate to 3000 and they were gone, now the picture looked really good, but no better when I set the bitrate to 8000. I set it to 8000 just to see, and it looked the same. Also, to confirm something kwag mentioned about mpg1 versus mpg 2 I encooded 2 samples 1 mpg1 and the other mpg2. At the same bitrate (3000 max) the mpg1 far outdid the mpg2 quality. Now mind you the only thing I changed was the mpg format, from XVCD to I guess SVCD or XSVCD whatever (don't want this to turn into a format argument) the mpg2 encode was unwatchable, it gave me a headache. The mpg1 was perfect for me. As I said FOR ME. In my opinion the quality was excellent, the onlky real drawback was the 2 cds, but then again who cares. kwag is gettting about 16MB per minute with his template, I tested it, I am getting somewhere around 20, I doubt I'll get much more than 45 minutes on a cd (80min), but I don't care the quality outweighs the 2 disk problem.

L8TR,

Wraith

[siliconsoul]

i could care less if i hvae to goto 3 80 min disks at this point... svcd with 3000 max bitrate on 2 pass vbr with average at 2000 does not look that good... im going to burn multiple samples today and test on my apex at my house the 3 disc changer one and then take it to my gf house which is a apex 1000.
i hope i can find a good ratio....

is there a way to put those burned svcd disc in an see what settings they used or is that impossible?

can you give me a link to the template you are using...

[ApacheWraith]

SILICONSOUL,

I tried that too, to see the settings after the burn. Couldn't do it. I would contact kwag and see if he can send you his template, it looks pretty good when you up the BR slightly, then it really looks good, I haven't tried this with a VHS capture yet though.


L8TR,

Wraith

[siliconsoul]

br?
brightness?

[ApacheWraith]

BR= BITRATE

[siliconsoul]

wow now you can tell im a newbie to encoding video!
hehe

:-)

[ballfam]

where can I get kwag's template? Is it a template for TmpegEnc?