CCE Low Bitrate problems

[sue denim]

Hi guys!

My Pioneer DV444 has a big problem when the video bitrate
of a SVCD drops below around 300bps. The sound breaks up and the framerate becomes irratic.

I did a test MPEG2 VBR encode using CCE2.62.
I encoded the first few minutes of '2001:A Space Odyssey' which
has at least 2 minutes of black screen with music before the opening credits.
I managed to find some bitrate settings that would keep the lower bitrate around my setting :
ave.1150 min.550 max.2200

So ..... all is well ......... or so I thought!!

So now I encode the whole movie (143 mins) with the same settings and check the finished mpv file with bitrate viewer......... to my horror the lower bitrate has dropped to around 160bps !!!!! ARRRRGGHHHHH

What the Hell is Going On ?????!!!!????

Has it got something to do with some kind of bitrate 'range'?
As in, 'if the encoder decides it needs more bits to keep the picture
quality good but it can't exceed the max value, does it adjust the
min value to recover unused bits'?

Anybody got ANY ideas how to get around this?

So far, I've only found TMPGenc to pad the video rate so as not
to fall below my minimum setting - BUT I WANNA USE CCE !!!!

Thanks everyone,

Sue xxx

[KoalaBear]

Ms. Denim:

Based on your post(s), I'm assuming you're trying to cut a 143-minute title into two discs using a PAL CCIR-601 frame size (720x576 -- right?)

So in other words you're trying to squeeze a DVD-sized picture into VCD bandwidth. I'm afraid that can't be done without sacrificing something. Play time per disc or picture resolution, your choice, but one of them has to be scaled back.

For example, if you were to use 3 CDs at 48 minutes each, you could use VBR settings of 1150/1416/2376 which would look and behave as well as vanilla SVCD, albeit with a larger frame size. If you want to use only 2 CDs, you'll need to drop the resolution -- 352x576 (PAL) is just as good as VHS, and VBR settings of 462/924/2376 would be much more to the Pioneer's liking in that case.

Ultimately, the reason you're having this problem at all is that you're trying to squeeze too big a picture into too small a minimum bitrate. Frankly I'm surprised that CCE doesn't crash altogether; you're literally asking for the impossible, which is why I suspect the Pioneer is balking.

But if you just make a tradeoff, number of discs versus resolution, everyone (you and your disc player) will find a happy medium.

[sue denim]

Hi Koala!
Thanks for the reply

I'll try your suggested bitrate settings tonight - fingers crossed!

What I was actually doing was frameserving a 480x576 from VDub into CCE2.62 with the bitrates I mentioned before ..... still think I'm expecting too much??

At this stage I really couldn't care less about how big the final mpg filesize is ..... so long as it never drops into the 'danger zone'!

Ultimately, the reason you're having this problem at all is that you're trying to squeeze too big a picture into too small a minimum bitrate.

Sorry, but can you do me a huge favour and explain how the minimum bitrate is affected by the picture resolution?
Are you saying that, even when there's a black-screen, you need a certain number of bits to represent a certain video resolution correctly?
And if so, why then did the encode I originally did (at the start of this thread), drop to around 160bps??!!??

At the moment, things are a little fuzzy! Can you help me clear them up?

Cheers mate,
Sue xxx

PS - hey we're all friends here ..... no need for the formality!

[SiCN]

Surprising, how did you get CCE 2.62 to accept the VirtualDub frameserver??

[sue denim]

Put the .vdr holding file VDub output into VFAPI-convertor v1.03b and create a 'fake' holding avi file.

This then goes into any prog. that accepts avi files, like CCE2.62.
NB - some programs don't like the framserve and error-out but most are fine!

OK?

Sue xxx

[KoalaBear]

What I was actually doing was frameserving a 480x576 from VDub into CCE2.62 with the bitrates I mentioned before ..... still think I'm expecting too much??

Not at all. 554 Kb/S should be an effective minimum bitrate for that image size; obviously I spoke to soon. :)

When coding with CCE, it's a good policy to do your first pass as CBR at the average bitrate. This distributes the bits more or less evenly across the entire movie with no severe dips or peaks. Then when you apply one or more VBR passes in addition to that, CCE redistributes the bits according to the constraints imposed by the specified limits.

Sorry, but can you do me a huge favour and explain how the minimum bitrate is affected by the picture resolution? Are you saying that, even when there's a black-screen, you need a certain number of bits to represent a certain video resolution correctly?

Well, yes. And no. :)

Even if you were to encode a pure black screen, the encoder should respect the specified bitrate. If you specify a minumim bitrate of 500 Kb/S, for example, the encoder shouldn't drop significantly below that figure under any circumstances. Whether 500 Kb/S delivers a pleasing picture at a given resolution is a different question, but if you're specifying 500 Kb/S minimum and getting 160 bps, something isn't right.

Can you describe your overall encoding strategy? Maybe we can finger the culprit from that.

[sue denim]

Hi mate!

Thanks for all your input on this pain-in-the-ass problem - much appreciated!

I tried some of your bitrate settings w/ picture resolutions last night ............ nothing doing I'm afraid.

I encoded the same section of '2001:A Space Odyessy' (which has black screen with music before the opening credits).
In both versions of CCE I have (2.62 & 2.50), if I set the minimum bitrate to 500Kbps, the encoded M2V file drops way down to around 160Kbps!!

Check this though ...... ave.1150 min.976 max.2372 res.480x576
Using these settings on the same section of '2001' I got a M2V file which, at the lower end, hovered around the 450Kbps mark!!
If I run this encode again but change the 'quality' slider to 0 (ie. bit alocation is 'complex'), the lower bitrate of the resulting M2V is 300Kbps!!
HOW CAN THIS BE ???

OK - here's my encoding procedure .......

1.) rip the DVD with Smart Ripper (current version)
2.) DVD2AVI 1.76 to create a .d2v project file and .wav audio
3.) write a AVISynth script to load the .d2v file as an mpeg2source (using mpeg2dec.dll) and bicubic resize to 480x576.
4.) load that .avs into VDub
5.) frameserve from VDub to create a .vdr 'holding' file
6.) use VFAPI-convertor v1.03b to convert .vdr to 'fake' .avi
7.) load this .avi file into CCE2.62
8.) encode using 550/1150/2250 -- quality slider to 0 (complex) and noise filter to 32 (max) -- progressive -- zigzag -- linear quantization scale -- lum.0-255 ... er..... that's all I can remember!!

You're thoughts will be VERY welcome.

Laters,

Sue xxx

[kinneera]

When coding with CCE, it's a good policy to do your first pass as CBR at the average bitrate.

Point of clarification here...isn't this what CCE does automatically - when it generates the .vaf file? I thought the only reason to do the CBR pass manually first is if you want to use the advanced VBR settings, which is more in the realm of specialized tweaking for some specific reason.

[Kdiddy]

Sue:

Why dont you just get CCE 2.5, and just load the avs file directly into CCE with Vdub (unless you use special filters)??

There is no differences in the enocding quality tween 2.5 and 2.6 of CCE, but I find 2.5 a we bit more flexible. Also, I think your vfapi usage adds time to your encoding process due to it works only in RGB. So I hope you choose RGB color in both CCE and DVD2AVI in order to eliminate time spent on color conversion.

[wildcatfan]

If I run this encode again but change the 'quality' slider to 0 (ie. bit alocation is 'complex'), the lower bitrate of the resulting M2V is 300Kbps!!
HOW CAN THIS BE ???

That is the problem right there....when you set it to allocate more to the complex areas it is doing exactly that, its giving more bits to the complex areas of the film.... and then there isn't enough bitrate left to keep your specified minimum. try setting it at 25.... maybe even 35 and that should help without to much noticeable loss in detail in the complex scenes....

[Kdiddy]

I actually wouldnt recommend going over 10 with that quality slider. You will pay for it in your complex scenes. I do find that CCE nor really any other encoder stays EXACTLY on the parameters set, so it dipping below the min is unfortunately a fact of life you just have to deal with, for I find that sometimes it even peaks higher than the specified max.... It should using the low bits on scenes that actaully require low bits, which in your case yes, black scenes require very few bits. The reason it dip below your min is more likely that CCE found a complex scene which CCE felt required more bits. CCE then felt that in the low bit scene it could encode with less than the min and maintain scene quality..and thus moving those extra bits to the complex scene which required more to maintain scene quality.

I had a very still scene once I thought wasnt getting the proper bitrate, and thought "maybe if I raised my min, it wil get better". Well failed to realized that while the scene low in motion, it was highly detail, and actually wasnt getting enough bitrate, and I had to up my max.

[sue denim]

Cheers Wild!

I sort of guessed it might be my 'priority' slider setting!

I'll try your suggested settings tonight and see what sort of picture quality I can achieve.

Seeing as I'm encoding for SVCD, do you think I should have the 'Linear Quanization' swiched on or off?

@ KDiddy -- when I started testing it was with CCE2.50. The lower bitrates I got were a lot worse than with CCE2.62 ...... however, given the new info I've gained from you guys, I'll give it another go.
I must admit, I'd much rather use 2.5 because of it's .avs compatibility!

I'll be back when I have the results from my latest tests .......

Cheers,

Sue xxx

[Kdiddy]

Well to add in my personal opinion, using an average bitrate of 1150 is not CCE's strong point. If you are going to be using averages that low, I would go with TMPG. I dont care for CCE less than 1600.

[sue denim]

Yeah, but if I have my average up around 1750Kbps and my max at 2372, no matter where I set the minimum I always get and encoded file with a bottom 'dip' around 160Kbps !!! grrrrrr

Any other suggestions?

Why can't CCE have a 'Pad Minimum Bitrate' option like TMPGenc??!!??

Cheers,

Sue xxx

[KoalaBear]

OK - here's my encoding procedure ...

1.) rip the DVD with Smart Ripper (current version)
2.) DVD2AVI 1.76 to create a .d2v project file and .wav audio
3.) write a AVISynth script to load the .d2v file as an mpeg2source (using mpeg2dec.dll) and bicubic resize to 480x576.

Fair enough.

4.) load that .avs into VDub
5.) frameserve from VDub to create a .vdr 'holding' file
6.) use VFAPI-convertor v1.03b to convert .vdr to 'fake' .avi
7.) load this .avi file into CCE2.62

This part seems like overkill, doesn't it? Why not dump steps 4, 5, 6 and load the AVS directly into CCE 2.5 instead? This would be much faster at any rate.

8.) encode using 550/1150/2250 -- quality slider to 0 (complex) and noise filter to 32 (max) -- progressive -- zigzag -- linear quantization scale -- lum.0-255

I think we might have a whiff of a smoking gun here.

encode using 550/1150/2250 -- unless you're coding audio at 350 Kb/S, you're wasting some of your peak bitrate. CD-quality audio is 224 Kb/S, so 2600 - 224 = 2376.

quality slider to 0 (complex) and noise filter to 32 (max) -- Very not good. The quality slider tunes the global quantization scale to correct for certain kinds of artifacts: Gibbs (haloes) towards the low end, aliasing (off-color blocks) toward the high. I strongly suggest leaving it at the default until you're more experienced. Trust me on this. Also, because your source is DVD, you don't need noise reduction at all. Just deselect that option.

progressive -- zigzag -- These are OK.

linear quantization scale -- lum.0-255 -- These are not.

What "Linear quantization" does is substitute the MPEG-1 quantization matrix for the default MPEG-2. It's kind of like tying one hand behind the encoder's back. Nonlinear quantization is an improvement over MPEG-1, so it's a good idea to make use of it. If you plan to watch the encoded video on TV, use luma 16-235 because bandwidth has to be preserved for "blacker than black" and "whiter than white" signal components. Not doing so may result in a peculiar type of artifact known as a wraparound.

that's all I can remember! -- As I stated earlier, I would recommend doing your first pass as CBR at the average bitrate, then add additional VBR passes to optimize the bit distribution after that. You could use one-pass VBR instead of CBR on your first pass, but considering the problems you're having, you want to start with an even, reliable bit distribution first.

Give these suggestions a try. I think you'll see a substantial improvement in the result.

------------

When coding with CCE, it's a good policy to do your first pass as CBR at the average bitrate.

Point of clarification here...isn't this what CCE does automatically - when it generates the .vaf file? I thought the only reason to do the CBR pass manually first is if you want to use the advanced VBR settings ...

If multi-pass encode is selected and there's no VAF, CCE will indeed generate a working copy of the file in the process, sans audio. You can encode the audio separately later, but I prefer to have it on hand at the conclusion of pass 0 so I can multiplex and view the file and judge the quality prior to further bit-twiddling. It's a matter of taste I guess, but it's a custom that's served me well.

[sue denim]

Hey, that's some great info Koala - thanks a million!

I'll give it one more try with the settings you suggested.

The reason I don't use 2.50 is that I 'seemed' to be able to control the bitrates in 2.62 ...... now I know I can't I'll switch back!

I encoded the whole movie (2001:A Space Odyssey) last night using the new 2-pass VBR in TMPGenc 2.51PLUS and was very impressed at the difference between the old and the new.
Maybe it's my eyes (or my TV!) but I think it compares quite well with CCE at the bitrates I'm encoding at.
Needless to say, I bought a license this morning!! :P

I'll let you know how I get on mate!

Cheers,

Sue xxx

[homerpez]

I don't know if this was even touched on anywhere (I got dizzy reading the posts)! but...

With CCE, I would suggest to you that you can raise the MIN bitrate, to even 700 or 800 in your case, and not have any problems.

TMPGEnc is much worse than CCE as far as dipping low, CCE does seem to have a problem going too high...

If you want to get into CCE's "Safe Zone", raise your MIN to only 200 or so less than your AVG, and do at least 4 passes. CCE is so good at calculating it correctly, you won't have to worry about the end file size (like you would in TMPGEnc).

See, in CCE, you don't have to try to "balance" the MIN, AVG, and HIGH as much... TMPGEnc tends to not make your file the calculated size if you don't "balance" them.

Mine typically are 1000 AVG, 700-800 MIN, 2520 MAX for SVCD's.

[sue denim]

Thanks Homerpez .........

....... will give your advice a shot over the weekend .........

....... gotta go now - lots of testing to be done!!

Cheers,

Sue xxx

[sue denim]

Hi .... I'm back!

Guess what ..? ...... NOTHING WORKS

I tried all you guy's advice about resolutions, bitrates and general settings and I still get an encoded MPEG2 file that drops to around 160Kbps !!!!

I've had it with CCE now, I really have had enough

What I can't understand is that nobody else out there has this 'lower bitrate' problem - 'cos I know many DVD players that f*ck up when the bitrate falls real low ...... grrrrrrr

Guess I'll have to stick with TMPGenc afterall ....... trouble is, it creates such huge file sizes.

Thanks for trying you guys anyhow ......

Sue xxx

[KoalaBear]

Don't give up now, Sue. That would amount to a waste of time for both of us. You've reached a blocking point and I appreciate how frustrating that can be, but that's just the way learning curves work.

I tried all you guy's advice about resolutions, bitrates and general settings and I still get an encoded MPEG2 file that drops to around 160Kbps!

There are only two explanations that can account for this outcome: (a) there's something wrong with the encoder itself, or (b) there's something wrong with the way you're using it.

If the problem is in the encoder, you might want to obtain the CCE binary from another source and reinstall. I know there are patched versions in existence (some people just have to dick with the quantizer matrix even though there's no good reason to do so) but it's entirely feasible that such patching could result in the problem you're having with it.

The procedural modifications and settings suggestions given above were reliable, so there's no reason you shouldn't get good results from using them. I'm assuming you followed them to the letter rather than picking and choosing those you felt most appropriate under the circumstances, yes?

[sue denim]

Yeah mate, I stuck to your suggested settings perfectly first, and then, when I had no joy, tweaked a little to see if I could find a good balance.

I've got 2.50 and 2.62 and I have similar problems on both ...... so I guess I've got to call myself a dumbo and probably too dense to figure this one out (even with all your help!)

I've tried SO many different settings now ..... I've got a whole 10Gb partition full of CCE test encodes!!

Sue xxx

[KoalaBear]

If you were a "dumbo," Ms. Denim, I doubt you'd have made it this far. :)

You're a hard worker, and that will pay you dividends once you're over the hump. If it's any consolation, it takes most people somewhere between 6 and 18 months to accumulate the skills necessary to obtain good results on a reliable basis. After that the world will be your oyster, but you're still in the process of paying your dues and they don't come cheap.

But enough of the pep talk. Let's try to find some answers.

Yeah mate, I stuck to your suggested settings perfectly first, and then, when I had no joy, tweaked a little to see if I could find a good balance.

You did your first pass as CBR at the average bitrate? What were the results at that point, prior to applying VBR? (Incidentally, how are you measuring the bitrate of the encoded video?)

I've got 2.50 and 2.62 and I have similar problems on both

You don't need both. Remove both programs in their entirety, pick one of the two, reinstall it and see if that affects the result. What if one installation is interfering with the other? I would take 2.5 myself (a non-patched version of 2.5) because it supports AVS files directly. All 2.6 gives you is the ability to play with the quantization matrix, which is an absolute no-no. And in the event your version of 2.5 is patched to support "custom" matrices, this could explain the outcome.

[vhelp]

sue,

has anyone even TRIED encoding your movie "2001: a space odyssey"
to see if they get the same results you get???

I would, but I have my own issues with CCE not working on my system.
Ask someone here to encode some scenes that you have problems with
for ya to see if they get the same results!!

I have a curious question to ask ya...
Did you try and encode BELOW your problematic 300bps in TMPG and
burned and played on your DV444, just to see if it give you the same
trouble? ? ?
Just curious. This is something that I would have done - just ta C...
Why don't you give it a go! You may be surprised!

-vhelp

[homerpez]

I'm baffled as to why my "solution" didn't work... on movies I've made, when I set the MIN bitrate to, say, 1000k... I pull up info as it's playing, and by golly it stays at 1000k!

The only time I've ever had bitrate-drop problems (video slows way down, then resynchs) was using TMPGEnc.

As an aside, you ARE using bbMPEG to multiplex, right? SVCD radio button? "0" for mux rate? Just making sure...

I guess if you have these problems, I should not be looking to far into buying a Pioneer DV-343 then, if it has these sorts of problems... I'll just have to replace the bad ROM unit in my Apex.

[kinneera]

I guess if you have these problems, I should not be looking to far into buying a Pioneer DV-343 then, if it has these sorts of problems... I'll just have to replace the bad ROM unit in my Apex.

I think she said she has a DV-444 (older model, correct me if I'm wrong). The DV-343 is an excellent unit that plays just about anything - some of my TMPGEnc VBR encodes have dropped below 200Kbps, no playback problems.

[sue denim]

Hey, thanks guys - you've made some great suggestions there!

You know what? I'm rapidly coming around to your way of thinking Koala regarding the 'double/patched' installations.
BTW - thanks for the pep talk ...... I'm gonna hang-on in there 'till I sort this baby out!!!

I'll de-install all my versions and start again with the 2.50 demo (UNPATCHED!) just to see what bitrates I get.
To answer one of your questions, I use BitRate Viewer to check my encoded MPEGs.

I tried your CBR suggestion ..... but I still get a bitrate of around 160Kbps in the blank-screen sections ..... but, naturally, when there's video content it jumps straight to the CBR setting (in this case my average)

I checked the actual VOB bitrates and they drop to exactly the same minimum as my CCE encoded MPEGs - curious

@vhelp - no, to my knowledge, nobody's tried to encode '2001' to see what results they get.
If I don't set the padding, TMPGenc will also encode MPEGs which fall to the VOB's minimum - I checked.

@homerpez - your confusion as to why it works for you and not for me leads me to a suggestion that Koala maybe right - my double installation and patching may have screwed the matrices in both versions.

Finally, from what I can gather, the DV343 is 'bullet-proof'. I've heard very little that would disuade me from buying one.
I bought my DV444 a little under 3 months ago .......... I've had a few problems but really nothing too serious ...... mainly down to me having to learn how to encode correctly!!

Ah well, back to work I guess .........
Thanks again (we'll beat this mutha yet!)

Sue xxx

[RoopeT]

Can't you just force CCE to increase the bitrate locally on the spot(s) that give too low bitrate? (on CCE advanced bitrate setting, if you don't know what I'm talking about check robshot.com). I haven't tried this yet myself (because it requires some extra work), but it should help.

[sue denim]

Yeah, but it doesn't work for me !!

Thanks for the URL though. It's taught me a little more about what exactly is going on in the .vaf file.

Sue xxx

[RoopeT]

What do you mean by saying it doesn't work for you (CCE crash or do you still get min 160 kbps ever after forcing it locally ta a higher bitrate)

[sue denim]

I still get a min bitrate around 160Kbps.