x262 Development Thread

[kieranrk]

ifb and I are writing x262, an mpeg-2 encoder building on the best-in-class features of x264

Git tree (more likely to be broken than working at any given time):

http://github.com/kierank/x262

Intra working. Inter in development.

[ifb]

Now I need to finish quant. :)

[shon3i]

I will send you DVD specs, as soon i remember to look at workplace ;)

[Mug Funky]

perfect! now all you need is to fill those blocks up with pixels!

:)

seriously looking forward to this one. who said mpeg-2 is dead? CCE is still selling and DTV is looking as crap as ever, so there's always going to be room to stir things up a bit.

best of luck!

[aegisofrime]

Interesting project! I don't think DVDs are going away anytime soon (The install base is too huge!), so somebody will find a use for this for a long time yet! All the best!

[Gromozeka]

:( But where compile program for testing?

[ifb]

:( But where compile program for testing?There's nothing to test yet, unless you want your encodes to look like the above. Follow one of the guides for compiling x264, but clone the x262 github repository instead of official x264. Patches welcome.

Quant is done, but mostly untested until AC coefficient VLCs are written to the bitstream. Then we can encode more than an 8x8 blockfest.

[Lyris]

who said mpeg-2 is dead?Hear hear. Honestly, I get a ton of satisfaction from producing DVDs with Cinema Craft, because the quality dumps all over what's seen on most commercial discs when it's used carefully. The satisfaction from doing MPEG-2 right is huge because it's not so easy.

So I look forward to seeing what this can do!

[turok]

so i notice there is no update on this topic... how is dev. going for this atm?

[kieranrk]

ifb finished off intra and we're moving on to inter.

[Mug Funky]

nice! so the blocks are filled with details now?

just to illuminate things here, how much needs to be done to squeeze the x264 elephant into the mpeg-2 morris mini?

[7ekno]

Is the VAQ framework also going to be featured ?!?

Tek

[jfcarbel]

Is this reason (http://forum.doom9.org/showpost.php?p=1462825&postcount=17) why you might be developing this project? :)

[kieranrk]

Is this reason (http://forum.doom9.org/showpost.php?p=1462825&postcount=17) why you might be developing this project? :)

Not at all. That reason doesn't even make much sense.

The Open Source Broadcast Encoder is the main reason x262 is being written.

[Biggiesized]

So you're targeting the broadcast space, not DVDs? Or both? Very interesting now.

[kolak]

Not at all. That reason doesn't even make much sense.

The Open Source Broadcast Encoder is the main reason x262 is being written.

And later introduce commercial license as with x264 :)


Andrew

[kieranrk]

So you're targeting the broadcast space, not DVDs?

Personally I don't care much for DVDs. I don't think ifb does either.

[hank315]

Personally I don't care much for DVDs. I don't think ifb does either.
But will it be possible to create DVD compliant encodes with x262?

[kieranrk]

But will it be possible to create DVD compliant encodes with x262?

Very likely yes.

[hank315]

OK, otherwise IMHO it will be useless.
Is there a time scheme when it will be finished?

[kieranrk]

OK, otherwise IMHO it will be useless.

Not for the people wanting to use it for ATSC MPEG-2 transmissions it won't :p

[nakTT]

Any info regarding the quality/filesize ratio compared to x264?

[Mug Funky]

you could look at the first post...

this is very much not ready for public consumption.

my guess, seeing the state of the art of current mpeg-2 and current h.264, this would be around same quality at 2-2.5x the bitrate of x264?

if we can get interlaced video to look good at less than 4mbps, i'd be screaming in the streets to crowds of uninterested and confused people. i suspect this may be the case.

[kieranrk]

ifb has gotten P-frames working.

[Biggiesized]

Any new updates?

[ifb]

Any new updates?I've been busy (plus a little lazy) and kierank has been working on OBE a lot, so there isn't that much x262 news.

I do have B frames nearly working in my local tree, however. Patches welcome if anyone wants to take on the TODO (http://github.com/kierank/x262/wiki/TODO) list.

[Mug Funky]

in case anyone's after an update of sorts...

first up, this is a fantastic project - just thought i'd add some encouragement to kierank and ifb's efforts on this.

i followed an x264 compiling guide and git'ed from x262's repo. i'm a complete newb at this, but it all worked smashingly in windows.

here's a rundown of what i can see so far:

- avs, raw and y4m support only (unless i'm doing it wrong).
- fullpel only for now (set subme to 0), as x264's qpel seems to get mapped to hpel and thus the blocks are moved twice as far as they should be. i imagine this is a largish undertaking on account of h.264 having different filtering etc for qpel than mpeg-2's hpel.

- crf values are comlpetely unrelated to those that x264 uses - try much lower values
- output streams are not compatible with DVD authoring programs (spruce gives me a "temporal references out of order" error).

- quality is surprisingly good, with the occasional blocky glitch on movement. the encoder seems to bias toward making grainy noise rather than flat blocks, which is good news for film lovers, especially when hpel gets implemented. by "surprisingly good", i was expecting something like the screenshot at the start of this thread. it's still not really watchable...

- no interlace as yet, but there is alternate scan.

tl;dr: this is not ready for general consumption yet.

i wont release my compile for this reason - i can't be sure i didn't do anything wrong in the compile (it's my first time), and if unofficial binaries start floating around at this early stage, the encoder might get an undeserved reputation before it gets a chance to be finished. i'm testing more out of curiosity than anything serious.

this is really promising...

[edit]

i just tried it with the mpeg matrix and it looks a lot better. about right for something that's crippled with fullpel. this has really come a long way in a short time!

[Sagittaire]

Really interessing project because x264 is really advanced codec (psy, RDO, RC ...) and portability for x262 will be potentially really promising ...

[CruNcher]

yup not only but if you look @ XviD i wonder what could have been reached their with x264 as its base (especially the asm and multithread optimization) :) Darks VAQ port is nice but when x262 is really successful and can show that the base of x264 works efficiently their then why shouldn't it be more efficient then the current base XviD code (RC,RD) and can we dream about a x263 then ? ;)

[Mr VacBob]

It wouldn't be difficult to make an x263 from a complete x262. That said, x264 --tune fastdecode recovers about half the decode time from normal settings and is still much more efficient than MPEG4 ASP.

[plonk420]

what switches are you all trying?

[iwod]

It seems x262 development has stopped? ( Although it is still included the x264 mailing list )

[kieranrk]

We have been busy on other things. Having been accepted to speak at IBC about open source broadcast I (and likely ifb) will have even less time.

[plonk420]

what switches are you guys using? all i've tried so far is

x262 --crf 8 --mpeg2 --subme 0 --fps 24 -o output.m2v input.avs

(adjusting the CRF)

anything else you guys are trying?


edit: thanks for this awesome project, kieranrk, ifb, and any anyone else contributing!

edit2: interestingly, kkrunchy and crinkler don't like it. upx does, and slightly amazingly "best compression" mode doesn't trigger any antiviruses

[kieranrk]

There is a tender out to add interlaced support to x262: http://mailman.videolan.org/pipermail/x264-devel/2011-October/008887.html

[nautilus7]

Where i can find x262 binaries?

[pandy]

There is a tender out to add interlaced support to x262: http://mailman.videolan.org/pipermail/x264-devel/2011-October/008887.html



But MPEG-2 is not able to have MBAF...

[MatLz]

Where i can find x262 binaries?

Here (http://hotfile.com/dl/133462733/16daece/x262.zip.html) is one.
However, crf seems to be broken ? Use -q instead.

[kieranrk]

But MPEG-2 is not able to have MBAF...

not true. MPEG-2 frame pictures can switch between field and frame modes.

[mp3dom]

Isn't it more similar to PAFF then?
Anyway, while it is supported by the MPEG-2 standard, it isn't well supported by a good amount of standalone players (they made visible judder when the switch happens). I'm referring to the picture structure (Field/Frame) that the encoder change on (I think) GOP basis. Don't know if you're referring to the same. GV ProCoder is one of the few encoder that support this feature.

[kieranrk]

No it is not like PAFF. PAFF is also allowed (field mode pictures).

[drmpeg]

Here's what MBAFF looks like in MPEG-2.

An interlaced frame (luma only).

http://www.w6rz.net/bluma.png

The macroblock types in a B-frame. blue = forward, yellow = backward, pink = bi-directional, dot = quant change, horizontal line = field DCT.

http://www.w6rz.net/bmtype.png

The motion vectors. Horizontal line = field vectors.

http://www.w6rz.net/bvectors.png

Ron

[ifb]

what switches are you guys using? all i've tried so far is

x262 --crf 8 --mpeg2 --subme 0 --fps 24 -o output.m2v input.avs

(adjusting the CRF)

anything else you guys are trying?

For NTSC DVD (untested in Scenarist, etc.):
x262 --mpeg2 --preset placebo --tune film --open-gop normal --fps 24000/1001 --pulldown 32 --sar 16:9 --keyint 14 --bframes 2 --vbv-maxrate 9800 --vbv-bufsize 1835 --crf 1.5 -o output.m2v input.avs
Actually DAR is broken. I'll take a look why later (it was working).
Here (http://hotfile.com/dl/133462733/16daece/x262.zip.html) is one.
However, crf seems to be broken ?Ratecontrol isn't optimal, but I don't think CRF is broken. The scale, however, is different from H.264 and you'll need a much lower value.
Use -q instead.Unless you're testing, I wouldn't recommend that. Constant quantizer is pretty useless.

[MatLz]

I meant this kind of thinghttp://data.imagup.com/11/1134819774.png (http://www.imagup.com/data/1134819775.html)


In case that can help, I did upload the files here (http://hotfile.com/dl/133939237/3b5b7d5/x262_all_files.7z.html).

But I maybe did it wrong...

[ifb]

I meant this kind of thing <image>

In case that can help, I did upload the files here (http://hotfile.com/dl/133939237/3b5b7d5/x262_all_files.7z.html).

But I maybe did it wrong...From the TODO (https://github.com/kierank/x262/wiki/TODO), certain subme levels are broken, so don't use them.

[ifb]

Actually DAR is broken. I'll take a look why later (it was working).Setting DAR is broken when using the internal resize filter (resize assumes SAR).

[ifb]

Just to say I've tried it, files can import in Encore CS5.

Parkjoy 25p (http://www.mediafire.com/?5auu918z3hzb47n)

That's a 10 second clip, so YMMV.
x264 park_joy_1080p.avs -o parkjoy_paldvd.m2v --mpeg2 --preset placebo --tune film --open-gop normal --keyint 12 --bframes 2
--vbv-maxrate 9400 --vbv-bufsize 1835 --crf 1 --fake-interlaced --sar 16:9 --colorprim smpte170m --colormatrix smpte170m --transfer smpte170m

ffvideosource("park_joy_1080p.mkv") #lossless, from .y4m
selecteven()
lanczosresize(720,576)
colormatrix(mode="Rec.709->Rec.601")

[pandy]

so picture can have combination of interlace and progressive macroblocks? ie MBAFF

[ifb]

so picture can have combination of interlace and progressive macroblocks? ie MBAFFCorrect. Each macroblock in a frame picture can use either field, frame, or dual-prime prediction. Macroblocks in field pictures can use either field, 16x8, or dual-prime prediction.

[pandy]

Ok - bit weird but all comparison between H.264 (and other codecs) assume superiority of H.264 due MBAFF which accordingly to various descriptions is unique for H.264