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

[Zhong Li]

Soft Works <softworkz at hotmail.com> 于2020年5月24日周日 下午8:13写道：
>
> These conditions are:
> - Dimensions are aligned to 16/32 byte (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

Could you help to file a bug on https://trac.ffmpeg.org/ or prove a
link to download the tested video hevc_10bit_1920_800.mkv ?

> Fix:
> - Increase the frame height to the next alignment value
> ---
>  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;
>      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;

Probally make sense, but have you tested the width value with similar issue?