x264 Anime Encoding... Very Low Bitrate test...

[Quarkboy]

As an experiment I encoded one of my fansub group's releases shooting for 85 MB (1/2 the "standard" size for 30 minutes eps) total filesize, using x264 rev295 CLI and vorbis for the audio.

There's a torrent for it here (http://www.arienai.com/bt/torrents/%5BArienai%5D_Pretty_Cure_-_35_%5BExperimental_Encode_h.264_Vorbis%5D.mkv.torrent)

If you'd like to compare it with a 233 MB Xvid encode, you can find a torrent for that easily enough.

I'll take down the torrent in a couple of days. This is encoded off the identicle avs as the 233 MB Xvid encode I already released, so if you'd like to compare, feel free to download both.

Data about the encode: 85.2 MB: Video 73 MB, at 420 Kbps, H.264 rev295 CLI Audio: 12.1 MB Ogg Vorbis at 80 Kbps. It's High profile AVC, except it doesn't use CQM, so it should be playable with the CCCP or a recent version of ffdshow. Source is DVD, IVTC'ed with tritical's tfm, tdecimate, very slightly filtered. 3-pass, 8 reference frames, RDO, deblocking at 2 and 2, bitrate variability 4, 4 bframes, pyramid, adaptive, max quant delta 8, multi-hexagon. Other than that, settings are default.
Encode took about 8 hours.

My opinion on quality: Lines are a big jagged looking in higher motion scenes. One or two places with blurred color blocks in hair, etc. Probably could have benefited from zoning the opening/ending. Overall, slightly better quality than a 175 MB Xvid encode, but not as good as the 233 MB.

Comments are not only welcome, they are REQUIRED.

[Quarkboy]

bitrate variability 4...

You know, I was highly confused by that, and you're right... Then why is the default value 1.00?

I though the scale was somehow different than the vfw version or something, so that 1 meant 10% or something... But if it's the same then, that would explain some things :). Hell, still looks pretty damn good. When I was experimenting with the vfw version, I would boost the variabitily way up into the 80s...

[hpn]

Let's hope your torrent is for educational and comparison purposes only. Not much to comment on the video. It's been proven many times that x264 is very good on low bitrates and delivers razor-sharp encode on slow and especially still anime sequences, and has some problems with very fast motion going down to quantizer 38 in your case. You may want to play with some different bitrate control settings to try to make the fastest sequences look better . It's also better if the subtitles are not encoded in the video, but muxed separately. Here are some shots:
still sequence
http://img367.imageshack.us/img367/9449/purestill3pw.jpg
slow sequence
http://img367.imageshack.us/img367/1983/pureslow9ec.jpg
fast sequence
http://img367.imageshack.us/img367/6436/purefast1wd.jpg

[Quarkboy]

Let's hope your torrent is for educational and comparison purposes only. Not much to comment on the video. It's been proven many times that x264 is very good on low bitrates and delivers razor-sharp encode on slow and especially still anime sequences, and has some problems with very fast motion going down to quantizer 38 in your case. You may want to play with some different bitrate control settings to try to make the fastest sequences look better . It's also better if the subtitles are not encoded in the video, but muxed separately.

Yes, the torrent is for educational and comparison purposes only :) If you want something to watch and enjoy, you can look elsewhere.

Now, some questions (because I haven't found any decent documentation for the CLI options and I'm still curious about what some of them do):

In the rate control section, you have VBV Buffer Size, VBV Maximum Bitrate, VBV Initial Buffer, Bitrate Variance, Quantizer Compression, Temp. Blur of est. Frame complexity, and Temp. blur of Quant after CC.

What units are the VBV Buffer size in? Actually, what the hell IS the VBV Buffer size? So far I've only ever left it blank. Same for the VBV maximum bitrate. The VBV Initial Buffer ranges from 0-1.0, what does that set, exactly?
Bitrate variance I think I understand... it's in 100% of average bitrate, correct?
Quantizer compression probably lowers the maximum quant and raises the minium quant...
Temp. Blur of Frame complexity helps keep quants from changing too fast, anf temp. blur of quant after CC.. does the same thing after... Curve compression? That's a guess.

quant compression goes from 0-1, but the temp blur is an arb. int (or half int).

Frankly, I'm just looking for a more wordy description of what some of these do, without trying to look at the source code. :)

[hpn]

For most of the options read the x264 quide posted by DeathTheSheep:
http://forum.doom9.org/showthread.php?t=98247&page=1&pp=20

DeathTheSheep made some mistakes in his conclusions, so also read the whole thread following the guide and especially Bond's and akupenguin's comments, giving the akupenguin's posts top priority, as he is the author of x264 (along with some other people) and the only one around who really knows what's happening "behind the scenes" :)

[Quarkboy]

ACtually, already read that thread... it gives lots of info, sure, but mainly geared toward the vfw interface. There are still a number of options in the CLI version (or megui version) I'm not sure of exactly how they work or what the ranges correspond to that isn't covered in that thread.

In leiu of that, a general question: Which is better for making sure high motion scenes don't get too high quants in low bitrate encodes.... setting a lower Max Quant or upping bitrate variability/lowering curve compression? What about increasing the quant step to 8 instead of 4? All things things would help, I'd think, but they also have different side effects...

[MeteorRain]

i compressed a video (infact kamichu ep06 hdtv version(source come from 8e3@share)), bicubic resize to 848*480, and compress it using x264.

i just compressed it to 58MB (video length 24min) while the video quality is still perfect good.

i just keep the ipratio and pbratio at 1.0 so the quality is constant, and encode at about CQ qr22 (Wow extremely high compress ratio:o)

[DigitalDeviant]

Thanks for the episodes, glad someone is subbing the series (and TLB) :thanks: I got the x264 version last night just to see. Impressive compression but I'm burning off the XviD version.

I've been running similar tests using Honey & Clover and Seikai no Senki III (using some light noise removal and limitedsharpen,) both with good results. SnS III I've managed to encode a 764x432 version with 5.1AC3 at about 150mb or less and still looks very good aside from the blocks in certain colors that don't seem to go away even at higher bitrates, but I'm testing some cqm's to see if I can fix that.

As it stands for fansubs, XviD @ 233mb for a 24min episode from a DVD source still looks a little better to me, but I don't think I'll be saying that much longer.

[ggab]

with 500kbps for video and 64kbps for audio, you will get a 24min episode in ~99mb file (7 ep. in one cd-r)
have a look at Sirber's RealAnime, it has nice defaults x264 settings and great quality with HE-aac in 64kbps