to use bitrate alone or to also use vbv_maxrate

[phibertron]

If I use the following with mencoder, the file sizes end up the same, which isnt a bad thing, but...
The one with vbv_maxrate specified looks so much better


bitrate=512



bitrate=512
vbv_maxrate=4000
vbv_bufsize=4000


I'm guessing here, but..
Is adding vbv_maxrate allowing for frames to burst to that value?
If so, how are the file sizes the same?
I'm guessing it is allowing peter to rob paul, and the end file size is based off of bitrate?

[nm]

Were they both 2-pass encodes? Could you post sample clips of both cases?

[J_Darnley]

No, if anything, VBV is limiting frame sizes. Is the one with VBV better because it uses two passes? Are you certain that all other settings are the same? The file sizes are the same because you asked the encoder to use 512 kbit/s. And, in your last sentence, what do you mean by "peter to rob paul"?

[phibertron]

Were they both 2-pass encodes? Could you post sample clips of both cases?

i got lazy on, and only did one pass
ill make some samples later today and post them

[phibertron]

No, if anything, VBV is limiting frame sizes. Is the one with VBV better because it uses two passes? Are you certain that all other settings are the same? The file sizes are the same because you asked the encoder to use 512 kbit/s. And, in your last sentence, what do you mean by "peter to rob paul"?

i only did one pass, and the only thing i changed was to add vbv_maxrate and vbv_bufsize

the "peter paul" was my way of trying to say that, and i'm guessing, is that it was taking bits from somewhere else to put them where maxrate wanted them, basically netzero change in size

[Blue_MiSfit]

Don't use VBV unless you have a good reason to :)

Valid reasons:
1) Standalone device compatibility (i.e. for BluRay / AVCHD authoring, game consoles, or other hardware devices)
2) DXVA compatibility

If you're just doing what most folks do - watching encodes on their PC using software decoding - then there's no need to use VBV. Software decoders can handle most anything, provided you have a strong CPU.

Using VBV will never improve quality in and of it itself!

Also, don't ever just do a 1 pass ABR encode unless you really have to ;) 2 pass VBR is always preferred if you're trying to hit a specific file size, or 1 pass CRF if you're just trying to hit an average quality level, and don't care about file size (sort of, it's more complicated than that).

~MiSfit

[phibertron]

Don't use VBV unless you have a good reason to :)

Valid reasons:
1) Standalone device compatibility (i.e. for BluRay / AVCHD authoring, game consoles, or other hardware devices)
2) DXVA compatibility

If you're just doing what most folks do - watching encodes on their PC using software decoding - then there's no need to use VBV. Software decoders can handle most anything, provided you have a strong CPU.

Using VBV will never improve quality in and of it itself!

Also, don't ever just do a 1 pass ABR encode unless you really have to ;) 2 pass VBR is always preferred if you're trying to hit a specific file size, or 1 pass CRF if you're just trying to hit an average quality level, and don't care about file size (sort of, it's more complicated than that).

~MiSfit

Thanks for the feedback
It is an interesting learning curve to all of this
lots of trial, not really error, just finding better ways of doing things

[Blue_MiSfit]

Indeed.

There's always a better way, but never a best way :D

~MiSfit