The Coolness of B-Frames

[DeathTheSheep]

Yeah, I've heard all the hype. I see it written about in posts all the time. Never a day does pass without questions pertaining in some form or another to B-Frames ("When are B-Frames gunna be enabled for AVC?!!!!"). But now I must ask, what the heck is up with B-frames anyway?

I heard they are a form of bidirectional frame encoding/rendering. At this, I scratched my head long and hard and almost pulled a "pancake bunny." So what?!

B-Frames are complicated, they take long to encode, they are BLOCKY as HECK, and they increase filesize. Need I upload a sample with and without B-Frames fer y'all to see? Why don't people stick to the IPPPPPPPIPIPPPPPPPPPP... method? Complexity? If so, I don't see it.

So what is all this B-Frame craziness? What use to they serve? Or are they only useful at collosal bitrates (yeah, I'm livin the >56kbps road)? NeeheeharharharHAR.... No, seriously,
Inform Da Sheep Afore He A-Kills Hisself...BAAAa

[Sirber]

B-Frames are complicated, they take long to encode, they are BLOCKY as HECK, and they increase filesizeNot really. They aren't much slower to encode, they aren't much more blockier, and they decrease the filesize like hell!!! :D

[DeathTheSheep]

DE-crease? No way... Wierd... OK, I'll check it out... hei.....

Wat should I be a-puttin fer my max b-frame on anime (I like anime) at quant of 45 at around 7fps?

Or wat 'bout high br like 31 at 23.976fps?

[Gabriel_Bouvigne]

B frames decrease the overall size because:
*you can get better prediction using 2 refs
*often you can choose to quantize them more, as in mpeg-1 up to mpeg-4 asp they are not used as reference for other frames.


Btw, proper English is easier to understand.

[Leak]

Originally posted by Gabriel_Bouvigne
Btw, proper English is easier to understand.

Yeah, by the sound of it that has to be some seriously weird grass he's munching... :D

np: Yoko Kanno - Yakitori (Ghost In The Shell Stand Alone Complex OST 1)

[bond]

Originally posted by Leak
Yeah, by the sound of it that has to be some seriously weird grass he's munching... :Dlol ;)

[akupenguin]

I have to say that even though B-frames work in practice, I have a mild philosophical aversion to them. This is partly based on my experiences in implementing them (not too bad, but there's a zillion things to keep track of), and partly rubbed off of Michael Niedermayer. But I still think that 3D wavelets are so much more elegant, if only they could be reconciled with motion compensation. (And I am reading some papers that try to do so, but I haven't implemented any of them yet.)

[DeathTheSheep]

Yeah, by the sound of it that has to be some seriously weird grass he's munching...

Indeed, my grass happens to be a trifle tainted with a bit of "shwacker." Thus, I become mildly shwacked at periodic intervals. Perhaps a revision of my written language is in order.

Ah, I've been rather infatuated with the principle of "Wavelet" codecs, and hope some day a professional development group will shine such a codec onto the video market for public use. Needless to say, said codec must be fairly primed prior to evaluation.

I've also heard that VP7 utilizes some form of wavelet technology in its codec implementation. I don't quite recall, but I vaguely remember something to the effect of its utilization of "discrete cosine formation" or perhaps some other such wavelet-based technology...

Regardless, AVC B-Frames seem to decrease the overall quality of my encodes. This is especially conspicuous at lower bitrates (such as those attained by means of utilizing a quantizer of 45) at no significant decrease in filesize. At higher bitrates (those correlating to quantizers not exceeding 34, predominantly), the decrease in filesize makes up for the quality loss, for a quantizer of, say, 31 would produce the same filesize as 29 would with B-Frames.

[akupenguin]

Originally posted by DeathTheSheep
At higher bitrates (those correlating to quantizers not exceeding 34, predominantly)
Maybe it just depends on what you're encoding.
I consider QP=20 to be medium bitrate (1 mbit/s at dvd res with B-frames), and QP=30 to be low bitrate and untolerable quality (300 kbit/s). But then, I used MPEG-4 ASP at QP=1 too, because QP=2 just wasn't good enough for some scenes.

[Didée]

If I recall correctly from other threads, DeathTheSheep is aiming for crystal clear quality with 2-digit bitrates (<100) or something like that ...
Oh, how comes the "a man claims to store multiple movies on one floppy disk" thread springs to my mind.

[Shinobu]

But then, I used MPEG-4 ASP at QP=1 too, because QP=2 just wasn't good enough for some scenes.

if think avc is a very destructive codec, like the mpeg4.
the only no-loseless codecs witch give me realy good quality at hight bitrate and 720*576 resolutuion (>3500kbps) are mpeg2 (about 8Mbps) and snow iframes only (because of the strange green and violet temporal color degradation).

i think each codec is designed for different usage, that's why you'll never be able to make as good looking xvid thant mpeg2 at 8 mbps, yes you'll have some very close result with and xvid full ana @ 2500 or 3000 compared to a 8mbps mpeg2 full ana, but you'll never had as good quality than mpeg2@8mbps with xvid (full ana 720*576).

i got some hdtv sample in mpeg2 (don't remember the exact bitrate but probably about 15/20mbps and 1088p 16/9) and i've never be able to get as good looking movie with xvid, and i tried lots of custom matrix and even at quant 1 xvid was realy not as good as mpeg2...

sorry for the of topic, but it's true h264 is realy a great codec, and i'll use it a lot for some of my backup, but if a realy want a perfect quality at hight bitrate i'll use mpeg2 or maybe snow (when it'll become backward compatible).

++

[Gabriel_Bouvigne]

If your source is in mpeg-2@8Mbps, of course the mpeg-2 is the best, as it IS the source.

If you really want to compare let's say Xvid vs mpeg-2, you should decompress your source and recompress it in mpeg2, otherwise you are not really comparing mpeg-2 efficiency.

[Didée]

Shinobu:

Do I understand you correctly that you took an mpeg-2 source, and didn't get e.g. XviD to look as good as _the source_? If so, then my answer is "oh, c'mon!!".
Of course mpeg-2 must be coded again, too. AND: since really *raw* samples are not so common, and most testing is done with input that is already mpeg-2, the source *must* be *altered* before the comparison. At least, it must be cropped by a non-MOD8 amount. If not done so, then the source offers a block alignment (and block content as well) that clearly favours the mpeg-2 encoder over the mpeg-4 (ASP) encoder, since the characteristics are of the same type.
On top of that, one should add a rather small amount of noise, ideally on a subpixel level.

Analogy: take an MP3 as source, and then try running tests on that source in order to find out wether Vorbis or MP3 can compress that source with higher quality. Of course, that test is 100% b0rked.

[Shinobu]

of course i've done transcoding of mpeg2, i'm not stupid, i thought it was clear in my post.
and i've done lots of test too with dv source and analog loseless sources 720*576, and my conlusions remain the same.
but don't forgot that's my impression over my tests, i doesn't use psnr nor stuff like that, only some pairs of eyes and some blinded source ^^.
++

[ObiKenobi]

Originally posted by Shinobu
yes you'll have some very close result with and xvid full ana @ 2500 or 3000 compared to a 8mbps mpeg2 full ana, but you'll never had as good quality than mpeg2@8mbps with xvid (full ana 720*576).

Ummm...how is it fair to compare an XviD encode at 3 mbit to an Mpeg2 encode at 8mbit? The fact that it can look good with a bitrate 5mbit bigger isn't really some great feat, and if it in fact needs that much extra bitrate to look better is definitely not a good thing. I think it would be alot more fair to compare how good the Mpeg2 encode looks at 3mbit compared to an XviD at 3mbit (or any bitrate as long as they were equal) to get a more fair comparison, and I believe in many cases you'd see that XviD would give you as good if not sometimes better results.

This would be like saying that you could make an Nero AVC encode at 10 mbit look better then a DivX at 500kbit (which I think is pretty obvious), but is that really a fair comparison that provides any meaningful information considering the huge bitrate disparity? Not really.

[Sergei_Esenin]

Most "better quality" people think they see in MPEG-2 over MPEG-4 tends to be due to renderer or postprocessing differences. Widely used MPEG-2 playback software tends to turn on postprocessors like CLEV or NVPP by default, and if MPEG-2 playback takes place within a different application than the MPEG-4 playback or within different windows of the same application, it may use an altogether different renderer.

Then the quality and settings of the encoder are a third issue. With due respect to DivX, 3ivx, and NeroDigital ASP, they can't encode nearly as well as XviD with optimal settings. A fair comparison requires the optimal encoder with optimal settings.

Then the quality of playback filters is yet a fourth possible culprit, because ffdshow, XviD, DivX, Nero, and 3ivx can each produce subtle visual differences given the same MPEG-4 stream, even without postprocessing. People like to think of playback filters as largely interchangeable since they all attempt to conform to the same standards, but they each have minor variations. This has been acknowledged about MPEG-2 decoder filters for a long time, but is largely ignored in MPEG-4 decoder filters. And, any quality-robbing postprocessing options must be off, because deblocking and other features don't help at high bitrates, they diminish detail.

[DeathTheSheep]

a man claims to store multiple movies on one floppy disk

MWAHAHAAHAHAAA! You've figured me out!!! :devil: Actually, AVC at low bitrates is optimal for anime/cartoons. I ain't encodin' Matrix3 or nothin'.

Heh, I use junk at around 320*240 or less, not junk in the thousands of pixels range...

MPEG-2 sucks at low bitrates, no matter what the encoder or renderer happens to be, or so I've heard.

XVid can't even *reach* low bitrates (compare it to DivX Fusion at quants of 21+). And the closest it gets leave the most horrible trails of artifacts compared to any other ASP codec... Come now...

Certainly at the highest bitrates, 8mbps MPEG-2 or Quant 0/1 MPEG-4 or even emerging snow at 0 would give some good-a$$ picture....

But really, I'd like to see 8kbps encodes. Well, not really, but I doubt you can store much video on some trash like a 512MB memory card if yer usin' some old 8mbps MPEG-2.

A 45 quant on anime gives OK results with anime. The hardsubs are readable and everything at filesizes of UNDER (breakthrough) 2MB for a 20 minute episode. Of course, B-frames ruin this, rocketing the filesize. B-frames also wrecked MPEG-1 for exteremely low bitrates.

So, no, I don't really want to fit multiple movies on a floppy disk (one 512 MB memory card would suffice), but I most certainly don't want to stick on 8mbps MPEG-2 on.

[ObiKenobi]

Originally posted by DeathTheSheep
But really, I'd like to see 8kbps encodes. Well, not really, but I doubt you can store much video on some trash like a 512MB memory card if yer usin' some old 8mbps MPEG-2.

A 45 quant on anime gives OK results with anime. The hardsubs are readable and everything at filesizes of UNDER (breakthrough) 2MB for a 20 minute episode.

What size screen are you watching these on? Cause I've made encodes at this size and watched them on my PC, 17" LCD, and they look like absolute garbage. The quality reminded of the horrid 5meg DBZ fansubs that used to float around.

Originally posted by DeathTheSheep
Of course, B-frames ruin this, rocketing the filesize.

This still doesn't make any sense. A B-frame more compressed then a P or I frame and will always lead to smaller filesizes when used, as many frames that would have been lower quant P frames become higher quant B frames, unless you are just doing something absolutely wrong.

[DeathTheSheep]

IPPPPPPP sequences always increase quality over B-Frames in exteremely low bitrates. Bidirectional references are counter-productive when it comes to double-digit bitrates. I don't know why this is, but it absolutely destroys the hardsubs, wrecks movement, and increases filesize by a marginal degree.

Perhaps merely the sequence differentiation in itself is enough to boost the filesize just enough to overtake any possible benifit those destructive B-frames could offer... while reducing quality considerably.


Resolution: 320*240. ~7/8 fps. Deblocking 6/6. 30+ references (for best prediction). 45quant. Anime source.

[ObiKenobi]

Originally posted by DeathTheSheep
IPPPPPPP sequences always increase quality over B-Frames in exteremely low bitrates. Bidirectional references are counter-productive when it comes to double-digit bitrates.

In my experiences at lower bitrates B-frames are much better at increasing quality, but at the bitrates you encode at it looks like garbage with or without b-frames so to me encoding at such a low bitrate is worthless.

Originally posted by DeathTheSheep
Resolution: 320*240. ~7/8 fps. Deblocking 6/6. 30+ references (for best prediction). 45quant. Anime source.

Yes, but what is that being watched on was the question. Cause on any decent sized PC monitor that looks like complete garbage to me and even on a PDA that looks pretty bad. But I guess if it looks good to you that's all that matters.

[RadicalEd]

It is remotely possible for B frames to increase size indirectly, especially if they're not being overquantized with respect to the Ps. This is because a B frame essentially creates a void in prediction and the next P frame has to jump behind it and use the P (or I) frame before the B to predict from. Therefore P frames get bigger as a result of B frames. This is probably more prominent with anime as well, so maybe that's what sheep is experiencing. Still, there's no way encodes like that look good to anyone who doesn't have glaucoma.

[DeathTheSheep]

There's no way encodes like that look good to anyone who doesn't have glaucoma.

With B-frames, true. Otherwise, naa. (Or should I say, baa). Yeah, its on a PDA through an experimental AVC decoder. Also, I've shared some samples with people and they thought it was "easily watchable" but "prefered" original quality better. Wow.

Yeah, with B-frames, the in-loop filter (which is so relied on) is destroyed. Also, B-frames have a lower quant than I/P frames, and at 47, it looks one heck of a lot worse than at 45, so the quality is very inconsistent, and the subtitles are unreadable for a few ms and readable the next.

Yeah, it's the prediction reference gap. Solved with tons of refs (30+) and no B-frames.

I can make an average episode 1.8-2.1MB without B-frames, and 2.0-2.4MB without them, and with easily noticable decline in quality. Yep, it's anime, yep, it's probably the P-increase.

In my experiences at lower bitrates B-frames are much better at increasing quality

BAAAAA!! :sly: :p Well, well... anyone know where I could upload a couple of 1minute samples? You know how tiny the filesizes are... I'll just need lambchps--I mean, proof. MUHAHEEHEEAHHAHAR. Only with higher bitrates do B-frames help (Under 38q).

Thx ppl.

[ObiKenobi]

Originally posted by DeathTheSheep
With B-frames, true. Otherwise, naa. (Or should I say, baa). Yeah, its on a PDA through an experimental AVC decoder. Also, I've shared some samples with people and they thought it was "easily watchable" but "prefered" original quality better. Wow.

Which for me would mean it would again look like complete garbage.

Originally posted by DeathTheSheep
BAAAAA!! :sly: :p Well, well... anyone know where I could upload a couple of 1minute samples? You know how tiny the filesizes are... I'll just need lambchps--I mean, proof. MUHAHEEHEEAHHAHAR. Only with higher bitrates do B-frames help (Under 38q).

Except "low bitrate" for me is around the 500-800 kbit level, not the double digit bitrates you encode, because like I said before anything encoded at that level just looks like garbage to me.

[dragongodz]

the simple fact is that B frames do increase quality with lower bitrate encodes. look at mpeg2 and mpeg4ASP(xvid) and you will see they do.

however AVC is still very new and i remember akupenguin saying in another thread that B frames for x264 are not optimal yet. he even suggested only using 1 Bframe for the time being so that should tell you something.

[DeathTheSheep]

Originally posted by ObiKenobi
Which for me would mean it would again look like complete garbage.



Except "low bitrate" for me is around the 500-800 kbit level, not the double digit bitrates you encode, because like I said before anything encoded at that level just looks like garbage to me.

Here's to my defense (although sheep like me are really only meant for eating)
Mm... Imagine an anime source with strong, thick borders and high contrast. Now picture an episode at 320*240 on a Pocket PC. Readable, watchable, no prob.

However, a similar encode of Matrix3 with subtle borders and shading stretched to 1280*1024 on a plasma screen=death. And not for sheep, but for eyes. Yeah, I see what you mean.

So yeah. Samples are coming soon, with the most optimal B-frames yet--those included in the newest sEx264 (which actually DO increase compression, but reduce quality to an unbelievable extent...I liked the older ffdshow B-frames better, even though they DID make the file bigger)...lol

[708145]

Look here (http://www.funknmary.de/movie/) for the example that this grass munching sheep is talking about.


As it turns out, sEx264 does the best job with the B-frame
compression, so I used the newest version in these tests. And it
turns out there IS a filesize decrease... but once you see the
samples, you'll be surprised... Read sample.txt in the zip for info,
lol!


bis besser,
Tobias

[ObiKenobi]

Originally posted by DeathTheSheep
So yeah. Samples are coming soon, with the most optimal B-frames yet--those included in the newest sEx264 (which actually DO increase compression, but reduce quality to an unbelievable extent...I liked the older ffdshow B-frames better, even though they DID make the file bigger)...lol

All I see when watching these samples are complete blocky messes with barely readable subs. I see nothing to really differentiate the version without b-frames from the one with b-frames as they are both garbage. I see no pratical purpose for encoding something with such an extremely low bitrate unless you just wanna see how crappily something can come out.

[skal]

Hi all,

Originally posted by RadicalEd
It is remotely possible for B frames to increase size indirectly. This is because a B frame essentially creates a void in prediction and the next P frame has to jump behind it and use the P (or I) frame before the B to predict from. Therefore P frames get bigger as a result of B frames. This is probably more prominent with anime as well.

Thou speaketh wisdom, Radical Ed ;)
B-frame are good are inserting 'half-way' pictures between two close P-frames. You could even double the frame-rate at allmost no cost by systematically inserting a b-frame between each p-frame. But now, considering the frame rate (7/8 fps!) DeathTheSheep is using, the extremal P-frames are not temporarily close enough to permit a good temporal interpolation using a b-frame. Successive frames bear too few
resemblance to be bframe-friendly at such a framerate... Hence not only are b-frames bad at doing their job, but the p-frames are getting worse too, due to increased temporal distance. In fact, i think any content/resolution encoded at too low framerate (<10 Hz, say) is likely to be bframe-unfriendly as hell.
Just my 0.02euros.
-Skal

[DeathTheSheep]

And
Thou speaketh wisdom
as well, skal! 'Tis that which I had originally forseen... Frame discrepency gaps impede accurate B-frame estimation...

Now, however, a new question does arise, one that can be accurately summed up with the ensuing clever lines of prose:

Tell me why,
Pray tell,
The B-frames are blocky
As hell

For I
Don't see
Why oh why
That could be

A-Hem... So yeah.

[OT] skal... skal... Pardon me if I don't accurately recall, but...

Ain't you teh fella workin' on a sleek new AVC codec? I tried out yer ASP, and it sure works!

[ObiKenobi]

Originally posted by DeathTheSheep
Tell me why,
Pray tell,
The B-frames are blocky
As hell

For I
Don't see
Why oh why
That could be

It's cause you are quantizing them so high (the higher the quantizer the more data has to be eliminated from each macroblock which is causing that hideous blocking) and that's just a side effect. Considering that every frame in those encodes are nothing but a mass of blocks it's not that surprising that the b-frames would be blocky as well as they would be quantized even higher then the p-frames.

[Tommy Carrot]

Originally posted by ObiKenobi
It's cause you are quantizing them so high (the higher the quantizer the more data has to be eliminated from each macroblock which is this hideous blocking) and that's just a side effect. Yep, but another reason is: ffdshow cannot deblock AVC b-frames, that part of the deblocker filter is not completed yet.

[DeathTheSheep]

HAHHAHEHEHEHEHEHEHEHE

I think that this does the explaining all too well.

With B-frames:
http://img148.exs.cx/img148/8042/bframe5zz.jpg

Without:
http://img148.exs.cx/img148/8250/nobframe7lc.jpg


Get the picture? Heheh, get it?

B-frames increase quantization by ~2q. At these bitrates, my gosh... that's one heck of a quality decrease.

Windows media dynamically inserts B-frames into wmv content based on computer ability. Heh, I got an 8fps clip runnin smooth as heck at 120fps with this... it's exeedingly visually pleasing. Well, if not B-frames per say (must be integrated and conform to standards...GAA), they utilize the same principle: they stick in mid-frame estimates.

Is there a way to do this with non-wmv encoding? Or is it something specifically designed into the format? Or is MS just plain cheating with hack-like principles?

[ObiKenobi]

Originally posted by Tommy Carrot
Yep, but another reason is: ffdshow cannot deblock AVC b-frames, that part of the deblocker filter is not completed yet.

Though even with deblocking on for the other frames it still looks pretty bad... I can't imagine deblocking for b-frames helping out at all and in fact with deblocking enabled those clips looked even worse.

[ObiKenobi]

Originally posted by DeathTheSheep
HAHHAHEHEHEHEHEHEHEHE

I think that this does the explaining all too well.


Get the picture? Heheh, get it?

Except every single frame (regardless of b-frames are being used or not) look just as bad as the first picture.

[DeathTheSheep]

Um, why the heck does the IN-LOOP filtering not work? Eh... That's integrated into the encoding itself and ain't dependent on the decoder/renderer. It sure works on P and I frames.

[DeathTheSheep]

@ObiKenobi

Hey! <Snort, baa> that ain't so!! compare especially the second short samples. There are no "blocks" in the IPPPPPPP sequences; at most, all I can see is a tiny trace of an outline around areas of consistent color. B-frames give the true garbage.

I can see the quote:
But mista sheepy dude man dude fo wtf iss ALL "garbage" what choo talkin' bout...?

Remember, it's a tinseey weensey 320*240 screen. The blocks stick out like crazy man.

[edit man]
OK. Lookit quant 42 samples. up to 38. The blocking is astounding for B-frames!

Quote me on this: The results are a lot better with lower quant than those obtained with a higher B-framed quant at the same filesize in quants of 38-47. (In terms of blocking and overall quality)

[ObiKenobi]

Originally posted by DeathTheSheep
@ObiKenobi

Hey! <Snort, baa> that ain't so!! compare especially the second short samples. There are no "blocks" in the IPPPPPPP sequences; at most, all I can see is a tiny trace of an outline around areas of consistent color. B-frames give the true garbage.

I can see the quote:


Remember, it's a tinseey weensey 320*240 screen. The blocks stick out like crazy man.

Umm...you must be blind. I am watching the files at 320x240 and the blocking is apparent not only in the one with b-frames but the one without b-frames. Turning on deblocking in ffdshow doesn't help in the least bit it still looks like a non-detailed blocky mess with subs that are barely readable. Like Ed said the only person who could think this looks good must have glaucoma. I'll post some screenshots just to prove what I'm saying. Even at 1/2 and 1/4 resolution it still looks like crap.

[DeathTheSheep]

Ah, you mustn't be so hasty. 3*2.5 inch screen, and lack of detail=not important. Just blocks. I'm not tryin' to force my way of seeing (COUGHspreadtheglaucomaCOUGH)... I'm just tryin' to find out if there is a way to turn in-loop filtering/block prediction on B-frames. With that addition, B-framed clips rock (coughyeahsurecough).

:D oh, and check out the edit to the above post, heheh

Quote me on this: The results are a lot better with lower quant than those obtained with a higher B-framed quant at the same filesize in quants of 38-47. (In terms of blocking and overall quality)

Yeah, compare a 28.8kbps anime clip without b-frames to a 28.8kbps clip WITH b-frames... or a 56k clip ... or even a 92kbps clip... and you'll see the blocking. I can accept detail smearing. I hate blocks. (Although the BLOX codec is ok...it doesn't block! muhaha)

[ObiKenobi]

Here's pictures from each of the encodes:

With B-frames
http://img153.exs.cx/img153/8096/withbf9gt.png

No B-frames
http://img153.exs.cx/img153/8227/nobf9uy.png

There is little to no difference between these encodes as they are both just a blocky mess, though at this frame the one with b-frames looks slightly more detailed. I'm sorry, but to say that either one of these looks "good" means you must seriously get your eyes checked cause there is a problem.

[ObiKenobi]

Originally posted by DeathTheSheep
Ah, you mustn't be so hasty. 3*2.5 inch screen, and lack of detail=not important. Just blocks. I'm not tryin' to force my way of seeing (COUGHspreadtheglaucomaCOUGH)... I'm just tryin' to find out if there is a way to turn in-loop filtering/block prediction on B-frames. With that addition, B-framed clips rock (coughyeahsurecough).

Except I'm not watching it at the full resolution of my monitor. At 1/2 and 1/4 the resolution of the file that would easily mimic what it would look like on your PDA and it still looks like crap.

[DeathTheSheep]

You got em on a P-frame, man, when the blocks have already been washed out, probably, or one where there is low motion taking place. I'm talking about blocking while there is movement. Also, the second screenshot is working off a slightly lowered entropy rate, so the data was more easily predictable and the encoder didn't bother to apply detail to that specific frame.

Remember, a screenshot of a specific frame can prove just about anything, and in any direction. I'll come back with proof supporting motion blocking (come on, its a known fact baaaaaAA that B-frames stuck between P frames that far away from each other leads to heavily decreased motion accuracy, especially in anime, where short jolts of motion are depended on to convey an image.

So yeah! :D I rule :D I drool :D (Please don't make me into p-p-poisonous lambchops...or worse yet, lamB-framechops. (see how that b-frame caused a choppier word and ruined its consistency and understandiblity? Not to mention innacurately predicting the word)

So, anything to my previous questions?

1. In-loop filter possible on B-frames?
2. Dynamic B-frame insertion like wmv's?

[DeathTheSheep]

Eh, and some people think Xvid at quant=2 looks like trash, too, not to mention my favorite...31...

[]Edit, oh man... B-frames trash up ASP codecs pretty bad, man. DivX fusion, set to adaptive multiple consecutive, gives you a tremendous filesize in my preliminary tests...

[Tommy Carrot]

Originally posted by DeathTheSheep
Um, why the heck does the IN-LOOP filtering not work? Eh... That's integrated into the encoding itself and ain't dependent on the decoder/renderer.
Ahh, it's not so simple. The deblocking on the encoder side simply helps in better predictions, but for actual deblocking, you have to support it on the decoder side too.
I can accept detail smearing. I hate blocks.
If you hate blocks so much, you should use Snow codec instead of x264. True, it has even worse quality at those ultra-low bitrates, but guaranteed no blocks. :D
1. In-loop filter possible on B-frames?
2. Dynamic B-frame insertion like wmv's?
Sure, both possible, just not implemented yet.

[DeathTheSheep]

Yeah!! Wavelet forever man!! Go rududu!!! :D

(wavelet decoding isn't supported on PPC, even in theory, but i suppose someone could try it...:D)

[DeathTheSheep]

Originally posted by Tommy Carrot
Sure, both possible, just not implemented yet.

yet. yet. yet. ever hear of yeti3d? man... it rocks

GAAAAAAA!!! ASP had fifty years to get it done!! (heheh, who the heck wants dynamic B-frames? And in already-complex AVC? Besides maybe some sheep that is, quite frankly, very close to death, AHAH, no.)

But in-loop filtering is a huge plus....

[DeathTheSheep]

Eheh, I think I'll pass. Let me work one up for you, man! And at a lower quant. Baa! :p

Ah, here goes.

Bframes: (not same frame according to VDub, because B-frames through off frame count, another example of B-frame coolness hehe)

As you can see, b-frames give terrible blocking while movement is taking place, and I can't tell what the heck is going on. How many characters do you see? Maybe no the best example, but you get the point. Sample 1, frame 58 (B) or 55 (P):
http://img49.exs.cx/img49/1268/bf0jl.jpg

NO BF
While still pretty blurry (as i said, not the best example), it's a heck of a lot worse. I'll try higher br later. How many characters are there? Fundemental estimation difficulties with low framerate.
http://img49.exs.cx/img49/6277/nobf6bb.jpg

Convinced?

[stephanV]

uhm

what the hell is supposed to be on those 2 pictures??? i only see crap, b-frame or not.

[Gabriel_Bouvigne]

How many characters do you see?
Zero. There is some signal, but I am totally unable to see what it could be.

[RadicalEd]

The problem with your comparison is that you're using constant quants to encode. The idea of B-frames is that they reduce size so that more can go to other parts of the video. Of course a B-frame encode is going to look somehow worse than a P-frame encode at the same quant (with offsets), it's the difference between same-size files that matters.
Not that I think you'll get much better results that way, it's pretty clear that b-frames are not good under these (very rare) conditions.

[Sirber]

Originally posted by stephanV
uhm

what the hell is supposed to be on those 2 pictures??? i only see crap, b-frame or not. +1.

Is that a video? Who enjoy watching that? :o

[Mug Funky]

oh, i get it. it's art.

[Dhampir]

Originally posted by DeathTheSheep
Convinced?

Convinced of what Sheep? That each one looks horrible? If that was the point I've been convinced.

Originally posted by stephanv
what the hell is supposed to be on those 2 pictures??? i only see crap, b-frame or not.

My thoughts exactly.

[dragongodz]

DeathTheSheep - thank you for the pictures. now we can easily see what you mean. BOTH look terrible and unwatchable. this is not a B frame problem but a way, way, way to little bitrate problem.
oh and comparing a B frame to a P frame will not prove any point either. you need to provide a couple of short clips so people can see it playback or at least compare P frames from both clips aswell.

[Dhampir]

Here (http://www.funknmary.de/movie/) is where the samples are. They are quite hideous to watch whether they have b-frames or not.

[SeeMoreDigital]

Originally posted by Dhampir
Here (http://www.funknmary.de/movie/) is where the samples are. They are quite hideous to watch whether they have b-frames or not. All the samples are Mpeg4/AVC. And they've all been encoded at less than 40Kbps... with audio!

While I admire DeathTheSheep's persistence and enthusiasm in trying to find a codec that can generate encodes at low bit-rate... I can't help feeling that many people have been drawn into this "Coolness of B-Frames" discussion under false pretences!


Cheers

[skal]

Originally posted by DeathTheSheep

Tell me why,
Pray tell,
The B-frames are blocky
As hell

For I
Don't see
Why oh why
That could be



" Thou shall not munch P-frames" shall be thy answer ;)


More seriously: i'm certainly not able to say for sure why your b-frames are a block soup, but one thing is for sure: the surrounding p-frames are already a mess, so one can hardly expect the b-frame to look real better.

Not, a piece of hint that might help you get better encode at that bitrate/framerate. Let's look at 3 frames at ~8fps (the upper ones in the following -ugly- sketch), and watch the coding in progress:


http://skal.planet-d.net/munch_me.jpg


Arghh! When the encoder is coding frame P1, look at what he has as reference! It's P0, coded at QP=45. A mere block feast!
Question: How do you expect to ME to find a good match between frame P0 and frame P1 ??? The first one is a block soup, but P1 still has lot of details. One could pick any block from the first frame and match it with the third, with a SAD of ~51340986542 (roughly) ;)
The motion vector field will be erratic, and the middle b-frame will find it difficult using the mighty BDirect mode (not to mention that it'll be hard to match the frame P0 / P1, too).

Now the hint: you should make an intermediate encode at less brutal bitrate/framerate (say: 200kbps @ 15 Hz), and use this as a source for the final encode. Instead of trying to jump directly at the extreme settings. This is shown in the last row of pics above. Matching midly decimated pics (QP=32) might be easier for ME.


just my 0.02euros, as usual.

-Skal

[yaz]

hmm ... what about making an intermediate 'hi-def' reference stream by downsizing and downsampling to the desired scale but using one of the lossless codecs or using sg like xvid w/quant=1or2 and w/I-frame only. (it'd be sg like 'capturing' the source) this way u can also check whether this stream is watchable at all. w/that fps it seems like rather a cartoon not a film to me.

the bests
y

[/EDIT]@SMD
that's all i have about the 'coolness of b-frames at the moment :-))[EDIT]

[DeathTheSheep]

Wow. :goodpost: :goodpost: :-) Good advice, I s'pose.

DeathTheSheep - thank you for the pictures. now we can easily see what you mean. BOTH look terrible and unwatchable.
I revised my tests and now use much lower quantizers and full framerate.

w/that fps it seems like rather a cartoon not a film to me

Yeah, it is! lol
you should make an intermediate encode at less brutal bitrate/framerate (say: 200kbps @ 15 Hz), and use this as a source for the final encode.

But as you shall soon see....
However, now I AM trying a less brutal framerate (24fps vs. 7-8fps) and a less brutal quantizer (31 instead of 45). (Like proposed intermediate, kinda).

The results? The B-frame encoded clips are terrible. TERRIBLE. The motion is so horrendous, and the quality is EXTEREMELY inconsistent.

Screen of EXACT SAME FRAME (same thing happens for just about every frame, too, not just this one. I'd say 1/3 or at max 1/6 frames, and even worse, some of them.

Screen:
NO DANG B-FRAME MADNESS!! Smooth pic (AND SUPER smooth motion.)
http://img129.exs.cx/img129/1251/smoothnobframes5qe.png

B-Frame madness.
http://img129.exs.cx/img129/3933/blockybframes0pp.png
If you think the pic is bad, just wait 'till you see the motion. It seriously gives you a headache. The characters go through trees! Through them. And the inconsistent quality, wow. First, there's a block-free I frame. Then, 2 block-free P frames. Then WAAM, your senses are bombarded with hideous blocking. And then, the blocks smooth out, then WAM!! double the blocks....
it's pretty clear that b-frames are not good under these (very rare) conditions.
Well, this is 320*240. Quant=31. Deblock on 2 (on 6 it almost gives me seizures to see the quality decrease-increase-decrease-increase...) 24fps. Max motion prediction on everything. 5 subpxl refinement (max). 30 refs. MAX b-frame=1 or 2 ... I forget. Rare, eh? I guess it was... Well, now it ain't! ;-)

[EDIT]
I will now address other matters.

many people have been drawn into this "Coolness of B-Frames" discussion under false pretences!

Eheh, you see, its ALL about the B-frames. There's a lot of stuff I'm concerned about regarding them. A quick recap:

1. Their coolness is off the charts (if you turn the chart upside down, heh)

2. I was merely asking why B-frames make the picture so terrible...

3. Other stuff (dynamic B-frame insertion, B-frame deblocking, B-frame renderer problems--no postfiltering of B-frames, etc)

[Manao]

Why are you complaining about blocking when you know the decoder you're using does'nt support deblocking on B-frames ? You're not happy ? Use another decoder or wait till deblocking on B-frames is implemented.

Appart from that, you should definitely try Nero's H264. B-frames are dynamic, and the decoder deblocks b-frames.

[DeathTheSheep]

Quick question... Can the Nero decoder somehow be used with AVI? Will it deblock x264 B-frames?


And yeah, I'm pointing out that B-frame deblocking is nonexistent, and that poses a huge problem without lowereing the filesize all that much.

So why is there all this hype about B-frames? They most certainly aren't nearly as "cool" as people make them out to be. Why the huge fuss over something that damages the quality?

At quantizers near 30, this is quite a problem. Many folks here didn't beleive me when I said The blocking and quality of B-frames is terrible...

Nero... The Best of The Best. Yep. But it's in MP4 format, which nothing I own supports... and it can't be edited (which I do a ton of, beleive it or not). The reason for x264 is the AVI container, man!!

That's a rockin' container. GO AVI. Wow, now I'm off topic... Baa

[DeathTheSheep]

My final word:

at lower bitrates B-frames are much better at increasing quality
False!
The results are a lot better with lower quant than those obtained with a higher B-framed quant at the same filesize...(In terms of blocking and overall quality)
True as rain, baby.

[Manao]

But will you quit falling always to the same (wrong) conclusion ? You're judging something with the wrong tools, so the results are expected.

[DeathTheSheep]

Wrong tools? ...

Oh, that explains it... :cool:

I knew B-frames were too crappy to be true in my tests...*sigh*

So how can I go about finding the right tools? I'm curious now...

[bond]

to get correct deblocking on b-frames you have to do the following:

1) avi -> raw with mpeg4ip's avi2raw tool
2) raw -> mp4 with mpeg4ip's mp4creator tool (make sure to use the latest version (~1 day old))
3) decode with nero's dshow .mp4 parser and decoder

Originally posted by SeeMoreDigital
All the samples are Mpeg4/AVC (VideoSoft H.264 Codec 2 to be more precise).nope they have been encoded with x264 (only the fourcc has been changed to VSSH)

[dragongodz]

quote:"at lower bitrates B-frames are much better at increasing quality"

False!
no not false at all. try an easy experiment. make 2 encodes with xvid with full framerate and a reasonable frame size(lets say atleast 352x288/240) and set a smallish target size(something that should average around 400kbs would be good). do 1 with Bframes and 1 without, THEN you may see Bframes do actually work.

I knew B-frames were too crappy to be true in my tests...*sigh*
your test ,as has been already said by many, is the problem. at the ridiculously low bitrate nothing looks good and there is not enough detail left for motion vectors to make any sane decisions, Bframes OR Pframes, Bframes just get screwed up worse in this example.

The main advantage of the b-frames is not the detail gain, but the better motion handling imo
and the better detail preservation gained from the better motion handling ? ;)

there are still problematic blocks, but i think it's just due to the immature b-frame ME in x264
yes i already said Bframes are the least mature part of x264 and in another thread akupenguin reccomended only using 1 Bframe for the time being because of it. so saying Bframe as a whole are bad or whatever is plain wrong of course, which i dont think DeathTheSheep is ever going to understand. so i wont bother again here, i have better things to do than waste time convincing 1 person they dont know what they are talking about. :D

[DeathTheSheep]

Bframes are the least mature part of x264
True. I confess. I'm starting to see things clearly (glaucoma clearin' up, heh, lol).

akupenguin reccomended only using 1 Bframe for the time being because of it
...Although I did only use one in my higher bitrate tests, still, yeah, I get the picture.

so saying Bframe as a whole are bad or whatever is plain wrong of course...
Well, I never actually said that they were bad as a whole. But yeah, I did complain about the blocksing and all that, so I suppose. NERO has a good deblocking postfilter, which bond explained how to use (and fairly well, too!).

is plain wrong of course...

Eheh, beleive it or not (likely not, but who beleives sheep these dayz?), I'm truly not the only person who thinks that. Many folks I know who are partially involved in video encoding push against B-frames.

which i dont think DeathTheSheep is ever going to understand

Hey, I understand now! Ease off, man! I'm second person here, too... <[ sweat bead ]> Eheh...

PS
Although I'd recommend dragongodz read the thread a bit more thoroughly... I suppose you'd see that I didn't just test at ridiculously low bitrates. I did one at "near Bearable" quality, too (to my eyes, heh, which means quantizer ~30, which is recommended for x264.)

[Dhampir]

Originally posted by DeathTheSheep
Although I'd recommend dragongodz read the thread a bit more thoroughly... I suppose you'd see that I didn't just test at ridiculously low bitrates. I did one at near perfect quality, too (to my eyes, heh, which means quantizer ~30, which is recommended for x264.)

If that's considered "perfect quality" you are again having a case of glaucoma or you are just plain blind. Even that quant 30 encode looks pretty blocky with or without b-frames. The difference being that the p-frame is being deblocked while the b-frame is not, but even with the smoothing the blocking is still quite apparent in the p-frame. If the b frame was being deblocked I'd be willing to bet that they would look almost the same. Besides comparing a P frame to a B frame is a pretty meaningless comparison considering the conditions (the p-frame is not only a lower quant but is being deblocked) which would be like comparing an I frame to a P frame and saying that P frames suck cause they don't look as good as the I frame (again a ridiculous conclusion considering the comparison).

[DeathTheSheep]

Heh, sure. To each his own, as becomes apparent in this thread... lol

Yeah, even I can admit it's far from perfect...I just tried to get something that you guys would consider "bareable" or even "watchable for short periods of time without headaches" heh. Yeah, I admit, it's pretty far from perfect. I'll edit that out! Ya gotta love computers... :D

I hereby place a request to moderate the "glaucoma" forum. :p

[Shinigami-Sama]

Originally posted by Dhampir
Here (http://www.funknmary.de/movie/) is where the samples are. They are quite hideous to watch whether they have b-frames or not.
I'm ging to agre with sheep ehre
the b frames do look like crap
but I also have very sensitves eyes
even though I had shitty glases 0_o
anyways
but hte problem is hte bitrate is to low for acurate b-frame vectors
so hte de/edncoder doesn't know what hte hell do with b-frames
and it kinda can't increase the quants anymore because you seem to have hith te limit
also
with b-frames I can only read about 1/2 hte subs
and your audio blows even for that small a file size
I wonder what happened htere
but a certain plant help glacoma sheep ;)
maybe you wer useing a bit to much medicine when encoding/watching these eh sheep? ;)

[KaiserS]

Originally posted by Shingami-Sama
I'm ging to agre with sheep ehre
the b frames do look like crap

But the P and I frames look like crap as well.

[Shinigami-Sama]

but with that being said
it means the b-frames will look worse
seeing as how they;re hte more or les byproduct of hte p and i frames
there isn;t enough data left to justify useing b-frames at that low of a bitrate

[SeeMoreDigital]

I think this thread has run its course and should be closed now... It's doing more harm than good!

Both RadicalEd (http://forum.doom9.org/showthread.php?s=&postid=597725#post597725) and Skal (http://forum.doom9.org/showthread.php?s=&postid=597918#post597918) have pointed out why the original posters B-VOP comments are based on flawed assumptions!

In essence... DeathTheSheep's B-frames look poor because his I and P "reference" frames were poor to begin with!

[Elias]

Originally posted by DeathTheSheep
Yeah, I've heard all the hype. I see it written about in posts all the time. Never a day does pass without questions pertaining in some form or another to B-Frames ("When are B-Frames gunna be enabled for AVC?!!!!"). But now I must ask, what the heck is up with B-frames anyway?

I heard they are a form of bidirectional frame encoding/rendering. At this, I scratched my head long and hard and almost pulled a "pancake bunny." So what?!

B-Frames are complicated, they take long to encode, they are BLOCKY as HECK, and they increase filesize. Need I upload a sample with and without B-Frames fer y'all to see? Why don't people stick to the IPPPPPPPIPIPPPPPPPPPP... method? Complexity? If so, I don't see it.

So what is all this B-Frame craziness? What use to they serve? Or are they only useful at collosal bitrates (yeah, I'm livin the >56kbps road)? NeeheeharharharHAR.... No, seriously,
Inform Da Sheep Afore He A-Kills Hisself...BAAAa Wow, was that English? I'm impressed, you should become a literature writer. As for B-Frames, they're good. The image becomes somewhat softer, as (opposed to sharper) but you loose lots of macroblocks. So, conclusion is to not use B-Frames with higher bitrates. Only with low bitrates is it to be used. Besides, it degrades the compatibility for the MPEG-4 file. I've completely stopped using B-Frames.

[Tommy Carrot]

Originally posted by Elias
As for B-Frames, they're good. The image becomes somewhat softer, as (opposed to sharper) but you loose lots of macroblocks. So, conclusion is to not use B-Frames with higher bitrates. Only with low bitrates is it to be used. In my opinion b-frames are always beneficial, except when the codec reaches the maximum quality (but this is only problem with mpeg ASP, as AVC becomes saturated at MUCH higher bitrate), and - as DeathTheSheep's example showed - at ridiculously low bitrates, where the reference frames are already useless. The softening effect is not necessary, it's quite the opposite, the bitrate saving of b-frames helps to preserve even more details.

[Elias]

Originally posted by Tommy Carrot
In my opinion b-frames are always beneficial, except when the codec reaches the maximum quality (but this is only problem with mpeg ASP, as AVC becomes saturated at MUCH higher bitrate), and - as DeathTheSheep's example showed - at ridiculously low bitrates, where the reference frames are already useless. When I said low bitrates, I meant like 1024 kbit/s etc. using very very very low bitrates... it doesn't matter what you use, it will look shitty either way. Honestly, I don't see the point with B-Frames at bitrates such as 3 mbit and up. It'll only make the video not playable on some DVD standalones and... well, Quicktime :) Who cares about Quicktime anyway. Hehe, seriously though, there are lots of software players that can't handle B-Frames/GMC etc.

[yaz]

Originally posted by Elias
... seriously though, there are lots of software players that can't handle B-Frames/GMC etc. wouv ... just point me only one :) anyway, handling b-frames is not a player issue when sw environment is considerded but a codec one. hw players are another part of this prob, of course.

however (just my simpleton approach) why do u think so many ppl of brilliant minds & skills would put so much effort on implementing b-(s-, n-)frames in their codecs if it(they) were such useless a/o harmful as u state ? ever thought of that ?

the bests
y

[Elias]

Originally posted by yaz
wouv ... just point me only one :)
Philips MPEG-4 Player.
Originally posted by yaz
however (just my simpleton approach) why do u think so many ppl of brilliant minds & skills would put so much effort on implementing b-(s-, n-)frames in their codecs if it(they) were such useless a/o harmful as u state ? ever thought of that ?

Originally posted by Elias
As for B-Frames, they're good. The image becomes somewhat softer, as (opposed to sharper) but you loose lots of macroblocks. I said it was good, not harmful. I rest my case.

[KaiserS]

Originally posted by Elias
[B]Philips MPEG-4 Player.

I have the DVP-642 and it handles my XviD encodes with 2 consecutive b-frames just fine.

[Elias]

Originally posted by KaiserS
I have the DVP-642 and it handles my XviD encodes with 2 consecutive b-frames just fine. I was talking about the software player.

[KaiserS]

Originally posted by Elias
I was talking about the software player.

Oh, my bad.

[Elias]

Originally posted by KaiserS
Oh, my bad. No problem :)

[rawr]

I second the 'use snow' call a while ago. Sure, it may not look much like the source at ultralow bitrates, but it's certainly pretty. :D

rawr.

[DeathTheSheep]

Page 3, 3rd post from the bottom. It's a much better quality example of the point I was making. No blocks at all, very visible picture, crystal clear on all P-frames. But if you look at the B-frame version, it is visibly worse. And this isn't a glaucoma picture like the horrible quality thing I showed at the top of page 3. Disregard the bad quality ones for download, and look at the good quality one. (I had it up for download in super high quality, but I was forced to remove it from angelfire (not enough room).)

Speaking of glaucoma, anyone know what kind of plant cures it?

Mindless prattle ensues; spare yourselves boredom and confusion by deigning not to heed it...

BaaAAAa, I'd LOVE to be a novelist. Problem is, who would buy my sheeply satires? (HAH, look, what a joke, I misspelled it...and that TOO!! NEHEHE, ok I'll shut up now... I wonder how long the longest post in history was... What would happen if France sunk to the bottom of the sea...FrAtlantis...What if ffdshow cures my glaucoma...wait i dont have glaucoma....wt*..wouldn't the world be cool if anime was real...no, not RealVideo...altho that would be nice too...)

[Shinigami-Sama]

Originally posted by DeathTheSheep

Speaking of glaucoma, anyone know what kind of plant cures it?
locoweed is cure mate ;)
best is avable in none other than my home province of B.C..:cool:

Originally posted by DeathTheSheep
Page 3, 3rd post from the bottom. It's a much better quality example of the point I was making. No blocks at all, very visible picture, crystal clear on all P-frames. But if you look at the B-frame version, it is visibly worse. And this isn't a glaucoma picture like the horrible quality thing I showed at the top of page 3. Disregard the bad quality ones for download, and look at the good quality one. (I had it up for download in super high quality, but I was forced to remove it from angelfire (not enough room).)

yeah anglefire sucks..
I can copy/paste hte link ot hte homepage
and keep hitting enter and every few times I get a pornsite load up -_-
and a bad one at that
and by 'good'qual you mean hte non-2meg ones?

[Sharktooth]

Ok, wait...
B frames were never meant to look like P or I frames. They are there to spare bits so the codec can redistribute them for a better overall quality.
They were intended to look worse than P and I... but as long as you keep the max cons. b-frames value to 1 or 2, during playback, your eyes won't be able to spot the difference (that's the theory behind b-frames...).
A frame by frame comparison will show the difference but that's a nonsense coz you dont watch movies frame by frame...

[Mug Funky]

well, actually, b-frames at the same quantizer is the rest of the video i imagine would look very much the same (this wouldn't apply to very high quants though). the trick is that b-frames are able to deliver comparable quality at a higher quantizer than p and i-frames.

the reason we have no more than around 2 consecutive b-frames is because they don't predict from other b-frames, but rather the nearest p or i frame. this means the reference frames are further apart, and thus the motion-compensation becomes less useful. this is where DeathTheSheep's problems come in - he's decimated the frame-rate, which does practically the same thing as increasing consecutive b-frames (except the overall motion is jerkier). you have the combination of slow playback giving the eyes more time to catch badness, and poor motion-compensation because the interframe differences are much higher.

k... hope that makes sense. i'm asleep at the keyboard here :)

[dragongodz]

is there an echo ? or is that a scratched record that keeps repeating ? funny i can hear the same things being repeated over and over and over and over......

leaves just one thing to say really.

DIE THREAD. JUST BLOODY DIE ALREADY. WHY THE HELL WONT YOU UP AND CARK IT ALREADY ? :devil:

[DeathTheSheep]

DIE THREAD. JUST BLOODY DIE ALREADY.

We hear ya, mate.

If you hear the same things, something's gone wrong... People aren't looking at page 3, 3rd post from the bottom.


No, framerate isn't decimated. 23.976fps. That post (3rd page, 3rd from bottom) will cure all. Even better than locoweed.

That's right, 3rd page, 3rd post from the bottom is a different test--not the one that's 2mb.

So load up on your locoweed guys, and head on over to take a peek at the post everybody missed.

One last time, the post that everybody missed is on the 3rd page, and it't the 3rd post from the bottom.

Then this thread will die. I'll die it myself. With locoweed. *cough*.

[ChronoCross]

Originally posted by DeathTheSheep
Eheh, I think I'll pass. Let me work one up for you, man! And at a lower quant. Baa! :p

Ah, here goes.

Bframes: (not same frame according to VDub, because B-frames through off frame count, another example of B-frame coolness hehe)

As you can see, b-frames give terrible blocking while movement is taking place, and I can't tell what the heck is going on. How many characters do you see? Maybe no the best example, but you get the point. Sample 1, frame 58 (B) or 55 (P):
http://img49.exs.cx/img49/1268/bf0jl.jpg

NO BF
While still pretty blurry (as i said, not the best example), it's a heck of a lot worse. I'll try higher br later. How many characters are there? Fundemental estimation difficulties with low framerate.
http://img49.exs.cx/img49/6277/nobf6bb.jpg

Convinced?

You should be shot for ruining a scene from naruto. Did you try reencoding a already horrible codded fansub rip from Dattebayo? If so you are #1 working with a bad source...trying to recode a poorly done xvid into a smaller xvid will only make it worse. either that or it was a divx raw provided by saiyaman.

B-frames in 95% of cases, especially with anime will improve the quality of encodes. the common rule to follow when you are encoding anime is 175MB per 23.5 minutes of video, even xvid at defaults should handle this quite nicely. also filtering can have a big effect on the quality. Most people are in too big of a hurry to apply proper filtering of TV rips. TV rips most consistently when captured from a video capture card are oversharpened which takes up valuable bitrate so you should smooth it down slightly. Additionally you should always return a 120fps encode to 29.997 or 24 fps in order to save space because there will be almost no lack of smoothness if it is decimated correctly, another thing that a majority of people lack. If you feel like bframes are still totally screwing the quality then you should lower the sensetivity to reduce the number used. But saying that bframes lower the quality considerably is totally bogus. in most cases it will even increase the quality tremendously.

btw that clip is of chouji, shikamaru, Naruto and Neji Chasing the sound 4 through the forest to rescue sasuke.....

[Shinigami-Sama]

umm
those are from a very small source
and naruto isn't all that great now anyways it aws but...
anyways
bt;s qual isn'tthat bad better tha nsome of hte groups
and saiyaman blows to start with
that was db because it;s subed hte same way
those are like a quant of 45 I think
and untill you said it
I did;nt see anything in that pic
Sheep is using bitrates so low
that you can't get any motion vectors out of hte p&i frames to make bframes useable
like said in pretty much every 3rd post...

[DeathTheSheep]

Originally posted by DeathTheSheep

I revised my tests and now use much lower quantizers and full framerate (24fps vs. 7-8fps) and a less brutal quantizer (31 instead of 45). (Like proposed intermediate, kinda).

The results? The B-frame encoded clips are terrible. TERRIBLE. The motion is so horrendous, and the quality is EXTEREMELY inconsistent.

Screen of EXACT SAME FRAME (same thing happens for just about every frame, too, not just this one. I'd say 1/3 or at max 1/6 frames, and even worse, some of them.

Screen:
NO DANG B-FRAME MADNESS!! Smooth pic (AND SUPER smooth motion.)
http://img129.exs.cx/img129/1251/smoothnobframes5qe.png

B-Frame madness.
http://img129.exs.cx/img129/3933/blockybframes0pp.png
If you think the pic is bad, just wait 'till you see the motion. It seriously gives you a headache. The characters go through trees! Through them. And the inconsistent quality, wow. First, there's a block-free I frame. Then, 2 block-free P frames. Then WAAM, your senses are bombarded with hideous blocking. And then, the blocks smooth out, then WAM!! double the blocks....

Well, this is 320*240. Quant=31. Deblock on 2 (on 6 it almost gives me seizures to see the quality decrease-increase-decrease-increase...) 24fps. Max motion prediction on everything. 5 subpxl refinement (max). 30 refs. MAX b-frame=1 or 2 ... I forget.


NOBODY CAN SEE THIS?!! :scared: :scared: Wow, everyone goes back to the crappy test, and everyone overlooks this one. Quant about 30, which is the recommended quant for anime. How on Earth can nobody not see this? Seriously, I'm just pointing this fact out, but it's kinda wierd. Maybe it only shows up on my computer. Aw, heck, I wish I could just delete the old one with the horrid 45 quant. NONONO!! Now everyone thinks I'm a jerk (I'm a SHEEP. A locoweed-ed SHEEEEP) because everyone thinks I'm going crazy with the low bitrates. And good folks like dragongodz are compelled to adopt expressions of confusion and frusteration and eventually anger at the sheep who JUST WONT GET IT... but it's not really ME who won't get it, because everyone skipped the most crucial post in the entire thread, assuming instead that good ol' Sheep's tests are WACK or borked (whatever "borked" means, jeez, it's not even in the dictionary)..
Ah, whatever. Someone autta slaughter the sheep--I mean, realize the sheep's message and leave without shearing the sheep's dignity... aw it's 11:30... Gotta do homework...
And what's wrong with Naruto? It's the best anime in the universe... It just keeps getting better!! Remember the old stuff with Haku and Zabuza? And then Gaara? And finally, Sasuke as evil... Man, it can't get much better.
And with x264 (WITHOUT B-FRAMES) I can compress an episode to 20MB (AAC-HE at 40khz, 31quant)...,

[Shinigami-Sama]

if you want us to use this as a test
post damed clips of it
unles that now wrong seeing as how it;s licensed

naruto got raly bad the last 40eps
and it jst stated to dig itself out of hte hole it dug
and I endoce anime at like err what quant I forget at like 1GB per 1.5hours so w/e mate you and your 20megs and ep

[DeathTheSheep]

Originally posted by Shingami-Sama
if you want us to use this as a test
post damed clips of it


Ah, I would, BAaa. The problem is, I have nowhere to host them. BTW, I believe short clips are permissible for demonstrational purposes, as long as the content matter as a whole isn't revealed...

So anywhere?

Have a good life. Death is around the corner. DeathTheSheep, that is. ;-)

[ChronoCross]

Ok you need to provide info about your source. because you might actually be one of the crappiest encoders alive if your bframes are that crappy, sorry for the language but this guy is totally off base with his encoding methods.

I need the following source info
Framerate: 120(NTSC/FILM lowest common Blend), 30(NTSC), or 24(FILM)
DeInterlaced by the capturer or by the encoder(you)
Capture codec: xvid or divx
Complete AVS
Complete Xvid settings.

It seems to me you are just doing stuff to purposely make bframes look really bad. I have done hundreds of tests and never run into the problems you seem to be having. Also are you using the xvid decoder or something else.

[SeeMoreDigital]

Somebody... close this thread... please!