Question / Help NVENC: 288000 Max Bitrate - Bug Or Limitation?

[Schauerland]

Hey,

I've tried to set a high bitrate with NVENC cbr or vbr but 288000 (288 Mbit) ist the maximum i could set.

Recording wont start with error

17:42:03.497: fatal: InitializeEncoder failed: 0x8
17:42:03.510: [NVENC encoder: 'recording_h264'] Failed to open NVENC codec: Generic error in an external library

If i record lossless bitrates are up to 1000000 (1 Gbit) and more is used

My Card is GTX970

thanks

 

[Schyler]

Nothing can write at that speed except for a PCI or M.2 slot SSD. Max bit rate you need is 50 MBps.

 

[Schauerland]

no.
dont confound kbit/s with kb/s

288000 kbit = 288 mbit = 36 MB/s

1000000 bbit = 1000 mbit = 1gbit = 125MB/s and thats totally normal for lossless (x264 qp=0) depending on resolution and image complexity even more

so 288Mbit for nvenc is not much, becaus if you do nvenc lossless it can write gbit/s

 

[Sapiens]

Out of curiosity why would you want to do use such an excessive bitrate instead of something like CQP? If you want lossless, wait for it to be fixed in 0.15.

 

[Schauerland]

im using the 14.2 with fixed lossless but adobe premiere can't handle it right (extrem laggy)

i've good results with x264 @ 800 Mbit (2560x1440 resoulution) and premiere can handle it smooth but only at cbr
if i use vbr or cqp it is very choppy even if the max/avrg bitrate is < 800 Mbit (im using Bitrate Viewer to look into vbr encoding of cqp encoded files)

so just wondering if nvenc is just limiting cbr/vbr while they can do high bitrates.

also, if i use cqp 0 ffmpeg nvenc seems to be limited @ 100 mbit
when media foundation was used before 0.14 i got higer bitrates at cqp 0 and better quality

 

[Schyler]

Use Cqp @10 . Youtube down so your video anyways. And yes, the nvenc codec has a limit because it uses a dedicated chip in your graphics card.

 

[Lain]

When you get "Failed to open NVENC codec: Generic error in an external library", that means the error comes from NVENC itself in that case (the driver). For whatever reason it doesn't like your settings apparently. I couldn't say specifically why.

 

[Schauerland]

Okay, thanks Jim, I feared that.