x264 development

[LigH]

In my opinion, the SAR option works wrong.

I used the following command line:

--bitrate 1000 --min-keyint 50 --ref 6 --subme 6 --bframes 3 --weightb --b-pyramid --analyse all --qpmin 1 --ratetol 4.0 --merange 64 --me umh --sar 16:9 --progress --threads 1

The result:

ffdshow 2005-07-03 reports an AR of 20/9.

mplayer 2005-06-27 reports a movie AR of 2.22:1.

All players and filters (Ateme too) resize from 720x576 to 1280x576.

[Sharktooth]

Some doom9.it users reported that problem too...
the weird thing is i made a lot of anamorphic encodes and didnt notice it.
i'll make a new encode to check.

[DeeGee]

Works fine here. At least when I use the aspect ratios told here.

And here are the settings you'll need for both PAL and NTSC 4:3 and 16:9 DAR (which are based on PAR): -

Required AR Custom DAR(PAR) Setting
4:3 PAL 64:60 (or 16:15)
16:9 PAL 64:45
4:3 NTSC 64:72 (or 8:9)
16:9 NTSC 64:54 (or 32:27)

I simply use those values as imputs for the --sar setting as these aspect ratios with their sar, dar and par make me dizzy
I'd need quite exact explanation on which means what and how to calculate them.

[LigH]

O.k. - so must be my mistake, I probably read it as "source AR" or so...

If the sample=pixel AR is used here, I'll try again with 1024:704 = 16:11 (almost IRU-R BT.601 compliant). Here I would expect a width of 720*16/11 (~ 16) = 1048 pixels.

[Manao]

LigH : your results are those expected : SAR means Sample Aspect Ratio : it's the AR of a pixel. Now, the Aspect Ratio is somethings different : it's the playback width / playback height. Since you encoded a video whose ratio width / height is 5:4, and since you set up a SAR of 16:9, you get an AR of 16:9 * 5:4 = 20:9, ie, what the playback filters are reporting.

[LigH]

Yes, must be right: 720*16/9 = 1280, and that's what I got. My mistake.

[Japhsoncross]

i did some tests for a few days on x264 and nd mp.
i captured the video from the window while i was playing the emu(emulator) 384*224(machine resolution)@30fps, and the game is Street Fighter Zero 3, i think this kind of material is absolutely clean, 'cause the background and character moves without details changing. i encoded it with both x264 v270vfw and nero recode @650kbps and 750kbps. and my decoder is ffdshow050619, and i turn the visualizations fuction of ffdshow on, with displaying the motion vectors. i found that on most occasions, nd mp's motion vectors seem more correct than x264's according to the video.

settings:
targat bitrate 750kbps
x264: no loop filter(deblock), max ref 5, minqp 1, b frame reduction 0, max 3 b-frames, use as ref, adaptive, bias 0, 8*8DCT 4*4intra, chroma me, RDO, UMH , me range 32, direct mode temporal.
nd mp, -512 - 512, 5 ref, no deblocking

see the images attached:
ND MP@750kbps

x264 v270@750kbps

[FredThompson]

The sources link is dead. Given it's summer break :P, would someone pease mirror these?

Japhsoncross: That doesn't look right at all. Something's amiss.

FredThompson: It's only really a 'summer break' because akupenguin is away. I'm fairly sure SharkTooth is still around and anyway you can find out how to get the source code on http://developers.videolan.org/x264.html .

[leowai]

Originally Posted by Sharktooth

Some doom9.it users reported that problem too...
the weird thing is i made a lot of anamorphic encodes and didnt notice it.
i'll make a new encode to check.

Me too. Just realise that days of conversion wasted, but we learned from mistakes.

Originally Posted by LigH

O.k. - so must be my mistake, I probably read it as "source AR" or so...

Since there are confliction caused, will it be good to name the parameter as PAR (Pixel Aspect Ratio, which used in the link below) rather than SAR (Sample Aspect Ratio)? Sample also not clear enough for me. Sample = Source (i.e. original source)? Sample = Input Video source for encoding?

Originally Posted by DeeGee

Works fine here. At least when I use the aspect ratios told here.
I simply use those values as imputs for the --sar setting as these aspect ratios with their sar, dar and par make me dizzy
I'd need quite exact explanation on which means what and how to calculate them.

I think following link is useful to you. It provides some information about this matter:
http://www.3ivx.com/support/par.html
Just learn that: It's NOT neccessary for the pixels a video to be sqaure (i.e. width-to-height ratio of 1:1)!

[Manao]

Japhsoncross : the picture you chose is a bframe, isn't it ? some version of ffdshow are buggy when displaying motion vectors on bframe.

Leowai : the standard calls explicitely that parameter SAR, not PAR.

[LigH]

From ISO 13818-2 (6.3.3: Sequence header), MPEG-2 does it in a similar way: Allowed aspect ratios for MPEG-2 video are

- 1:1 SAR
- 4:3 DAR
- 16:9 DAR
- 2.21 DAR

and SAR = DAR * width/height

So the same must obviously be true for MPEG-4 video.

[Manao]

> SAR = DAR * width/height

Hum, no. SAR * width / height = AR ( or DAR )

[LigH]

In this document, they use an inverted DAR. 3:4, 9:16, 1:2.21 - that's why...

I hate such kind of "un-common" specification.

[Sharktooth]

Originally Posted by FredThompson

The sources link is dead. Given it's summer break :P, would someone pease mirror these?

Link to the source files is fixed... (sorry, didnt notice it)

[namchik]

vfw dll was packed into CLI version ??

[Rash]

Yes, it was.

[leowai]

Originally Posted by Manao

Leowai : the standard calls explicitely that parameter SAR, not PAR.

Thanks for correcting my wrong concept.
I see the update of vfw build from sharktooh too.

@namchik,

I think the *CLI* only consists of the client executable. If you want vfw support in VirtualDub, you need to download the installer instead.
x264 VFW Revision 273: http://www.webalice.it/f.corriga/x26...rev273_mmx.exe

[Sharktooth]

Sorry for the inconvenience, it was a wrong copy/paste "issue"

[yaz]

Originally Posted by LigH

In my opinion, the SAR option works wrong.

it worx right but ... it's not sar but (custom) par.

Originally Posted by LigH

... --sar 16:9 ... ffdshow 2005-07-03 reports an AR of 20/9.

that's correct then (16/9)x(5/4)=(20/9) ~ 2.25:1

the bests
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