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[HELP] Bitrates (NVEncC) - Printable Version

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Bitrates (NVEncC) - weyb06 - 15.09.2018

Hi,

I encoded with NVEnc, codec = h265 with "variable bitrate(HQ)" as suggested  Rolleyes, with :
- bitrate : 1500 (default)
- Max Bitrate : 240000 (default)
in "NVEnc / Base".

but when I look to the encoded files, one is 1569kbps & the 2nd is 1870 kbps (video bitrate as seen with MediaInfo)

Q1 : why do they have a video bitrate > 1500 ?
Q2 : what do these 2 parameters mean / how should I use them / are the default figures well chosen ?

regards

RE: Bitrates - Selur - 15.09.2018

You need to know whether you want to stick with the default values

Quote:why do they have a video bitrate > 1500 ?
Did you read the tool-tip?
Quote:variable bitrate (1pass) is a one pass encoding mode for people who just want to get an average bitrate as fast as possible, the bitrate can fluctuate a lot an the average bitrate provided is only a roughly indicator for the encoder.
it clearly states the average bitrate provided is only a roughly indicator for the encoder.

Quote: what do these 2 parameters mean
bitrate: sets a rough indicator to the encoder what average bitrate it should aim for
max bitrate: indicates a bitrate limit to the encoder, "do never use more than X kBit/s"

Quote: how should I use them
You set:
bitrate to the value you want your output to have in average
max bitrate to a value that doesn't cause any trouble during playback
If you can't figure out how to set bitrates according to what you need for your content, try using a fixed quantizer instead.

Quote: are the default figures well chosen ?
if you have to ask, then: 'No, the default values are not chosen well for your usage scenario / input / output / ..."
And no, I got no clue what values would be well chosen values.

-> If you can't figure out to get a decent quality out of NVEncC, then you shouldn't use it. Smile

Cu Selur

RE: Bitrates (NVEncC) - weyb06 - 16.09.2018

Hi,

1. I had read the tool-tip about "bitrate (kbits/s) is "select if you aim a specific bit rate", an not the one about "encoding mode"...

2. I'll have a look at the constant quantizer configuration asap

regards