[FFmpeg-devel] [FFmpeg-cvslog] lavu/qsv: make a copy as libmfx alignment requirement for uploading

[Li, Zhong]

> From: ffmpeg-devel [mailto:ffmpeg-devel-bounces at ffmpeg.org] On Behalf
> Of Mark Thompson
> Sent: Sunday, October 14, 2018 12:36 AM
> To: ffmpeg-devel at ffmpeg.org
> Subject: Re: [FFmpeg-devel] [FFmpeg-cvslog] lavu/qsv: make a copy as
> libmfx alignment requirement for uploading
> 
> On 11/10/18 06:38, Zhong Li wrote:
> > ffmpeg | branch: master | Zhong Li <zhong.li at intel.com> | Mon Sep 17
> > 19:16:44 2018 +0800| [681aa7d14f97fd98181ca6d61e11be48fe65692d] |
> > committer: Zhong Li
> >
> > lavu/qsv: make a copy as libmfx alignment requirement for uploading
> >
> > Libmfx requires 16 bytes aligned input/output for uploading.
> > Currently only output is 16 byte aligned and assigning same
> > width/height to input with smaller buffer size actually, thus definitely will
> cause segment fault.
> >
> > Can reproduce with any 1080p nv12 rawvideo input:
> > ffmpeg -init_hw_device qsv=qsv:hw -hwaccel qsv -filter_hw_device qsv
> > -f rawvideo -pix_fmt nv12 -s:v 1920x1080 -i 1080p_nv12.yuv -vf
> > 'format=nv12,hwupload=extra_hw_frames=16,hwdownload,format=nv12'
> -an
> > -y out_nv12.yuv
> >
> > It can fix #7418
> >
> > Signed-off-by: Zhong Li <zhong.li at intel.com>
> >
> >>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=681aa7d14f9
> >> 7fd98181ca6d61e11be48fe65692d
> > ---
> >
> >  libavutil/hwcontext_qsv.c | 31 +++++++++++++++++++++++++++++--
> >  1 file changed, 29 insertions(+), 2 deletions(-)
> >
> > diff --git a/libavutil/hwcontext_qsv.c b/libavutil/hwcontext_qsv.c
> > index 33e121b416..814ce215ce 100644
> > --- a/libavutil/hwcontext_qsv.c
> > +++ b/libavutil/hwcontext_qsv.c
> > @@ -862,6 +862,10 @@ static int
> qsv_transfer_data_to(AVHWFramesContext *ctx, AVFrame *dst,
> >      mfxSyncPoint sync = NULL;
> >      mfxStatus err;
> >      int ret = 0;
> > +    /* make a copy if the input is not padded as libmfx requires */
> > +    AVFrame tmp_frame, *src_frame;
> > +    int realigned = 0;
> > +
> >
> >      while (!s->session_upload_init && !s->session_upload && !ret) {
> > #if HAVE_PTHREADS @@ -887,16 +891,36 @@ static int
> > qsv_transfer_data_to(AVHWFramesContext *ctx, AVFrame *dst,
> >      if (ret < 0)
> >          return ret;
> >
> > +
> > +    if (src->height & 16 || src->linesize[0] & 16) {
> 
> Doesn't this still need to check that the layout is compatible with other the
> limitations that libmfx has before trying to do the upload?  In particular,
> that the pitches for the different planes are actually all the same - I certainly
> wouldn't expect them to be for YUV420P.

Do you mean our previous discussion on https://lists.libav.org/pipermail/libav-devel/2018-April/086070.html ?
If yes, I will try to reproduce it with hwupload pipeline instead of transcoding pipeline, and then give an update patch.

> 
> (IIRC there was a requirement 0 < frame->data[N] - frame->data[0] < 2^24
> as well (or something like that, I might be wrong), which also need not be
> true.)

I don't know such a requirement, could it be found from MSDK guide? 

> 
> - Mark