[FFmpeg-devel] [PATCH, v2 1/2] lavf/qsvvpp: allocate continuous memory

[Li, Zhong]

> From: ffmpeg-devel [mailto:ffmpeg-devel-bounces at ffmpeg.org] On Behalf
> Of Linjie Fu
> Sent: Thursday, May 30, 2019 1:01 AM
> To: ffmpeg-devel at ffmpeg.org
> Cc: Fu, Linjie <linjie.fu at intel.com>
> Subject: [FFmpeg-devel] [PATCH, v2 1/2] lavf/qsvvpp: allocate continuous
> memory
> 
> Mediasdk calls CMRT to copy from video to system memory and requires
> memory to be continuously allocated across Y and UV.
> 
> Add a new path to allocate continuous memory when using system out.
> Use av_image_fill_pointers to arrange data according to pixfmt.
> 
> Signed-off-by: Linjie Fu <linjie.fu at intel.com>
> ---
> [v2]: use av_image_fill_pointers
> 
>  libavfilter/qsvvpp.c | 32 +++++++++++++++++++++++++++-----
>  1 file changed, 27 insertions(+), 5 deletions(-)
> 
> diff --git a/libavfilter/qsvvpp.c b/libavfilter/qsvvpp.c index
> 06efdf5089..6eeed7e632 100644
> --- a/libavfilter/qsvvpp.c
> +++ b/libavfilter/qsvvpp.c
> @@ -27,6 +27,7 @@
>  #include "libavutil/hwcontext_qsv.h"
>  #include "libavutil/time.h"
>  #include "libavutil/pixdesc.h"
> +#include "libavutil/imgutils.h"
> 
>  #include "internal.h"
>  #include "qsvvpp.h"
> @@ -51,6 +52,7 @@ struct QSVVPPContext {
>      enum AVPixelFormat  out_sw_format;   /* Real output format */
>      mfxVideoParam       vpp_param;
>      mfxFrameInfo       *frame_infos;     /* frame info for each
> input */
> +    AVBufferPool       *pool;
> 
>      /* members related to the input/output surface */
>      int                 in_mem_mode;
> @@ -375,10 +377,24 @@ static QSVFrame *query_frame(QSVVPPContext
> *s, AVFilterLink *outlink)
>          out_frame->surface = (mfxFrameSurface1
> *)out_frame->frame->data[3];
>      } else {
>          /* Get a frame with aligned dimensions.
> -         * Libmfx need system memory being 128x64 aligned */
> -        out_frame->frame = ff_get_video_buffer(outlink,
> -
> FFALIGN(outlink->w, 128),
> -
> FFALIGN(outlink->h, 64));
> +         * Libmfx need system memory being 128x64 aligned
> +         * and continuously allocated across Y and UV */
> +        out_frame->frame = av_frame_alloc();
> +        if (!out_frame->frame) {
> +            return NULL;

Should be better to return AVERROR(ENOMEM)? 

> +        }
> +
> +        out_frame->frame->linesize[0] = FFALIGN(outlink->w, 128);
> +        out_frame->frame->linesize[1] = out_frame->frame->linesize[0];
> +        out_frame->frame->buf[0]      = av_buffer_pool_get(s->pool);
> +        out_frame->frame->format      = outlink->format;
> +
> +        if (!out_frame->frame->buf[0])
> +            return NULL;

Same as frame alloc.

> +
> +        av_image_fill_pointers(out_frame->frame->data,
> out_frame->frame->format,
> +                                FFALIGN(outlink->h, 64),
> out_frame->frame->buf[0]->data,
> +
> + out_frame->frame->linesize);
>          if (!out_frame->frame)
>              return NULL;
> 
> @@ -483,8 +499,13 @@ static int init_vpp_session(AVFilterContext *avctx,
> QSVVPPContext *s)
> 
>          av_buffer_unref(&outlink->hw_frames_ctx);
>          outlink->hw_frames_ctx = out_frames_ref;
> -    } else
> +    } else {
>          s->out_mem_mode = MFX_MEMTYPE_SYSTEM_MEMORY;
> +        s->pool =
> av_buffer_pool_init(av_image_get_buffer_size(outlink->format,
> +
> FFALIGN(outlink->w, 128),
> +
> FFALIGN(outlink->h, 64), 1),
> +                                        av_buffer_allocz);

1. What is the benefit to use a pool? Comparing with directly alloc a buffer use av_buffer_allocz()? 
2. av_buffer_allocz() will memset the whole buffer and make performance drop. Is it really necessary here? 
  If no (I believe so), just use av_buffer_alloc()