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

[Soft Works]

> -----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).

Maybe I haven't specified "hang" well enough. In that case, "hang" means
that ffmpeg totally gets stuck and does nothing, so you need to kill it.

BTW: We have deployed the patch to release last week and the affected
users have reported that it's resolved for them.

softworkz