XSVCD some Questions

[AgNa]

Ok I done some SVCD (like 40) before but now I put my hands on a XSVCD and Quality is amazing :D, my question is how the fuck did this guy to put 66 minutes into one 74 min disc with that quality?? I got his spec, but I would like to get some more explanations about how to make a xSVCD with that Quality, and how to calculate the bitrate and so on...., I know XSVCD is jus a non standart SVCD but I just don`t get how to get such quality :confused: :confused:

The movie is LOTR 1 extended edition
- encoded with TMPGEnc - CQ56-60 - Highest Quality
- resolution 672x304 (Cinemascope 2.35:1) - Letterbox 720x576 (PAL)
- Codec: MPEG-2, min. 200kbps, max. 3600kbps, GOP 1-9-1-1

- Audio 1: German, MP2, Surround-Downmix, 44KHz, 192kbps
- Audio 2: Englisch, MP2, Surround-Downmix, 44KHz, 160kbps

Maybe I`m worng but high resolution doesn`t need more bitrate to keep it looking good?? but If I do the bitrate cal. in any calculator it gaves me like 1500avg bitrate on a resolution of 480x480, I don`t need to say thats not good and even worst if I aplly it to a 720x480 resolution. But how he make such great quality 66 minutes into 1 cd???

I can post a pic if it`s necesary (don`t post it now couse it`s gonna bee a little big)

PS: I hope this is the right forum
:rolleyes:

[haroldw]

I'll take a shot at this. First off you have most of the critical settings:

CQ 56-60
min. 200kbps, max. 3600kbps, GOP 1-9-1-1
720 x 576 (Pal) so it should be 25fps
it is a "letterboxed" video the actual area/res used by the video is 672x304
motion search precision highest quality

The reasons why I think he was able to get 66 minutes at "amazing" quality are.

1. The area that is actually being used by the video, because of the letterboxing is approximately 1/2 of the area of the entire TV screen.

2. Perhaps there are not many fast-action, or other sequences that require a high bitrate to maintain quality, so much of the video may be using a video bitrate closer to the 200kbps end.

3. Pal uses 25fps, vice NTSC using 29.97fps, so there is less frames to expend the bitrate on, "unless" you are comparing it to the NTSC film rate of 24fps.

4. Lastly highest quality motion search precision does help some.

I would suggest you try it out yourself. It sounds like you are on the NTSC standard, so create an XSVCD 720 x 480 res, NTSC film framerate or use the pulldown, CQ 58, min 200kbps, max 3600 kbps and a GOP of 1-9-1-1, highest quality motion search precision, on a letterboxed video with minimal action sequences. I suspect you could get similar results.

Yes, you are correct in your thinking that "in general" (and this mainly applies to constant bitrate) 1500 kbps used at a 480 x 480 resolution should give a better quality image than 1500 kbps used at 720 x 480 resolution. This is because the bitrate is spread over a larger area with the 720 x 480 resolution.

You have to remember, though that the CQ method is not constant bitrate, it's constant quality, so when, to maintain the quality level it doesn't need much bitrate, than it doesn't use much bitrate and when it needs a high bitrate to maintain the quality, only then does it use the high bitrate.

[2COOL]

Originally posted by AgNa
Ok I done some SVCD (like 40) before but now I put my hands on a XSVCD and Quality is amazing :D, my question is how the f**k did this guy to put 66 minutes into one 74 min disc with that quality??

Funny thing. I just did a PM to Kwag here in Doom9 about 30 minutes ago. Kwag is the big man at KVCD.net. His site specializes on VCDs and SVCDs and more. It's no surprise that they can put 180 minutes on a CDR and with great quality. You should check his site if your interested in XVCDs/XSVCDs. Just my 2 cents.

2C:cool::cool:L

[AgNa]

Hey thanx for the responses, I tried without succes to reconvert the file to NTSC (using the same settings) I got a 1.5 gb file instead the 750 of the original size, I guess due to the black borders wich I can`t remove couse I`m adding the subs in there, but this Q don`t belong here so I`m gona ask in the righ forum ;)