[FFmpeg-devel] [PATCH] libavcodec/qsvenc_hevc: correction for QSV HEVC default plugin selection on Windows

[Maxym Dmytrychenko]

On Sat, Oct 13, 2018 at 6:43 PM Mark Thompson <sw at jkqxz.net> wrote:

> On 06/10/18 07:21, Landgraph wrote:
> > 1. Old logic meaned: everywhere, except Windows, ffmpeg has to use HW
> acceleration, but on Windows ffmpeg has to use (unavailable) software
> encode by default
> > 2. Software encode is available only if you provide corresponding
> software MediaSDK library, which isn't provided with ffmpeg. More
> information could be found in
> https://github.com/Intel-Media-SDK/MediaSDK/blob/master/doc/samples/readme-encode_linux.pdf
> > 3. HW encode is available on Windows in the driver by default
>
> This has been proposed before - I can't find the original discussion
> (maybe it was on IRC), but I did find <
> https://lists.libav.org/pipermail/libav-devel/2016-November/080419.html>.
> The reason for not doing it is that a subset of the Intel drivers segfault
> immediately when the hardware plugin is loaded on some platforms.  That's a
> pain for anyone wanting to support diverse systems, so the decision was to
> continue to load the sw plugin by default so it doesn't crash (even if the
> software plugin isn't present), and leave the non-default case as the
> crashing one so the user has to do something to trigger it.
>
> If you can characterise either the set of platforms it crashes on or a set
> of platforms it definitely works on then maybe we could conditionally
> change the default behaviour?
>
> - Mark
>
>
it was 2 years old discussion and with early drivers (we even had this
development a bit ahead of general driver availability)
now it should be working on most of the platforms - I would suggest to make
a positive side.



>
> > ---
> >  libavcodec/qsvenc_hevc.c | 4 ----
> >  1 file changed, 4 deletions(-)
> >
> > diff --git a/libavcodec/qsvenc_hevc.c b/libavcodec/qsvenc_hevc.c
> > index 4339b316a3..e7ca27d49f 100644
> > --- a/libavcodec/qsvenc_hevc.c
> > +++ b/libavcodec/qsvenc_hevc.c
> > @@ -217,11 +217,7 @@ static av_cold int qsv_enc_close(AVCodecContext
> *avctx)
> >      return ff_qsv_enc_close(avctx, &q->qsv);
> >  }
> >
> > -#if defined(_WIN32)
> > -#define LOAD_PLUGIN_DEFAULT LOAD_PLUGIN_HEVC_SW
> > -#else
> >  #define LOAD_PLUGIN_DEFAULT LOAD_PLUGIN_HEVC_HW
> > -#endif
> >
> >  #define OFFSET(x) offsetof(QSVHEVCEncContext, x)
> >  #define VE AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_ENCODING_PARAM
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