[FFmpeg-devel] [PATCH v2] avfilter/qsvvpp: Work around a bug in MSDK where VPP processing hangs under certain conditions

[Max Dmitrichenko]

On Sat, Jun 6, 2020 at 7:29 AM Soft Works <softworkz at hotmail.com> wrote:

>
>
> > -----Original Message-----
> > From: ffmpeg-devel <ffmpeg-devel-bounces at ffmpeg.org> On Behalf Of
> > Max Dmitrichenko
> > Sent: Friday, June 5, 2020 3:09 PM
> > To: FFmpeg development discussions and patches <ffmpeg-
> > devel at ffmpeg.org>
> > Subject: Re: [FFmpeg-devel] [PATCH v2] avfilter/qsvvpp: Work around a bug
> > in MSDK where VPP processing hangs under certain conditions
> >
> > On Mon, May 25, 2020 at 12:40 AM Soft Works <softworkz at hotmail.com>
> > wrote:
> >
> > > These are:
> > > - Dimensions are already aligned (e.g. 1920x800)
> > > - No scaling is done
> > > - Color format conversion (e.g. 10bit to 8bit)
> > >
> > > Example command:
> > > ffmpeg -c:v hevc_qsv -hwaccel qsv -i hevc_10bit_1920_800.mkv
> > > -filter_complex "scale_qsv=format=nv12" -c:v h264_qsv out.mkv
> > >
> > > Fix:
> > > - Increase the frame height to the next alignment value
> > >
> > > V2:
> > > - removed empty line
> > > - removed duplicated line
> > > ---
> > >  libavfilter/qsvvpp.c       | 7 ++++++-
> > >  libavfilter/vf_scale_qsv.c | 9 ++++++++-
> > >  2 files changed, 14 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/libavfilter/qsvvpp.c b/libavfilter/qsvvpp.c index
> > > 1bbb7a7e68..98d2353d1c 100644
> > > --- a/libavfilter/qsvvpp.c
> > > +++ b/libavfilter/qsvvpp.c
> > > @@ -420,6 +420,7 @@ static int init_vpp_session(AVFilterContext
> > > *avctx, QSVVPPContext *s)
> > >      mfxHandleType handle_type;
> > >      mfxVersion ver;
> > >      mfxIMPL impl;
> > > +    int height_align_adjust = 0;
> > >      int ret, i;
> > >
> > >      if (inlink->hw_frames_ctx) {
> > > @@ -463,9 +464,13 @@ static int init_vpp_session(AVFilterContext
> > > *avctx, QSVVPPContext *s)
> > >          out_frames_ctx   = (AVHWFramesContext *)out_frames_ref->data;
> > >          out_frames_hwctx = out_frames_ctx->hwctx;
> > >
> > > +        /* work around a bug in MSDK where VPP processing hangs under
> > > certain conditions */
> > > +        if (inlink->h == outlink->h)
> > > +            height_align_adjust = 1;
> > > +
> > >          out_frames_ctx->format            = AV_PIX_FMT_QSV;
> > >          out_frames_ctx->width             = FFALIGN(outlink->w, 32);
> > > -        out_frames_ctx->height            = FFALIGN(outlink->h, 32);
> > > +        out_frames_ctx->height            = FFALIGN(outlink->h +
> > > height_align_adjust, 32);
> > >          out_frames_ctx->sw_format         = s->out_sw_format;
> > >          out_frames_ctx->initial_pool_size = 64;
> > >          if (avctx->extra_hw_frames > 0) diff --git
> > > a/libavfilter/vf_scale_qsv.c b/libavfilter/vf_scale_qsv.c index
> > > 5259104a4f..303d2101a9 100644
> > > --- a/libavfilter/vf_scale_qsv.c
> > > +++ b/libavfilter/vf_scale_qsv.c
> > > @@ -181,8 +181,10 @@ static int init_out_pool(AVFilterContext *ctx,
> > >      AVQSVFramesContext *out_frames_hwctx;
> > >      enum AVPixelFormat in_format;
> > >      enum AVPixelFormat out_format;
> > > +    int height_align_adjust = 0;
> > >      int i, ret;
> > >
> > >      /* check that we have a hw context */
> > >      if (!ctx->inputs[0]->hw_frames_ctx) {
> > >          av_log(ctx, AV_LOG_ERROR, "No hw context provided on
> > > input\n"); @@ -191,6 +193,7 @@ static int init_out_pool(AVFilterContext
> > *ctx,
> > >      in_frames_ctx   =
> > > (AVHWFramesContext*)ctx->inputs[0]->hw_frames_ctx->data;
> > >      in_frames_hwctx = in_frames_ctx->hwctx;
> > >
> > >      in_format     = in_frames_ctx->sw_format;
> > >      out_format    = (s->format == AV_PIX_FMT_NONE) ? in_format :
> > > s->format;
> > >
> > > @@ -200,9 +203,13 @@ static int init_out_pool(AVFilterContext *ctx,
> > >      out_frames_ctx   = (AVHWFramesContext*)outlink->hw_frames_ctx-
> > >data;
> > >      out_frames_hwctx = out_frames_ctx->hwctx;
> > >
> > > +    /* work around a bug in MSDK where VPP processing hangs under
> > > + certain
> > > conditions */
> > > +    if (in_frames_ctx->height == out_height)
> > > +        height_align_adjust = 1;
> > > +
> > >      out_frames_ctx->format            = AV_PIX_FMT_QSV;
> > >      out_frames_ctx->width             = FFALIGN(out_width,  16);
> > > -    out_frames_ctx->height            = FFALIGN(out_height, 16);
> > > +    out_frames_ctx->height            = FFALIGN(out_height +
> > > height_align_adjust, 16);
> > >      out_frames_ctx->sw_format         = out_format;
> > >      out_frames_ctx->initial_pool_size = 4;
> > >
> > > --
> > > 2.26.2.windows.1
> > >
> > >
> > patch seems to be manually edited and cannot be applied automatically.
> >
> > During my tests, I couldn't see any change of behavior with and without
> > patch, more details needed for patch justification.
>
> Well, before talking about the patch - the question is whether you can
> reproduce the hang with the video file I sent you and the command line
> above?
>
> It should be reproducible with drivers corresponding to MSDK 1.31
> I haven't tried with the latest ones (1.32).
>

Exact driver version is more important than MSDK API version,
as there can be the same MSDK API version across different versions of GPU
driver.

No hang is visible with the latest drivers.

regards
Max