How to determin vbvmax/-peak/-size values for Xvid encraw?

[Selur]

Like the topic suggests I'd like to use the vbv settings of xvid encraw like vfw xvid does.

http://www.m4if.org/resources/profiles/index.php A.2 shows the restrictions that come with a profile, but I can't figure out how to translate these tables into vbv settings for xvid.

Would be nice if someone who understands how it works could explain it, with an example.

Thanks :)

Cu Selur

[plugh]

Look at table A.3, the "VBV Buffer Size" and "Maximum Bitrate" columns. The 'peak' parameter is from Divx-land, and is not part of spec (just set it to zero). Note that VBV Size should be multiple of 16384, Max Bitrate a multiple of 400, and 'k' is decimal 1000.

For example Advanced Simple at Level 5,
VBV Buffer Size = 112*16384 = 1,835,008
Max Bitrate = 8000*1000 = 8,000,000
are the values the codec wants.

I assume you just specify those values to encraw, but someone more familiar with it will have to answer that...

[squid_80]

-vbvsize = VBV Buffer Size
-vbvmax = Max Bitrate
Unfortunately I can't remember right now what units encraw expects (bits, bytes, kilobytes...), oops.

Also the vfw interface uses slightly smaller values for VBV buffer size than those in the spec, I'm not sure why. You can see what xvidvfw uses by opening the config, hitting more next to profile@level, going to the levels tab and checking the VBV numbers as each profile is selected.

[plugh]

As noone has ever offered an explanation for vfw's 16368 vs the spec's 16384 difference, I've always assummed it was a typo - though coincidentally(?) it is exactly '16' less, and also 16368/16=1023...

[Selur]

Nice, thx for the infos. :)

[Selur]

Had some time and did a small roundup:

Simple Profiles:

Simple Profile @ Level 0 -vbvsize 163840 -vbvmax 64000
max resolution: 176x144
max 15fps

Simple Profile @ Level 1 -vbvsize 163840 -vbvmax 64000
max resolution: 176x144
Adaptive Quantizer is allowed.

Simple Profile @ Level 2 -vbvsize 655360 -vbvmax 128000
max resolution: 352x288

Simple Profile @ Level 3 -vbvsize 655360 -vbvmax 384000
max resolution: 352x288



Advanced Simple Profiles:
B-Frames, Quarter Pixel Motion Compensation (QPel), Global Motion Compensation (GMC) and MPEG-/Custom Quantizer-Matrizen (CQM) are allowed

Advanced Simple Profile @ Level 0 -vbvsize 163840 -vbvmax 128000
max resolution: 176x144

Advanced Simple Profile @ Level 1 -vbvsize 163840 -vbvmax 128000
max resolution: 176x144

Advanced Simple Profile @ Level 2 -vbvsize 655360 -vbvmax 384000
max resolution: 352x288

Advanced Simple Profile @ Level 3 -vbvsize 655360 -vbvmax 768000
max resolution: 352x288

Advanced Simple Profile @ Level 4 -vbvsize 1310720 -vbvmax 3000000
max resolution: 352x576
Interlacing is allowed

Advanced Simple Profile @ Level 5 -vbvsize 1835008 -vbvmax 8000000
max resolution: 720x576
Interlacing is allowed

Cu Selur

Ps.: also attached Simple Profile L0-L3 Xvid Profiles for MeGui
PPs.: fixed a little bug (AQ is not allowed @L0)

[SeeChestlickRun]

Hello,

Can anyone help me understand this a little more.

I am encoding HD video into XviD at 720p, and I need to set a boundary where the bitrate wouldn't go past a specific number.

How can I do that? Is that related with -vbvmax?

What exactly is -vbvsize anyway?

I also noticed that in MeGUI there is a command for -vbvpeak as well.

Let say, I dont want the bitrate to go past 4500, what should I do?

Thanks for help in advance!

ChestLick

[Sharktooth]

the value should be expressed in bits. So, 4500000, coz it's also divisible by 400.