Interlaced encoding, VBV buffer size/maxrate for PCH

[Boulder]

Hello,

being a new owner of a Popcorn Hour A-110 and a newbie regarding MPEG-4 AVC issues, I have some questions regarding interlaced encoding and VBV buffer size and maxrate. I wasn't able to find solid answers so I opened a new thread :)

1) Interlaced encoding; what options are a no-no and does x264 automatically disable them if encoding as interlaced?

2) Is it actually better (quality-wise and/or size-wise) to bob the stream to 50 fps and encode as progressive?

3) VBV-buffer size and maxrate; if I'm encoding SD material, should I use level 3.1 and its settings for VBV buffer or can I go to level 4.1? As far as I know, the Popcorn Hour supports max level 4.1. I found this (old) thread from the AVS forum but I'm not sure whether the advice still applies: http://www.avsforum.com/avs-vb/showthread.php?t=972503

[Dark Shikari]

1) Interlaced encoding; what options are a no-no and does x264 automatically disable them if encoding as interlaced?x264 will warn you and disable them.2) Is it actually better (quality-wise and/or size-wise) to bob the stream to 50 fps and encode as progressive?No, bobbing will be worse unless you use a slow and smart bobber (and thus get better deinterlacing quality than the device would have). Even then, it'll take more bitrate.3) VBV-buffer size and maxrate; if I'm encoding SD material, should I use level 3.1 and its settings for VBV buffer or can I go to level 4.1? As far as I know, the Popcorn Hour supports max level 4.1. I found this (old) thread from the AVS forum but I'm not sure whether the advice still applies: http://www.avsforum.com/avs-vb/showthread.php?t=972503I assume it can do 4.1 for both.

[Boulder]

Thanks DS :)

Is interlaced encoding currently just left as it is or will there be any developments in the near future? I realize that it is old tech so there might not be any interest in making interlaced encoding more effective.

[Boulder]

And additionally, what is the real vbv-bufsize and vbv-maxrate to use for level 4.1 compliance? I've seen basically anything from 25000 to 50000 being used, but the table at Wikipedia says 62500 at High Profile for maximum video bitrate.

[shon3i]

For L 4.1 High profile:

AVC specs: vbv-bufsize 62500 vbv-maxrate 62500
BD specs: vbv-bufsize 30000 vbv-maxrate 40000

[Boulder]

Thanks :) Guess I'll stick to the BD specs to keep safe, for the SD encodes it probably won't make a difference anyway.

[shon3i]

for the SD encodes it probably won't make a difference anyway. http://tom.niko.users.sbb.rs/bdtable.jpg

[Boulder]

Thanks, that's a useful table :)

[laserfan]

FWIW Boulder I have an A-100, and had no trouble playing a BD on my PC and streaming it over the network! I was surprised this worked, though my A-100 doesn't handle all audio types so I can't do this for every BD disc, but it attests to the ability of the PCH chipset to handle the BD spec programs.

[Dark Shikari]

Do note that the PCH, as do most standalones that aren't Blu-ray players, as do many actual Blu-ray players, don't give a crap about the Blu-ray specs.

[laserfan]

...and, that's A Good Thing!

[Boulder]

Do note that the PCH, as do most standalones that aren't Blu-ray players, as do many actual Blu-ray players, don't give a crap about the Blu-ray specs.

Yep, that's the great thing about them :)

I am considering using the VBV settings 30000 and 40000, and maximum reference frames (since I run my encodes during the night and/or when I'm at work) that is supported by the player. For SD, I think it does support 16. If I ever run across any HD material, I need to do the math.

[Blue_MiSfit]

Indeed.

Still, if you're targeting a wide audience, then it's definitely advisable to stick to a certain spec as strictly as you can.

~MiSfit

[Boulder]

Still, if you're targeting a wide audience, then it's definitely advisable to stick to a certain spec as strictly as you can.

~MiSfitMy goal is just to archive recorded DVB transport streams, the TV series with multiple DVDs per season and the kids' DVDs which I always have to try to find somewhere. The PCH is perfect for these needs, but I just want to make sure there won't be any VBV buffer issues :)

[SomeJoe]

I've been encoding SD material for the PCH for a while now, and have been using level 4.1, 4 reference frames (I know it can go higher for SD, but I've never bothered), and VBV Buffer/VBV Maxrate of 30000/40000.

I don't typically use the CRF mode of x264, I like to be able to predict the file size. I typically use bitrates of 2.1 Mbps for 24 fps material, and 2.6 Mbps for 30 fps interlaced material.

I also typically use some fairly slow x264 options, like preset slow, subme 7, b-pyramid, and no-fast-pskip.

I use these settings to mux H.264, AC3, SRT, and chapter points into an MKV for playback. This seems to work properly, although the PCH will sometimes run into transport issues if you do a lot of pause/play and rew/ff. If that happens, just back up 30 seconds using the left arrow on the PCH remote.

[nm]

I also typically use some fairly slow x264 options, like preset slow, subme 7, b-pyramid, and no-fast-pskip.
Preset "slow" uses subme 8 (http://mewiki.project357.com/wiki/X264_Settings#preset), so there's no point overriding that, especially when you use no-fast-pskip that is only enabled by "placebo" preset. It's better to spend that time elsewhere by using preset "slower" or "veryslow".

[SomeJoe]

Preset "slow" uses subme 8 (http://mewiki.project357.com/wiki/X264_Settings#preset), so there's no point overriding that, especially when you use no-fast-pskip that is only enabled by "placebo" preset. It's better to spend that time elsewhere by using preset "slower" or "veryslow".

Very cool, thanks.

I don't pretend to know a huge amount about how x264's options interact -- my original command lines were from an earlier version of MeGUI when the x264 build it used didn't have presets, and I've then updated those command lines for newer builds of x264.

I was just trying to let the OP know of some x264 options that worked properly for me for the PCH.

With this info, I will probably take out the no-fast-pskip and not override the subme parameter, but instead just stay with preset slow.