One Pass VBR using CCE question

[trooper11]

I have seen alot of talk about using this option over the normal 5 pass method.

My source is fansub anime and my question is first of all, does OPV actually make a differnce for the source i have. Secondly, if it is, is there anyway of calculating the resulting file size of the video i encode?

I couldnt find any guides that focused on the use of this for dvd video, so I was hoping someone could point me in the right direction. thanks.

[pchan]

I think Fansub Anime video are mostly in Divx format. The guide section have avi to DVD conversion.
https://www.videohelp.com/guides.php?howtoselect=4#4;10
I convert to Divx to VCD format using TMPGEnc and author to DVD with DVD-Lab Pro. Manage to squeeze 16x 23 minutes episodes into one DVD+R.

Here is the DVD authoring guide section.
https://www.videohelp.com/guides.php?howtoselect=3#3

[guns1inger]

One of the problems with OPV, and indeed CQ modes for encoding is that file size is not predictable. If you want to hit a file size then use either CBR or two (or more) pass VBR. Personally, I think anything higher than 3 passes is wasting time, as the difference is not visible to the naked eye, and those who try to defend it end up using bitrate viewers to show distribution, but can't show a qualitative improve to go with the numbers. I certainly would not call a 5 pass method 'normal'. In fact, CCE is one of the few encoders that even allow for more than two passes.

I would stick with half-D1 resolution as you have fansubs and VCD res might make the subs to ugly to read. It also leaves you a bit more res when adding borders. You should do this to make sure the subs don't fall into the overscan area and get obscured (a common problem with fansub work). You can probably get a reasonable 4 - 4.5 hours to a disk.

A bitrate calculator will tell you the bitrate to use as an average for VBR for a given length of video. Just add up the run times of your episodes, put the total in, and use the results. If you use 2-pass VBR with this figure as an average, or as the bitrate for a CBR encode, your file size should be pretty predictable.

[trooper11]

well i have done this alot, but previously i just used tmpgenc to convert the video (after removing the audio) using the 2 pass method ect.

but sometimes im working with dual audio anime or video in the form of H.249, so its higher quality then say your average xvid encode.

so i decided to try out CCE and see if it makes a differnce. i just assumed using a 5 pass method was standard far since ive seen it in many CCE guides. if it is a waste of time, its not that big a waste considering its still faster then my tmpg encodes using only 2 passes.


it sounds like to me that there is no big difference in OPV or 'standard' 3-5 pass methods, so ill just stick with what has given me good results.


i usually stick to 9 episodes per disc for H.249 encodes or particularly good xvid encodes just to be safe. that usually leads to a bitrate of 2500-2600, which results in great quality on the dvds in my opinion. of course i wouldnt say its the same as a real one, but its close enough.

[trooper11]

oh and about using half res D1, i hadnt tried that before.

i always encode to 720x480 and simply run a resize on the video if the subs are hardcoded, such as addng borders to the top and bottom, but every anime is differnt, so the resize is always different.

if im lucky, i get some anime with soft subs so i just encode to 720x480 wihtout any resize and add the sub file during authoring

[guns1inger]

I would stick with 2- 3 passes and get more encoded in a shorter time. At least try it and see if you can tell the difference. Personally, 25 - 2600 at full-D1 would be too low for my tastes, even with reasonable quality source material.

In my experience, OPV and CQ methods aren't worth the time saving. I recently used CQ using Procoder, just as an experiment. Runtime was 87 minutes. The calculated bitrate was around 6100 (leaving room for audio and overheads). The CQ encode resulted in a file a little over 428MB in size. Something very wrong there. A 2-pass VBR got me within a MB or 2 of the predicted size, with lovely quality.

[FulciLives]

Statically doing more than a 5-pass VBR is a waste of time.

I normally only do a 3-pass VBR with CCE but sometimes I will do a 5-pass VBR if I think the movie is "hard" to encode, i.e., I'm using an AVERAGE bitrate lower than I would like (due to long running time) and/or the movie has a lot of "fast action" sequences.

So doing a 5-pass VBR has it's place but no it really is not the "norm" and doing more than 5 is definately a waste of time.

- John "FulciLives" Coleman

[trooper11]

so a bitrate of 2500 is not a good idea?

then there must be a very big boost in quality by aiming for a 5000 or 6000 bitrate. but at that point, i would be forced to limit the number of eps i can put on to something like 4.

when i have a 100+ ep series, thats a heck of alot of dvds id be using, double what i normally use. is the extra quality really worth that?

[FulciLives]

so a bitrate of 2500 is not a good idea?

then there must be a very big boost in quality by aiming for a 5000 or 6000 bitrate. but at that point, i would be forced to limit the number of eps i can put on to something like 4.

when i have a 100+ ep series, thats a heck of alot of dvds id be using, double what i normally use. is the extra quality really worth that?

When using Full D1 resolution (720x480 NTSC or 720x576 PAL) the "rule of thumb" is to not go below 4000kbps as your AVERAGE bitrate.

So 2500kbps is WAY too low IF you are using Full D1 resolution.

If you are using Half D1 resolution (352x480 NTSC or 352x576 PAL) then you can go lower and 2500kbps now makes sense although I prefer to use 3000kbps myself when using Half D1 but it is somewhat subjective.

- John "FulciLives" Coleman

[trooper11]

hmm well what does using half res D1 actually produce?

i guess the thing im having a hard time understanding is what that res actually means. wouldnt 352x480 look odd on a TV with extra black borders?

wouldnt that also force my source material to be downsized to fit? the source is 640x480, of course i have to sometimes resize it with black bars on top and bottom so subs will show up, but those black borders dont show up on the screen.

so does using half D1 actually mean a step down in quality versus 720x480 and a proper bitrate of 5000 or 6000 for example?


i guess i could just try out a disc in 720 using a higher bitrate and see if there is a night and day difference.

[FulciLives]

The DVD player will "stretch" Half D1 so that it fills the screen in such a way that the aspect ratio looks normal but you have half the resolution width wise which gives you a slightly "softer" looking image but you also need a lot less bitrate to avoid MPEG compression uglyness.

Try Half D1 at 3000kbps CBR then try Full D1 at 5000kbps CBR ... just do a few mintues worth ... burn boh on a DVD and play it back and see for yourself.

- John "FulciLives" Coleman

[trooper11]

ok but thats using CBR not VBR.

the whole basis for VBR is that it uses more bitrate for one scene over another, your just setting an average to aim for and the extra passes help to make that more accurate.

so is there still a big differnce between 2500 VBR and 5000 VBR? i always set my high end for 9000 and low end for 2000, so its never going to bottom out.

what ill try first is two full D1 encodes, one at 2500 avg VBR and then one 5000 avg VBR

[guns1inger]

If you set a low of 2000 and an average of 2500 then the encoder will rarely get over 3000 in order to maintain the average. The ideal is to have the avreage at approx the halfway point between your high and low levels. I would drop the low to around 500 to give the encoder more headroom. Your don't need to arbitrarily waste 2000 on black credits with wihite text (for example)

[trooper11]

ok so whatever avg i choose, it would be better to set the low end at 500?

i was thinking about upping the bitrate to 3000-3500, try and keep 7 or 8 eps per disc and see if its any difference

[FulciLives]

I just said CBR because I was suggesting you do a "sample" and see how it goes.

What I said before still is accurate ... don't use an AVG of below 4000kbps with FullD1 resolution. This will result in a lot of uglyness UNLESS you have a really clean source and even then it is debatable.

Nothing wrong at all with 3000kbps - 3500kbps but you better be using HalfD1 at those bitrates.

- John "FulciLives" Coleman