Gspot Specs Related Questions.

[scott274]

Please take a look at this Gspot specs..
http://i91.photobucket.com/albums/k292/abs724/Screencaps/RushHour26-9-2008-101706PM.jpg

I wanted to know what is the meaning of the box labelled "Container" on the top left side. Especially "Sys Bitrate: 1411 kb/s VBR". This specs is of a DAT file on a VCD (working on my vcdplayer) I had created in Nero. Doesn't a DAT have to be CBR to be VCD compliant. I would actually like you to observe the specs a little and tell me if they are VCD standard or not.

[jagabo]

Container refers to the way the audio and video are organized within the file. There are many different standards for doing this like AVI, WMV, MPG1 DAT streams, MPEG transport streams, MPEG program streams, MKV, etc.

You have a DAT file. The total bitrate (audio, video, and overhead) is 1411 kbps. Note that GSpot isn't completely accurate when it reports video bitrates. So the 1119 kbps may really be 1150. Your VCD appears to be within spec.

Variable bitrates are not allowed in the VCD spec. The actual video bitrate doesn't have to be 1150 CBR, it can be less. But then the video stream will then have to be padded with filler to make the total 1150. So it doesn't really make sense to use less than 1150.

In reality very few modern players will have problems with an out of spec VCD unless it's way off.

[scott274]

Container refers to the way the audio and video are organized within the file. There are many different standards for doing this like AVI, WMV, MPG1 DAT streams, MPEG transport streams, MPEG program streams, MKV, etc.

You have a DAT file. The total bitrate (audio, video, and overhead) is 1411 kbps. Note that GSpot isn't completely accurate when it reports video bitrates. So the 1119 kbps may really be 1150. Your VCD appears to be within spec.

Variable bitrates are not allowed in the VCD spec. The actual video bitrate doesn't have to be 1150 CBR, it can be less. But then the video stream will then have to be padded with filler to make the total 1150. So it doesn't really make sense to use less than 1150.

In reality very few modern players will have problems with an out of spec VCD unless it's way off.

I am a bit confused here, Gspot says that the total bitrate is 1411 kbps VBR and you also said that variable bitrates are not allowed in VCD specs. So how can my VCD be within it's standard spec. What should really be the total bitrate of a standard VCD and should it be CBR or VBR.

And i just checked the same DAT file in MediaInfo..
http://i91.photobucket.com/albums/k292/abs724/Screencaps/RushHourMediainfo7-25-2008-93021AM.jpg

Gspot says 1119 kbps and Mediainfo says 1100 kbps which are both far away from 1150 which is what that DAT file may really have. Any way to determine what is the exact (or approximate) bitrate of that VCD file and also weather it is VBR or CBR.

[manono]

Come on, use some common sense. That MediaInfo pic to which you linked says Bit Rate Mode: Constant. Therefore it used CBR encoding. If BitrateViewer can open it, it should say the same thing. It's been years since I've even seen a VCD, so I can't test anything out.

GSpot says 1119 and MediaInfo says 1100., but jagabo already said apps such as that aren't all that accurate. If DGIndex can open it, run the Preview all the way through and when it finishes it'll have an accurate reading (I think).

The 1411 figure is video bitrate plus audio bitrate plus muxing overhead - everything all together. If it's VBR, then maybe the muxing overhead varies. I don't know and don't really see how it matters.

[scott274]

So by MediaInfo specs, my video bitrate is CBR (magnitude unknown), audio bitrate is CBR (224 kbps) and muxing overhead bitrate is VBR (max,min,avg values unknown). Hence the total bitrate is stated as 1411 kbps VBR. Does this fall within VCD standard spec. I mean the muxing overhead and total bitrate being VBR. Or does everything has to be CBR in VCDs.

DGIndex specs is as follow..
http://i91.photobucket.com/albums/k292/abs724/Screencaps/RushHourDGIndex.jpg
Although I still don't understand what is my video CBR and what those three bitrate values stated in the specs are.

[jagabo]

Note that CBR isn't really CBR. The size of each frame varies because the MPEG encoder can't make frames that are exactly a certain size (46 kbits in the case of PAL VCD). But the bitrate constraints are much narrower than with VBR. So there is some tolerance built into the VCD spec. You're going to have to find the White Book spec to find out exactly what the limits are.

[scott274]

Didn't find any news on a standard VCD total bitrate, muxing overhead, VBR-CBR etc on google & wikipedia. Was hoping for some quick answer instead of having to go through the long write-ups, but members here know so little about VCDs now and unfortunately this is the biggest video help forums on net.

Anyways my motive for all this was that I was a bit suspicious that this perticular VCD was not completely VCD standard and still it played flawlessly, in very good quality on my VCD player (something that has happened only 2-3 times so far and i don't remember how). so I was trying to gather as much info on this VCD as possible and then try to make my other VCDs exactly like this one.

Specs for other similar VCDs I have in Gspot (although its probably not of much use now that i know Gspot & MediaInfo don't give accurate reports)..
http://i91.photobucket.com/albums/k292/abs724/Screencaps/Bluesteak6-9-2008-95625PM.jpg
http://i91.photobucket.com/albums/k292/abs724/Screencaps/Godzilla6-9-2008-93337PM.jpg

[jagabo]

I've never been able to find any or the Rainbow Books online. You'll probably have to purchase a White Book if you need it. I seem to recall it costs a few hundred bucks.

[vcd4ever]

What should really be the total bitrate of a standard VCD

The maximum combined bitrate (video+audio) that is allowed for mpeg track's is 1376000 bits/s, but I strongly recommend that you don't use anything higher than 1374000 bits/s.

and should it be CBR or VBR.

I don't know for sure if you are allowed to use VBR, but a properly encoded MPEG1 with VBR is totally accepted by the Philips Videocd Toolkit.

vcd4ever.

[davexnet]

Don't forget a few years back, Tmpgenc 2.5 and the KVCD templates.
Quite popular until DVD burners caught on. Used CQ (vbr) mode. Worked well for getting
a 2 hour movie on a 700 MB CD. Played just fine in my set top player.