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Max Bitrates relation to buffer size

Posted: Fri Apr 17, 2009 1:51 pm
by peter893
Max Bitrates relation to buffer size:
Is there are relation? how do they relate? should a given max rate have any specific type of buffer amount?

Is a buffer needed when setting max bitrate anyway? Is buffer only related to streaming over networks?


Edit: opps should have posted this in Devices... please move mods...

Re: Max Bitrates relation to buffer size

Posted: Fri Apr 17, 2009 3:51 pm
by Rodeo

Re: Max Bitrates relation to buffer size

Posted: Sat Apr 18, 2009 3:33 pm
by peter893
Im still not understanding how buffer affects things.

Right now Ive figured that my Mac Mini 1.83ghz running Plex (.13) can handle around a MAX/Peak bitrate of 30mps.
So ive capped it vbv-maxrate=26000 and a bufsize=5000 and Ive set the average bitrate to 20000

Can someone that knows... explain what ive done here? lol and if this is a good idea/setting

Thank you

Re: Max Bitrates relation to buffer size

Posted: Sat Apr 18, 2009 4:26 pm
by Rodeo
Have a look at the logs above. They're a bit technical (I don't fully understand them), but there's a lot of precise info about this featureā€¦

Re: Max Bitrates relation to buffer size

Posted: Sat Apr 18, 2009 8:07 pm
by peter893
Yes, thank for posting the link rodeo. I did read some of it. was looking for someone to expand on my follow up. thanks though...

Re: Max Bitrates relation to buffer size

Posted: Tue Apr 21, 2009 11:14 pm
by dynaflash
peter893 wrote:Im still not understanding how buffer affects things.

Right now Ive figured that my Mac Mini 1.83ghz running Plex (.13) can handle around a MAX/Peak bitrate of 30mps.
So ive capped it vbv-maxrate=26000 and a buffrate=5000 and Ive set the average bitrate to 20000

Can someone that knows... explain what ive done here? lol and if this is a good idea/setting

Thank you
Well, for how long ? a vbv buffer has to have a specified length. this has to be known to determine if you're settings make any sense.

Re: Max Bitrates relation to buffer size

Posted: Wed Apr 22, 2009 1:49 pm
by peter893
dynaflash wrote: Well, for how long ? a vbv buffer has to have a specified length. this has to be known to determine if you're settings make any sense.
How long? you mean the length/time of the movie? can you type in an example?


thanks

Re: Max Bitrates relation to buffer size

Posted: Thu Apr 23, 2009 3:21 am
by dynaflash
well, as the docs you were linked to explain, a video buffer has a size and a length. Not the length of the movie, but the specified length of the devices video buffer. You would get this from the specs or from *alot* of empiricle testing. Video buffer length might be .5 seconds, or one second or ??? basically you do not have enough info about the target video buffer to determine if your settings are sane or not. Its much more complicated than it looks.

Re: Max Bitrates relation to buffer size

Posted: Thu Apr 23, 2009 1:28 pm
by peter893
I Did read the link, but I guess I didnt understand.

So the playback devices/softwares working buffer = the buffsize?

I have had no issue with the moveis Ive done with setting above... what would be some issues if incorrect bufsize was set?