Need expert advice on MeGUI profile

[kosmonaut]

I'm trying to come up with a usable MeGUI profile for the G1 Android phone from T-Mobile. It's a pretty cool phone, but the documentation for its video playback capabilities has been sorely lacking. So, playing around with the MeGUI iPhone/iPod/Zune profiles and testing many, many files, I've got some initial encoding settings that seem to work.

But I'm still pretty n00bish when it comes to x264 profiles, so any advice you guys have on how to make it more efficient would be very, very helpful.

I should say so far the phone is very tolerant of higher bitrates, but not larger resolutions. Also, CABAC is an absolute no go.

cabac=0 / ref=2 / deblock=1:1:0 / analyse=0x1:0x111 / me=umh / subme=6 / psy_rd=1.0:0.0 / mixed_ref=1 / me_range=12 / chroma_me=1 / trellis=0 / 8x8dct=0 / cqm=0 / deadzone=21,11 / chroma_qp_offset=-2 / threads=3 / nr=0 / decimate=1 / mbaff=0 / bframes=0 / keyint=250 / keyint_min=25 / scenecut=40(pre) / rc=crf / crf=20.0 / qcomp=0.60 / qpmin=10 / qpmax=51 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00

Thanks!

[nurbs]

You should be able to raise --subme (to 8; since you don't use b-frames 7 won't change anything and 9 will be same as 8), which is a good choice if you have psy-rd activated. Apart from that not much you can do. Trellis needs CABAC unfortunately. You could set me-range back to 16, but that probably won't do much.

[kosmonaut]

Thanks nurbs, I will try those suggestions out. Anybody else got some feedback? Is crf=20 overkill for a 480x320 screen?

[Sharktooth]

CRF is a sort of index of quality. CRF will result in higher bitrates at higer res and lower bitrates at lower res.
so, no it's not an overkill. if you're satisfied with CRF 20 quality then CRF 20 is good.

[kosmonaut]

Sharktooth, thanks for the info, it helps.

One other question, is there a procedure to get a profile included in the presets that get offered to MeGUI users? I realize the settings are not all that different from iPod/iPhone settings, but I think it would help other Android users so they don't have to figure it out for themselves.

[Sharktooth]

procedure?
you just make and test it and if it works, post it.
i'll include it in megui.

[kosmonaut]

Great, I'll do that. I'm still testing a few things, but I'm close to being finished with it.

[kosmonaut]

Ok, after quite a bit of testing different encoding options to make sure they worked on the Android G1 phone, and then doing a whole bunch of PSNR and SSIM comparisons, to make sure I wasn't producing compliant but low quality video, I believe the profile is ready.

If anybody wants to take a look and has any feedback (positive or negative) just let me know here or PM me. Just remember the phone is super picky about resolution and won't play anything with a width over 480. Also, I went with CRF since there is no specific size requirement that I could find.

Otherwise, I think it's ready to be included in MeGUI if that's cool with Sharktooth.

[kosmonaut]

Going to respond to my own post ;) but just an update, I've put together a step-by-step guide to encoding with MeGUI for the Android G1. Check it out here (http://www.digitalwerks.org/2009/03/15/video-encoding-for-the-android-step-by-step/).

[b66pak]

thanks...
_

[Sharktooth]

@kosmonaut: i've included a modified version of your preset into megui auto-update.
i've changed it to 2 pass since CRF is not so happy with VBV restrictions. I've also set ME-Range to 16.