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mpress03
Jul 31, 2013, 06:35 PM
Hi Everyone,

I have been using handbrake for some time. I created my own Blu-Ray setting some time ago and it seems to have been showing good results so far. I now have the newest version of handbrake (0.9.9). I was comparing my BD setting with the AppleTV 3 preset that is included and have a few questions about the new setting that will probably be easy for those knowledgable about such things.

The AppleTV 3 preset says "vbv-bufsize=31250:vbv-maxrate=25000". What are these settings exactly and are they compressing the BD rips even farther? I am not worried about file size, just quality and everything is hooked up through gigabit ethernet so I am not worried about the size not being able to stream to my AppleTV's (an ATV 2 and an ATV 3). The setting I created is almost identical to the new AppleTV 3 preset except I have b-adapt=2, rc-lookahead=50 and am using anamorphic strict, as well as a few other tweaks that don't matter as much, but these two setting are not included in my personal preset.

Will the AppleTV 3 preset with these extra settings hurt quality for future devices that will stream movies? I would like to future-proof my collection so I don't have to redo the entire collection to get better quality when the next version of streaming devices arrive.

Sorry for the long post and thanks for any help.



dynaflash
Aug 1, 2013, 01:08 PM
The AppleTV 3 preset says "vbv-bufsize=31250:vbv-maxrate=25000". What are these settings exactly and are they compressing the BD rips even farther? I am not worried about file size, just quality and everything is hooked up through gigabit ethernet so I am not worried about the size not being able to stream to my AppleTV's (an ATV 2 and an ATV 3). The setting I created is almost identical to the new AppleTV 3 preset except I have b-adapt=2, rc-lookahead=50 and am using anamorphic strict, as well as a few other tweaks that don't matter as much, but these two setting are not included in my personal preset.

vbv stands for "video buffer verifier" ... while specifically its more than the scope of this thread basically it puts a "cap" on bitrate spikes. Generally its used to make sure streaming is smooth.

Also, adding badapt=2 as you have in your preset to the atv 3 preset is in my opinion a good idea. I pushed for it for the atv3 preset but it didn't go in. Basically if you are using ethernet and have no streaming issues with your custom preset, I would use your custom preset as you have no need for the vbv settings.

mpress03
Aug 1, 2013, 01:31 PM
Thanks. I read that the setting had something to do with buffer sizes but wasn't quite sure what the objective of the setting was. It sounds like these settings will further degrade quality in an attempt to smooth out video during streaming. I am trying to keep the files close to the original but in a format that is easily playable on many devices. Thanks again for your help, I will continue to use my personal preset for now.

dynaflash
Aug 1, 2013, 01:42 PM
It sounds like these settings will further degrade quality in an attempt to smooth out video during streaming.
Well, yes but not always. It puts a cap on. many movies will never require the cap, but lets say you have the opening scene to Harry Potter Order of the Phoenix ... the complexity and graininess of the clouds demand a huge amount of bitrate to maintain quality, so constant quality encoding will ask for a huge amount of bitrate which will choke most streaming situations. the vbv settings cap that so there is a short lowering of bitrate to prevent that. Along with that will be a short degradation in quality for that spike. Typically its very short term, like a second or so. In fact it may not even be seen by the human eye.

So, yes, if you do not have problems with your setup as far as the atv buffering during high bitrates its not a concern to you.

mpress03
Aug 1, 2013, 01:51 PM
That makes sense. This is not such a bad feature if it only works for a second or so. I plan to leave it off, but it is definitely something to consider if my setup changes and wifi streaming is added to the mix.

On a somewhat related note, I am using anamorphic strict. I have noticed that none of the built in presets use strict. Should I also change my preset too anamorphic - loose and modulus - 2?