How to use VBV?

[Chengbin]

The new mbtree patch changed bitrate distribution, and now I'm forced to use VBV. x264 would give a scene in Coraline 9000Kbps at qcomp 0.6 (704x400 video, CRF 18). I don't want to lower qcomp.

I need to apply a hard cap on the bitrate. If I don't want the bitrate to exceed 5000Kbps ever, how would I do that?

[neuron2]

how would I do that? By using search and reading the existing threads about it.

[vucloutr]

if i understood it right qcomp works the other way around with mbtree so to say.

qcomp=1 is synonymous with mbtree=0.

you could try raising qcomp to 0.7 or 0.8 and and see if that lowers mbtrees influence enough.

[Chengbin]

I know this is a stupid question, but there's got to be a more efficient way of searching. When I search for something, a lot of threads come up, and many of them are really long with tens of pages. There is no way I'm seraching through all that.

Maybe it is the way the search works (or the default), that makes you say use search in countless posts.

[G_M_C]

From the Wiki:

1- vbv-maxrate
Default: 0

Sets the maximum bitrate in VBV mode. You should only use VBV if you have a hardware decoder that requires it. It is highly recommended, though not required, to use 2pass bitrate mode with VBV

So, dont use crf.

Also, to be read numerous times in the --mbtree thread: crf has changed anyway.

so you might have to change you commandline.

[nm]

I know this is a stupid question, but there's got to be a more efficient way of searching. When I search for something, a lot of threads come up, and many of them are really long with tens of pages. There is no way I'm seraching through all that.
Try Google instead of the forum search feature. Example: site:forum.doom9.org x264 vbv (http://www.google.com/search?q=site%3Aforum.doom9.org+x264+vbv).

[LoRd_MuldeR]

Sets the maximum bitrate in VBV mode. You should only use VBV if you have a hardware decoder that requires it.

It should be noted that the maximum VBV bitrate is not the maximum (local) video bitrate, it is the maximum bitrate at which new data can enter the VBV buffer.

In case there's enough data buffered, the video bitrate can have spikes that exceed the maximum VBV bitrate for a short moment.

Still the question: Why do you want to limit the maximum video bitrate? If you were targeting for a "real" hardware player, then the VBV values would be pre-defined by the device.

And otherwise VBV isn't required and hence shouldn't be used, as it potentially hurts quality...

[Chengbin]

I know VBV can hurt quality. That's why I've been avoiding the use of VBV until now.

My Archos 5 cannot play a H.264 video over 5000 (ish)Kbps at 704x400. Anything over that will stutter, no matter how short the peak is. That's why I need a hard cap at 5000Kbps.

[LoRd_MuldeR]

And there are no VBV parameters publicly available for the Archos 5 ??? :confused:

[Chengbin]

And there are no VBV parameters publicly available for the Archos 5 ??? :confused:

No. It is a very niche portable media player.

I found out through testing.

[Rumbah]

Perhaps the Archos support can answer the supportet VBV question, at least it's worth a try I think.

[Chengbin]

Perhaps the Archos support can answer the supportet VBV question, at least it's worth a try I think.

Archos has a notorious reputation for the WORST customer service of any company. Their technicians are CLUELESS.

I wouldn't buy an Archos if I didn't have a choice. It is the only "real" portable media player out there. Apple's video decoding capability is close to zero, it has almost no storage, and the screen is incredibly tiny.