System Bitrate for SVCD?

[Amit]

What should be the SYSTEM MUXING bitrate value for SVCD's?

I am asking this 'coz everytime, I try to put my MPG file generated by D2S in Roxio Videowave 5.1, I get the warning that the SYSTEM MUXING rate is not as per specification.

Thanks
-Amit

[UltimateDBZ]

Never heard of such a thing, though maybe it's just given a different title in D2S.

Does this error prevent you from using the file in Videowave, or is it just a notification? In case of the latter, it's not really a big deal...

[Amit]

@UltimateDBZ
First of all, sorry for the TYPO. The name of the program is Roxio VideoPack 5 . I am currently using the latest version 5.1. Here's what I get when I add a bbMPEG_muxed.mpg file into the project:

SYSTEM
Mux Rate : 303880 bits/sec
Type : MPEG 2
Video Standard : NTSC
Packet Length : 2324 bytes
Duration : 56:38:04
VIDEO
Frames/Sec : 29.97
Resolution : 480*480
Bitrate : 2530000 bits/sec
Video Codec : MPEG 2
AUDIO
Sample Rate : 44100 samples/sec
Bits per sample : 16
Channel : 2
Bitrate : 224000 bits/sec
Audio Codec : MPEG 1 L2

The first two line in SYSTEM i.e. Mux Rate is shown in RED and I get the error message that its not as per SVCD spec. And YES I can continue but VideoPack than does the SPLITING and MUXING again to fix the problem. I don't want VideoPack to do the muxing again as it spoils the file sometimes causing sync problems. Also, since it doesn't support subtitles the subtitles are lost.

Any idea how to fix the SYSTEM muxing rate. It's part of the MPEG spec.

Thanks
-Amit

[UltimateDBZ]

I have a feeling this is because of the program itself, since I've never heard of such an issue before. Why are you using the MPG with this application in the first place? What do you want to do with it? Have you tried another application that could do the same thing?

[Amit]

This is a very good tool for authoring VCD/SVCD/DVD. It has very good GUI for menu creation etc. I want to use this tool if possible.

FYI: If you open TMPG encoder, after you cancel the Wizard (if it starts), you will see at the bottom right of the screen "STREAM TYPE". It has the following settings:

Video Only
Audio Only
SYSTEM(Video Only)
SYSTEM (Audio Only)
SYSTEM (Video+Audio)

So, if you ahevn't heard of SYSTEM muxing rate, this will give you an idea that its part of the MPEG 2 Specification.

Using Roxio VideoPack make me beleive that the MPEG file generated by D2S is not SVCD complaint. I can be worng if this tool reports wrong information. Is there any other tool you know that can tell me whether the information reported by Roxio VideoPack is correct or not. If its a problem with VideoPack 5, I can report to SUPPORT Desk for further help.

Thanks for taking interest in this post. I really appreciate it.

-Amit

[UltimateDBZ]

D2S doesn't make 100% SVCD compliant MP2s, in fact it is capable of making MP2s far from the spec. It's up to the user to make it as close as possible. Perhaps a setting you changed caused this. D2S has never been made to stick directly to the SVCD spec, mainly because most DVD players could care less about the specifics (like 48/44.1khz audio, for example).

[Amit]

Can you or someone else be kind enough to tell me what the settin should be in D2S to make a 100% SVCD spec compliany SVCD?

Thanks
-Amit

[Justinus]

It's weird! Look at the mux rate under System. It's only 303880 bps. Isn't it should be 2754000 bps (2530000 + 224000). Did you set anything wrong? :confused:

[markrb]

Roxio Software and DVD2SVCD have never gotten along.
Most of the SVCD community feels that Roxio stuff is
rather poorly written and recomend using something else.
EZ-CDcreator is on the official do not use list.
I would imagine this is another product of that same
issue.
If you want a menu system software that is known to work try TSCV.

I am only reporting what I have read here and other places. I have not used their software myself.

Mark

[Amit]

@Justinus
That's the problem. The reported mux rate is more than the required. I basically use default settings under bitrate and for audio I always use 224 at 44.1 Khz.

Is there any freeware tool that can report correct information of the muxed file? I can use that tool to figure out whether Roxio VideoPack is reporting wrong or there's some problem in my D2S settings.

@markrb
I don't disagree with you that most of the roxio stuff is crap. If you go to Roxio VideoPack forum, there moderator said that SVCD spec says the MPEG should be 2.6 Mbps and should be CBR. But I know that SVCD spec is based on MPEG2 and says that it can VBR with maximum avg muxed rate of VIDEO only not excedding 2600kbps and the audio should not exceed 224 kbps at 44.1 Khz.

In my D2S settings I use 2530kbps max avg, min 300kbps and avg 2230. Nasically everything set to default. I was just wondering if there's any tool that can report mpeg file information like system/video/audio mux rate and stuff.

Thanks
-Amit

[Justinus]

@Amit
There's several softwares I've found that they can do this job ;)

Bitrate Viewer (http://www.tecoltd.com/bitratev.htm) - program and elementary video stream.
EncSpot (http://www.guerillasoft.com/EncSpot2/) - elementary audio stream.
MPEGID (http://www.lilapple.com/products/mpegid.htm) - both video & audio (program & elementary) stream.
MProbe (http://www.interra.tv/product.html) (never used)
bbTools (http://members.cox.net/beyeler/bbmpeg.html) (never used) - can find it from the main software page at Doom9.org (http://www.doom9.org)

Good luck! :)

[Amit]

@Justinus
Thanks for information about different tools.

@markrb
I checked the MUX RATE of the MPEG file with the following softwares:

Roxio VideoPack 5.1
MPEGID
bbMPEG

They all report the SYSTEM MUXING rate is 2948.80 kbps when the Video Bitrate is 2530 kbps and Audio Bitrate is 224 kpbs.

When D2S opens the bbMPEG by calling RunbbMPEG, if you maximize the window you can see that bbMPEG is muxing the Video and Audio at a rate higher than the Video+Audio

Does anyone knows why is it happening and what settings do I need to set so that the System Muxing rate is as per SVCD spec?

DVD2SVCD is a great program, I was wondering if we can make SVCD as per spec it will be great.

Thanks for your help,
-Amit

[Justinus]

@Amit
I doubt that whether you made the right setting, especially bbMPEG setting. I used to use DVD2SVCD for several times and there's no problem about multiplexing. Anyway, if you can't really get along with this software, why don't you try to multiplex manually? If you check that to keep all files, you'd already have m2v and mp2 to multiplex. And let's see the result ;) Maybe bbMPEG is the good start. If you can do it manually, there might be something wrong with the current setting in DVD2SVCD.

[Jason28]

@Amit
I would have to guess that the subtitles that you are using is pushing the bitrate too high. AFAIK bitrate = video+audio+subtitles.

[markrb]

There could be one other issue here as well. Software encoders tend to stray outside the bitrates given. There was a discussion some time ago about this and the conclusion came out to be that both CCE and TMPG violated their bitrate settings numerous times. Sometimes by hundreds of Kbits, but only for a fraction of a second. Most players just ignore it as an error and continue, but some very few did have issues. Mostly the problems caused issues at the low end when the bitrate dropped below the setpoint.

Maybe this could be having an affect and in that case no real solution was ever found that I remember.

Mark

[Justinus]

I used CCE 2.64 with SVCD option and it still went beyond the max bitrate anyway.

So, the solution is "what do you want?". If you want to play with PC, any bitrate is fine. However, if you want to play with DVD player whether it fully or partially (when it doesn't say it support SVCD) support SVCD, you rather find out your own setting that can play well with your own DVD player. And the setting may a bit varied depending on the movies you're working on ;)

[Amit]

So, what I interpret is that CCE does deviate from its designated bitrate causing the SYSTEM BITRATE (Video+Audio+subtitle) to go higher than the SVCD spec.

Question 1:
What's the impact of adding subtitles on BITRATE? How much bitrate is being added, for CVD style subtitle?

Question 2:
What's the structure of an MPEG2 file? I bet there must a header for the whole file and most softwares just check that instead of reading the whole mpeg file to figure out the SVCD compliance.

If there is such thing then we can use some multiplexer that writes the right SYSTEM BITRATE settings in the MAIN FILE HEADER. I can be totally wrong as I have no idea what I am talking about here. I am just making an assumption.

Could someone shed some light here?

Thanks
-Amit

[Justinus]

Question 1:
What's the impact of adding subtitles on BITRATE? How much bitrate is being added, for CVD style subtitle?
AFAIK it increases a bit of the mux bitrate. If you want to find out how many bitrate in total, use FitCD (http://shh.dvdboard.de).

[markrb]

Give this a try and see what happens. It may not be the best solution, but it's something to try.

Drop the Max Bitrate from the default of 2530 to about 2200 and the Max Avg to about 2000. See if that allows you to use the Roxio software and if so keep raising the bitrate until you get an error. Then just shave 50 points off all the numbers for a safe zone and use that as default.
Just do it on a test clip you know is fairly complicated so you know you are pushing the bitrate.

Mark