Quenc settings!

[joho83]

I was backing up my Monster dvd the other day, and it was one of the first times I've used Quenc... I was not at all satisfied with the quality, got quite alot of artifacts... I belive my settings were the wrong ones... Quality is my only concern, if anyone should wonder...

I've noticed that some of the DVD's are interlaced and some are progressive... So I will devide my settings into two parts here:

1. Interlaced:
"Extreme & Slow" settings - check
Gop Size 12
Max B-Frames 2
Force Closed Gop - uncheck
Scene detection - uncheck
MPEG-2 Mux Profile - DVD
Interlaced encoding - check
Top Field First - uncheck
DC precision - 10
Pulldown - uncheck
Auto Max Bitrate - uncheck
Max bitrate - 9400 (use that always)
Process Priority - High
Audio Codec - AC3
Audio Bitrate - 384
Bitrate - Everything fromm 7000-9000 depending on the movie size...
Use VBR, High Quality, Use Trellis and 2 pass encoding all check.

AVS in the DVD-rebuilder have the following settings:
ConvertToYUY2() - check
Audio Dub - check
Filter Editor - uncheck
Deinterlace with DECOMB - uncheck
MPEG2Source - uncheck

2. Progressive:
Use all the same settings but these:
Interlaced encoding - uncheck
And should I here use the function "disable interlaced" and click "apply to all"?

Is this correct or is something wrong? I'm a newbie, so I do need some help... If there is something you would have set differently, please do reply... I would be very thankful :)

And by the way, my avi-script looks like this:
LoadPlugin("D:\Mediaprogrammer\AviSynth 2.5\Plugins\DGDecode.dll")
mpeg2source("D:\D2VAVS\V02.D2V")

Should I add something more into this script or is it correct? I really have no idea, have just read the guide... I cant play the script in Media Player, get some kind of error-message...

I will by the way only be watching the dvd on a regular tv, not on my computer.

[jel]

hi joho83,

i will move this thread to the "Other MPEG1/2 encoder" forum, where hopefully one of the quenc gurus can help you out.

good luck
j

[Mug Funky]

some advice:

1. don't transcode your audio. use the audio that came on the disc (it's a piddling difference between 448 and 384 after all, and the quality loss from transcoding is almost always unacceptable at any bitrate - it's just how lossy audio works).

2. try turning closed GOP on for 2-pass. so far i've only noticed a difference on 1 sample, but it was a marked difference. possibly there's a ratecontrol oddity when open-GOP 2-pass is used. this doesn't seem to affect 1-pass. more testing is needed on this though... keep your original encode and compare them, then report back :)

3. you're using pretty high bitrates, so you can probably get away with 1 pass instead of 2 (and save lots of time).

4. try a high bitrate matrix. one that i use a lot is a standard mpeg matrix with all the numbers divided by 2. this also helps combat undersizing.

5. you don't need extreme and slow at all... same with trellis. trellis seems to work better in mpeg-4, and it's not worth the speed loss. all it does is round up or down depending on what compresses smaller. when you're using a high bitrate the difference is invisible, and often worse.

6. leave a second of black at the end (or just some video you don't care about. there's a small bug in 2-pass ratecontrol that makes the last second
get overcompressed by a fair amount.

generally, QuEnc should work almost perfect with it's default settings - Nic likes it that way.

happy encoding!

[joho83]

Thanks alot Mug Funky, that helped me! Have some questions left though...

1) How do I "turn off" transcoding audio? Can't seem to find that option, the only thing I can do is choose between 64 and 384...

2) Have now checked Force Closed GOP.

3) Should I lower my bitrate or? Because I still want to run 2 passes for best quality... I really have no idea how to set the bitrate, should I have a fix bitrate, or change it depending on the size of the movie? How do I calculate this?

4) Can't seem to find the bitrate matrix either, what does that mean? Only thing I can find in the settings is QBL matrix...

5) Ok, no "e & s" or "trellis".

6) I usually cut the movie right before the scrolling text is showing at the end of the movie, by using vobblanker... But how do I choose to leave a second of black in the Quenc settings? Is that possible, or do you mean when I'm blanking...

Have a few more questions, and then I'll never bother u guys again ;)

7) When the DVD is Interlaced, then I should check "interlaced encoding" right? But not check the "deinterlace with DECOMB" setting in DVD-rebuilder setting or?

8) Is my script okey, or should I add something more?

LoadPlugin("D:\Mediaprogrammer\AviSynth 2.5\Plugins\DGDecode.dll")
mpeg2source("D:\D2VAVS\V02.D2V")

I cant play the script in Media Player, get some kind of error-message...

I will by the way only be watching the dvd on a regular TV, not on my computer. And only be using the Quenc to back-up my DVD-collection.

Very thankful for any replies.

[Mug Funky]

>> 1) How do I "turn off" transcoding audio? Can't seem to find that option, the only thing I can do is choose between 64 and 384...

what i mean is rather than re-encode your audio, just use the ac3 from the DVD and mux it with the video you get from quenc.

>> 2) Have now checked Force Closed GOP.

hehe. not too sure if it even makes a difference... seems to only on very short clips

>> 3) Should I lower my bitrate or? Because I still want to run 2 passes for best quality... I really have no idea how to set the bitrate, should I have a fix bitrate, or change it depending on the size of the movie? How do I calculate this?

you need a little bit of maths for this - bitrate = total space available / movie length.

sounds simple, but you need to fill that in with good numbers, and you must take audio and subs into account. also, subtract a few megs for stream overhead and safety (i find it helps to round the result down to the nearest hundred kbps - you wont miss 30kbps, but it could prove the difference between an oversized encode and a just-right encode).

>> 4) Can't seem to find the bitrate matrix either, what does that mean? Only thing I can find in the settings is QBL matrix...

what i meant was a matrix that uses a high bitrate. search the forum for "CQM". it might help to download a matrix editor, or just use the one in xvid (quenc takes xvid matrices). QLB is a low bitrate matrix. with matrices, lower numbers give higher bitrates and more detail. don't use numbers below 8 though, or you risk b0rking playback on some machines (i'm not sure if it's standard compliant, but it's certainly not advisible). one i like using is a matrix made from the standard mpeg matrix with all numbers divided by 2 (rounded down).

though it seems you're using DVDrebuilder, which implies you're working with low bitrates. QLB may be just what you need in this case...

>>6) I usually cut the movie right before the scrolling text is showing at the end of the movie, by using vobblanker... But how do I choose to leave a second of black in the Quenc settings? Is that possible, or do you mean when I'm blanking...

you can do it in the avisynth script by putting this at the end:

last++blankclip(last).trim(1,25)

change the 25 to 24 or 30 if you're working with NTSC FILM or regular NTSC.

this is just a fail-safe because currently QuEnc's 2-pass ratecontrol messes the last second. it's a trivial bug that will be fixed as soon as nic gets a little time (thanks, nic :))

>> 7) and 8)

script seems okay. it's pretty basic, but fine for backing up DVDs. to get a space saving you can use telecide, but only if your sources are NTSC FILM. anything else and there'll most likely be problems. also, i'm not sure if rebuilder adds pulldown flags after encoding to bump the framerate back up to 29.97 (losslessly of course). if you're using PAL footage, there's no need for telecide, but you may need to use interlaced encoding for DVD extras, as they're almost always interlaced (especially for PAL movies, where extras are often standards-converted instead of encoded directly from a PAL master - this gives the dreaded "field-blend" and requires interlaced encoding).

bottom line: if you can spare the time, take a look at your video before you encode it and suss out whether it's interlaced, telecined, or whatever. if your media player is giving you an error, it might be because you don't have a YV12 codec. install ffdshow and set it to decode uncompressed (in both directshow mode and vfw mode) and you'll be fine. also consider virtualdub for previewing, as it's the bomb :)

k. hope i didn't say too much to digest... if you're unsure about stuff, just search or browse the forum. but careful - there's so much info here it can be overwhelming.

[TomBrooklyn]

bottom line: if you can spare the time, take a look at your video before you encode it and suss out whether it's interlaced, telecined, or whatever.
How does one tell if a video is interlaced, teleclined or whatever?

[Revgen]

How does one tell if a video is interlaced, teleclined or whatever?

Go to www.100fps.com to see some samples.