[FFmpeg-devel] [PATCH 1/2] libavcodec/qsvenc.c delay in 1 microsecond replaced to more appropriate 500 microseconds

wm4 nfxjfg at googlemail.com
Tue Jul 28 17:39:22 CEST 2015

On Tue, 28 Jul 2015 18:30:56 +0300
Ivan Uskov <ivan.uskov at nablet.com> wrote:

> Hello All,
> The attached patch replaces 1 microsecond delay to 500 microsecond for
> case when MFX library does return MFX_WRN_DEVICE_BUSY status.
> In general this warning never appears for simple encoding or
> transcoding session because GPU so fast so almost always not busy and
> any delay value just not executes.
> But for heavy transcoding tasks for example, when several QSV sessions
> are running simultaneously the using of 1-microsecond delay may be
> result of 1000 iterations per each frame. 
> So here possible a paradoxical case when GPU loading also loads CPU by dummy tasks.
> Official MFX/QSV samples by Intel are use 1 millisecond (i.e. 1000
> microseconds) everywhere where MFX_WRN_DEVICE_BUSY does appear.
> So 500us is much more optimal value than 1us.

Are you 100% sure that there is no event-based way to handle this? Or
does it exist and it's just not used?

More information about the ffmpeg-devel mailing list