1pass ABR with TMPGEnc ?

[Episodio1]

Hi! Id like to encode a movie with 1 pass ABR (from AVI to DVD format), but I only find in TMPGEnc:

"Automatic VBR" and "Constant Quality", which none of them lets me choose the "average bitrate" (only a quality percentage).

So... if I'd want to encode 1pass ABR @ 4000 Kbps should I choose:

max bitrate: 8000
and CQ = 50 %

or is there another way to make 1pass ABR?

Thanks.

[Mug Funky]

1-pass by nature isn't all that predictible. one thing you can do is use one of those "autoQ" type programs, or figure it out manually.

that is, find a shortish (1000 frame?) chunk of your movie which you consider to be representative of the action/detail level of the entire feature.

then encode it at a guessed Q level. find the average bitrate of it, then do a little maths on it to figure out what Q level you should have used to get the bitrate you want.

one thing - "quality %" isn't a linear thing, so it'll likely take you a couple of goes, or a REALLY good guess to get the bitrate you want.

[stephanV]

With all that guessing and trying you might as well do a two pass...

[Mug Funky]

hehe... on a slow enough computer it's actually quicker this way :) but only just.

[Boulder]

CQ mode produces better quality than 2-pass in TMPGEnc. It's a bitch to predict and encode, but there are tools that can help you, for example CQMatic + CalcuMatic. The CQ curve isn't linear which makes prediction very hard.

With CCE you can use tylo's CCEFront, and there's also some program for HC I think.

[Episodio1]

Thanks. I didnt want to do 2pass because Im adding hardsubs to the video (with directshow Vobsub). And vobsub doesnt work very well with 2-passes (subs dont appear for a few minutes)


New question then... i tried WinAVI (winavi.com) and the video created matches the DVD size with 1 pass. Ive been checking the video and the bitrate is variable (with the average bitrate I wished). ¬_¬

I checked a few scenes fading to black and the bitrate used for that scenes was 1000 Kbps, and in fast scenes was 9800 Kbps, so WinAVI got some decent 1pass-ABR algorithm. Which free (or open source) software could do that?

[Boulder]

Even if you see bitrates from min to max, it doesn't mean that you have a good distribution of bits. The encoder doesn't know what lies ahead so it may spend too many bits before a high-motion scene which will then look terrible. Any really useful 1-pass mode doesn't have a fixed average bitrate which the encoder would have to keep in mind all the time.

Why don't you try adding the hardsubs in an Avisynth script? There's VSFilter which will do just that.

[Episodio1]

Ive configured vobsub to show the subs as I wish (font type, size, colors, position) but the config isn't saved at all. He shows the subs always the same every time I run it. :(

[Boulder]

You can edit the .idx file in Notepad.