SVCD video max bitrate?

[cardboardguard]

if you are doing a SVCD with 1 audio track (at 224 kbps) what's the max bitrate you can use on the video?
I just encoded a movie using MIN: 1145, MAX: 2496, AVG: 2450, and once i got it into bbmpeg, i just got DTS and PTS underflows.

Is there a formula like AVG BITRATE + AUDIO BITRATE !> 2600 or something?

Because if I encode it at 2300 it works fine

[WarpEnterprises]

The underflows are due to VBV-settings and muxrate.
Use VBV=224 in TMPGenc and muxrate=6972 in bbmpeg.

[cardboardguard]

i'm using bbmpeg, and i am using that muxrate.. still get the DTS/PTS underflows

[Vapor]

The standard denotes:

Max 2524 kbit/sec MPEG-2 (if the audio is in 224 kbit/s), audio + video bitrate max bitrate is 2748 kbit/s. (Courtesy of www.vcdhelp.com).

I use 128 audio and video 2620 max - no problems on any DVD player.

[WarpEnterprises]

What encoder do you use?
What VBV settings did you make?

[cardboardguard]

I'm using CCE 2.5
as stupid as this going to sound, i'm not sure what you mean by VBV.
Don't get me wrong, i've encoded a handful of SVCDs. i just not sure what it is.

Varial Bitrate Video?


audio + video bitrate max bitrate is 2748 kbit/s.
I use 128 audio and video 2620 max - no problems on any DVD player.


the problems lie within bbMPEG, and not in players. I forced film in DVD2AVI, made vapi AVI, and served as AVS. ENcoded in CCE, pulledown, used vob2audio to grab the audio, BeSweet to encode it to mp2, and bbmpeg bitched about DTS/PTS in muxing (where my muxrate is 6972)

i'm puzzzled

[Kb_cruncher]

cce does not always conform to the min/max bitrate you set.it will go higher if it thinks it needs to i.e with high motion movies.too smart for its own good.
you can either reencode and use a lower max bitrate or increase the muxrate in bbmpeg(this will also increase the muxing over head).if its just a few underflows(under 1000)it should'nt really matter but too many underflows and the movie will playback skippy on your dvd player.

[mb1]

Set your muxrate to 0 (means automatic) in bbMPEG !

VBV means video buffering verifier.

vcdhelp.com is completely wrong with its svcd maxima of 2.748 kbps. I told them already with detailed explanations, they confirmed but didn't change anything.
atm vcdhelp.com/forum is down so I can't link to the thread where I have mentioned that.

[Vapor]

> What encoder do you use?
> What VBV settings did you make?

Video: vob > d2v > avisynth > CCE
Audio: vob > graphedit > wav > ssrc downsample > toolame mp2

As far as other settings I use 3 pass VBR, min bitrate 850, max bitrate 2620 and average bitrate of whatever I need to fit the number of minutes I need on the CD (usually 1650 to 2000 for a 16:9 movie unless it's only short).

I used to use Tmpg for video with the standard VBV settings provided in their template - since using CCE I see no place to set VBV so ignored it (maybe my ignorance here but I can't see the setting).

I use Tmpg for muxing and chopping but it seems to lose SVCD compliance in the process so I mux the video and audio first, then chop it up then run the parts through the simple muxer again selecting MPEG2 SVCD - nero and other packages accept them fine then and the 10 odd DVD players I play them on seem to have no probs. The only major prob I find with some DVD players is due to the speed I burn the CD's at - they get jerky if burned over 4 speed.

Could Tmpg be setting the VBV correctly as part of it's muxing process maybe?

I did wonder about the figure on vcdhelp so looked up the official standard on http://www.licensing.philips.com/ which to be honest does not make anything clearer. It basically states a video bitrate of 2.6 megabits per second and audio upto 384 kilobits per second but not whether each affects the other.

I make way for a more specific response from a more aged user :)

I can only summise that seeing as most DVD players decode both mpeg video and mpeg audio using the same processor (that I can see) that in some way the video and audio bitrates do affect each other. On this I decided on the setting I use to keep my SVCD's within standard.

All of the above are only my humble opinions based on information I've gathered and tests done to see what works best for me.

[cardboardguard]

to mb1: thanks for the tip, i'll try that!

to vapor:
i refuse to use TMPG as i've noticed CCE's video quality is quite a bit better. along with that, for lower avg bitrate movies, more than 2 passes is requied ,and TMPG can't offer that.

but beyond that vapor, i don't know if you were trying to help or if you were just stating what you were doing and thinking i should do the same. i do use graphedit often to decode audio, but find that on multiple audio track DVD's it seems to fail me.

[mb1]

Could Tmpg be setting the VBV correctly as part of it's muxing process maybe?
No. Normally you should set vbv during encoding with tmpeg to the allowed max of 224 KB (Tmpeg uses 112 KB standard which is too low).
CCE always uses 224 KB for mpeg2 and 40 KB for mpeg1.

The very old Tmpeg 0.12 beta (no a or so) had a vbv optimizer as part of its mpeg tools. It was no longer present in higher versions due to a little bug.

bbMPEG has vbv settings in its muxer but that doesn't change wrong settings during encoding.

To change a (wrong) vbv in an already encoded stream process as follows:
- use vbv optimizer from Tmpeg 0.12 beta
- demux stream (because vbv optimizer writes two headers instead of one)
- remux with bbMPEG (which deletes the wrong header)


SVCD overall max bitrate is dependant from 2x CD-ROM speed:
2 x 75 x 2.324 x 8 = 2.788.800 bps or 2.788,8 kbps
But muxing overhead, subtitles, all audio and video is in that value.
A recommendable value for video + audio is 2.718 kbps whereas video only has to be max 2.600 kbps.
These values had to be lowered of you want to additionally mux subtitles with iAuthor muxer.
Exact values can be seen with FitCD which also needs muxer and authoring info. All muxers make different muxing overheads.


I can't remember how often I did write those lines in different forums (and people always do it wrong because almost all guides give wrong informations).

[Vapor]

cardboard: Just letting you know what I do really - just in case it helps :)

mb1: thanks for the accurate info.

[WarpEnterprises]

@mb1: Can go something wrong when using the VBV = 0==automatic setting in TMPG? I searched (in dvd-svcd-forum too) but didn't find an answer.