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Maybe I'll start by posting my current command line and avs script: The Avs script: Code:
Mpeg2Source("c:\xxxxx.d2v") Code:
mencoder -of mpeg -ovc lavc -lavcopts vcodec=mpeg2video: The way I see it the tricky part is: Code:
:mbd=0:vbitrate=3000:vrc_maxrate=8000:vrc_minrate=300: From what I understood so far these are for min & MAX & average bitrate. I have been using these since the days I saw russiansexpat using mencoder in Linux. Then there are keyint=15 for max GOP size and vrc_buf_size=1835 for vbv buffer size, right? Then I have vqmin=2 and vqmax=24 for quantizer settings. I understand how these work, but since we're already using min, MAX & avg bitrate do we need these? Last one that I know is vmax_b_frames=2 for 2 b frames like IBBPBBPBBP. All the others I don't understand how they work (lack of good manual/linux manpages always disapointed me a bit) and don't know what they are doing there. More what would you change in my command line to seek for 2 movie KDVD. Last but not least where do I get more or less quality? This baby is way different in settings when comparing with CCE/tmpg... Quote:
Only use the makeAVIS that comes with it to make a fake avi for mencoder. Hope you can give me some help with the above issue. Cheers |
Hay guys,
I've got an :idea: ... can we all agree upon a "standard" in the command line params "layout". So that when we are working out issues w/ a given param string(s) we can knew exactly where to look for it, when we're all dealing with params. Here's an example. Lets all keep things w/in a "group", and those that think a given param or set of params belong in a "group", lets all agree to keep them together, especially if they work w/ relation to other params, or "group"'s of params. . . Then, we can include the new agree upon "standard" inside a Sticky post :!: But, if you all think it's not necessary, then by all means, just ignore my idea :lol: and 8) In the mean time, I'll start the first part, and you can include/add in yours. Later, I'll add this feature inside my GUI as a guage :roll: Then, in my GUI, I'll "sectionalize" the items, for easy minipulations w/in the GUI :!: (which I hope to share with you all here and elsewheres soon) Quote:
keyint is set to 18, because, if I understood, this is for GOP. But, I thought it was for KEYFRAMES, as in divX and AVI's :grrr: Also, if we can agree upon exacly, which param string does "exactly" what, we can add that into our Sticky. A glossary. I know there is an .HTML doc, but it's confusing, and it has left all of us to discover what all these cryptic param string/options/subgroups are for ourselves. And, being that we are all working together (I use that loosely) we may as well work as a consortium and in the process, create a "standard" glossary of commands/params or whatever you want to call it :screwy: Think about it :roll: -vhelp |
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But a parameter like this has a reason to exist, right: Quote:
A middle-term between filesize and quality once you discover that this was the problem will be using b_qfactor=1.0 and playing with vb_qoffset between 0 and 1.25 (default value). This will assure a fixed quantizer increase over P-frames, not a multiplied one like when using b-qfactor > 1. Remember that Bquant=Pquant * b_qfactor +vb_qoffset. Bilu |
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Nice explanation. Now at work. I'll try tomorrow. Lots of tests to do tomorrow. Maybe my wife will leave me.... :? |
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But they make you loose quality in high action (explosions,etc.) and anime movies and they're not recommended in this case. But as I mentioned on my previous post, playing a bit more with vb_qoffset and less with b_qfactor can improve a lot on this field. Quote:
Bilu |
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Every guy doing MPEG-4 anime encodes right now disables B-frames completely because it damages the edges. So the fact that B-frames get info from the next frame may not necessarily garantee better frame quality. Usually it does get better quality, but high action and anime are exceptions. But as said before, B-frames are better compressed precisely because they have information of both the previous and the next frames, so probably a lot of info becomes redundant and hence discarded. But when forcing a B-frame to be more compressed than a P-frame and you're doing high action or anime you probably won't get pleased with the results. IMHO B-frame compression factor (relative to P or I frames) should be dynamic, changing as much as the previous and next frames differ. High-action B-frames compression factor should be lower than doing low-action. Slower movements keep much more info from one frame to another and are so much easier to compress. :roll: Maybe no one did this until now because on high-action P and I frames also get much lower quantizers, so the factor's influence will be less. Nevertheless on those scenes it may be too much :? Bilu |
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vb_qfactor=1.2 vi_qfactor=0.8 vb_qoffset=0.75 Formulas explained above. Something like this: Iquant= Pquant * Ifactor + Ioffset Bquant= Pquant * Bfactor + Boffset both factors and offsets are related to P-frames quantizers. In this case B quantizer = P quantizer * 1.2 + 0.75 vqblur=0.3 averages a frame quantizer with previous quantizers, bad for sudden high-action. It would make terror movies even more terrifying ;) vlelim=-4 vcelim=2 vfdct=6 Quote:
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About vfdct, as you can see from both Mencoder's and FFMPEG's documentation the value 6 is not existant or at least not documented. Better should auto (default). Quote:
The only way to get a fair bitrate distribuition is called 2-pass. High bitrates work for 1-pass because every frames gets as good as the max quantizer lets. About parameters, look at my posts above for digitall.doc . Trell, mbd=2,cbp and mv0. At least these got my attention, there may be others around. Bilu |
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Er, what about a 2 pass command example :?: Noone already tested it?. Don't know what to begin with. Willing to have more to play with... :D |
@bilu:
I was posting when you were posting... again, nice explanation in last post. vhelp asked for something like this in other htread: to know what functions to use, and what parameters, and what are those parameters for. This way, we can tweak it better for our purpose. Cool. |
About 2-pass encoding
I don't know which would be better as a 1st pass (when fitting one movie per DVD): 1) Encode with vqscale=2; 2) Encode with avg bitrate = max bitrate; The information would probably be different in all those scenes where vqscale=2 would have gone over the max bitrate limit. And probably the information would be worse, or else there wouldn't be a problem doing 1st passes with vqscales bigger than 2. But on the other side if the 1st pass fitted the DVD there would be no need for a 2nd pass... ;) Bilu |
Sorry bilu, big noob here :oops:
I need, if possible, one or two steps backward...: how do I say mencoder to encode first pass with some settings and second pass with other. I mean: 1st pass: vqscale, vbitrate=vrc_maxrate, 2 B frames, ... whatever 2nd pass: no B frames, vqblur, trell, mv0, vbitrate=desired average bitrate,... Don't know if I explain well myself. I can't still think about how to encode in every pass, if I even don't know how to make mencoder encode in each pass with different settings... if possible. Sorry if I'm like a pain. :roll: |
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Bilu |
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http://www.mplayerhq.hu/DOCS/HTML/en...eat-divx4.html As you see, it's easy :) Meanwhile, I found that I'll use Linux instead of FreeBSD for encoding: http://www.bsdnewsletter.com/2003/10/Features110.html IMPORTANT NOTE: Except for vqscale=2 or vbitrate=vrc_maxrate if used on 1st pass, DON'T CHANGE PARAMETERS BETWEEN PASSES!!!! 8O 8O 8O Bilu |
@ bilu,
which explosion is that from (scenewise) ?? ..the one where the plain lands (the decoy gal is on) or some other scene? I have another scene that I"m working on, which I think is a pretty good one to work with, because it's got low-light in those scenes, and there is lots of fire, and then it finishes off w/ another quiet low-light (red) scene. . . That scenes is from my Fifth Element disk. You can find it at end of chp 6 and leads right into 7. If you got this DVD, take a look, and let me know what you think of it, as a test scenario to use in mencoder/ffvfw etc etc :!: -vhelp |
@vhelp
I don't know what scene it is, digitall.doc didn't told :lol: Big explosions and very fast action scenes are allways good for this sort of test. I have that DVD at home and will take a look, but I trust your judgement - it's an explosion, so it must be good :lol: Off to bed now. Bye. Bilu |
Obligatory reading about Mencoder:
http://www.mplayerhq.hu/MPlayer/rele.../man_page.html http://www.mplayerhq.hu/DOCS/HTML/en/mencoder.html http://www.mplayerhq.hu/DOCS/tech/encoding-tips.txt Note: Most docs are MPEG-4 focused, but there's lot of common information. Bilu |
Hi bilu,
I've U/L'ed that clip I mentioned last night. The one from the dvd, "The Fifth Element".. chp 6/7. There were other encoding tests that I performed on this same scene (ie, TMPG, ffvfw, and now, w/ MEncoder) :!: In any event, since you already have the DVD, (mine is NTSC) You can run your own tests, and compare against mine. See if you get the same results, or whatever. The only problem I still have w/ mencoder is the caos of error messages it spits out. IMO, MEncoder is very picky/fussy about everything !! DOWNLOAD: * 5_enc.m2v -vhelp |
Hi vhelp,
I'm sorry for not having posted about my experiences with mencoder under windows 98 se but right when I was going to try it, the harddrive of the laptop died... Since parts for such an old laptop are very expensive, the company gave me a new one with XP Home preloaded... But I promisse if I find a PC with windows 98 I'll give it a shot. As to mencoder being very picky with options, I haven't been experiencing much messages on my latest trials. Have you downloaded your build from the official site? That's the one I've been using along with the files provided by Vmesquita to recognize makeAVIS. Or maybe the problem is OS version related :? @all Can someone post their experiences with mencoder under windows 98? Cheers |
@ rds,
I've tried the log file thing, but its only for 2pass encodes 8O and I only do one pass :!: - - so, nothing gets writen to file. FWIW, I use the following param in my string for mencoder: Code:
-passlogfile=h:\mencoder\5_enc.txt From the .HTML docs: -------------------- Quote:
I'm really desporate to find out HOW to avoide the errors. It sounds to me, like the settings ALL have to work in concert, else the errors poor out. And, if a given area ina scene is too much for a diven mencoder setting, errors will poor out still. . . I refuse to believe that its an OS thing. We are all working from the same build and same command-line param strings, and values. But, one thing I did notice, and that is, when ever I try others param string (when they are posted) I almost alwasy get a different quality result. Sometimes, I get nothing but green video. ie, when you posted amenophis's code, and I used it as a test, I got nothing but green in my video, but, when I comment that line out, and used MY param string, I got a perfect video (minus the errors, of course) -vhelp |
PS: oh, did anyone D/L the sample I posted earlier here, I did w/ mencoder yet ??
You should be able to open it w/ all apps, except DVD2AVI. Even bviewer opens it fine. I even got the green flat-line in bviewer's windoer :roll: -vhelp |
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