[FFmpeg-user] -tune zerolatency has no effect with libx264

Moritz Barsnick barsnick at gmx.net
Wed Jan 7 10:15:24 CET 2015

On Wed, Jan 07, 2015 at 00:32:51 +0000, Andy Furniss wrote:
> https://trac.ffmpeg.org/wiki/StreamingGuide
> use -tune zerolatency but it has no effect for me, also tested with -b:v ...

I'm by no means an x264 expert, but the encoder tuning may not be the
only thing to take into consideration:

"What you want to do for low latency encode is to use CBR, and set the
VBV buffer to the size of one frame, exactly. This enables a special
VBV calculation, if you look in the x264 source."

Technical details are here:
and it does sound as if you need to do stuff in addition to the "-tune"
"Because with –tune zerolatency, single-frame VBV, and intra refresh,
x264 can achieve end-to-end latency (not including transport) of under
10 milliseconds for an 800×600 video stream."


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