[FFmpeg-user] A question on -tag:v and CPU usage

Dennis Mungai dmngaie at gmail.com
Wed Oct 30 04:44:45 EET 2019

On Wed, 30 Oct 2019 at 05:40, Ted Park <kumowoon1025 at gmail.com> wrote:

> > Does it write the video codec tag per frame, etc?
> Not even, It’s per sample, iirc, but
> > I ask because I'm seeing some truly abnormal results with hevc_nvenc when
> > the -tag:v hvc1 option is passed where the CPU load spikes up
> significantly.
> hvc1 is the one with codec params in the sample description box, so I
> guess it’s parsing (basically decoding, as I’ve been told) the stream to
> copy it to the header. (Or box, I should say, rather. And I’m not sure if
> it also deletes them after, but I’m pretty sure there’s a separate bsf that
> does that though.)

Hmm thanks, that second part may explain the spike in CPU load.


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