[FFmpeg-devel] [PATCH V2 3/3] avfilter/vf_dnn_processing.c: add frame size change support for planar yuv format

[mypopy at gmail.com]

On Tue, Feb 25, 2020 at 5:24 PM Guo, Yejun <yejun.guo at intel.com> wrote:
>
> The Y channel is handled by dnn, and also resized by dnn. The UV channels
> are resized with swscale.
For me, this is a little weird to resize Y with dnn backend but resize
UV channel with FFmpeg swscale, is it used the same scale algorithm ?

> The command to use espcn.pb (see vf_sr) looks like:
> ./ffmpeg -i 480p.jpg -vf format=yuv420p,dnn_processing=dnn_backend=tensorflow:model=espcn.pb:input=x:output=y -y tmp.espcn.jpg
>
> Signed-off-by: Guo, Yejun <yejun.guo at intel.com>
> ---
>  doc/filters.texi                |  9 +++++++++
>  libavfilter/vf_dnn_processing.c | 37 ++++++++++++++++++++++++++++++-------
>  2 files changed, 39 insertions(+), 7 deletions(-)
>
> diff --git a/doc/filters.texi b/doc/filters.texi
> index 33b7857..e3df8f9 100644
> --- a/doc/filters.texi
> +++ b/doc/filters.texi
> @@ -9155,6 +9155,7 @@ ffmpeg -i INPUT -f lavfi -i nullsrc=hd720,geq='r=128+80*(sin(sqrt((X-W/2)*(X-W/2
>  @end example
>  @end itemize
>
> + at anchor{dnn_processing}
>  @section dnn_processing
>
>  Do image processing with deep neural networks. It works together with another filter
> @@ -9216,6 +9217,12 @@ Handle the Y channel with srcnn.pb (see @ref{sr} filter) for frame with yuv420p
>  ./ffmpeg -i 480p.jpg -vf format=yuv420p,scale=w=iw*2:h=ih*2,dnn_processing=dnn_backend=tensorflow:model=srcnn.pb:input=x:output=y -y srcnn.jpg
>  @end example
>
> + at item
> +Handle the Y channel with espcn.pb (see @ref{sr} filter), which changes frame size, for format yuv420p (planar YUV formats supported):
> + at example
> +./ffmpeg -i 480p.jpg -vf format=yuv420p,dnn_processing=dnn_backend=tensorflow:model=espcn.pb:input=x:output=y -y tmp.espcn.jpg
> + at end example
> +
>  @end itemize
>
>  @section drawbox
> @@ -17369,6 +17376,8 @@ Default value is @code{2}. Scale factor is necessary for SRCNN model, because it
>  input upscaled using bicubic upscaling with proper scale factor.
>  @end table
>
> +This feature can also be finished with @ref{dnn_processing} filter.
> +
>  @section ssim
>
>  Obtain the SSIM (Structural SImilarity Metric) between two input videos.
> diff --git a/libavfilter/vf_dnn_processing.c b/libavfilter/vf_dnn_processing.c
> index f9458f0..7f40f85 100644
> --- a/libavfilter/vf_dnn_processing.c
> +++ b/libavfilter/vf_dnn_processing.c
> @@ -51,6 +51,8 @@ typedef struct DnnProcessingContext {
>
>      struct SwsContext *sws_gray8_to_grayf32;
>      struct SwsContext *sws_grayf32_to_gray8;
> +    struct SwsContext *sws_uv_scale;
> +    int sws_uv_height;
>  } DnnProcessingContext;
>
>  #define OFFSET(x) offsetof(DnnProcessingContext, x)
> @@ -274,6 +276,18 @@ static int prepare_sws_context(AVFilterLink *outlink)
>                                                     outlink->h,
>                                                     AV_PIX_FMT_GRAY8,
>                                                     0, NULL, NULL, NULL);
> +
> +        if (inlink->w != outlink->w || inlink->h != outlink->h) {
> +            const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(fmt);
> +            int sws_src_h = AV_CEIL_RSHIFT(inlink->h, desc->log2_chroma_h);
> +            int sws_src_w = AV_CEIL_RSHIFT(inlink->w, desc->log2_chroma_w);
> +            int sws_dst_h = AV_CEIL_RSHIFT(outlink->h, desc->log2_chroma_h);
> +            int sws_dst_w = AV_CEIL_RSHIFT(outlink->w, desc->log2_chroma_w);
> +            ctx->sws_uv_scale = sws_getContext(sws_src_w, sws_src_h, AV_PIX_FMT_GRAY8,
> +                                               sws_dst_w, sws_dst_h, AV_PIX_FMT_GRAY8,
> +                                               SWS_BICUBIC, NULL, NULL, NULL);
> +            ctx->sws_uv_height = sws_src_h;
> +        }
>          return 0;
>      default:
>          //do nothing
> @@ -404,13 +418,21 @@ static av_always_inline int isPlanarYUV(enum AVPixelFormat pix_fmt)
>
>  static int copy_uv_planes(DnnProcessingContext *ctx, AVFrame *out, const AVFrame *in)
>  {
> -    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(in->format);
> -    int uv_height = AV_CEIL_RSHIFT(in->height, desc->log2_chroma_h);
> -    for (int i = 1; i < 3; ++i) {
> -        int bytewidth = av_image_get_linesize(in->format, in->width, i);
> -        av_image_copy_plane(out->data[i], out->linesize[i],
> -                            in->data[i], in->linesize[i],
> -                            bytewidth, uv_height);
> +    if (!ctx->sws_uv_scale) {
> +        av_assert0(in->height == out->height && in->width == out->width);
> +        const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(in->format);
> +        int uv_height = AV_CEIL_RSHIFT(in->height, desc->log2_chroma_h);
> +        for (int i = 1; i < 3; ++i) {
> +            int bytewidth = av_image_get_linesize(in->format, in->width, i);
> +            av_image_copy_plane(out->data[i], out->linesize[i],
> +                                in->data[i], in->linesize[i],
> +                                bytewidth, uv_height);
> +        }
> +    } else {
> +        sws_scale(ctx->sws_uv_scale, (const uint8_t **)(in->data + 1), in->linesize + 1,
> +                  0, ctx->sws_uv_height, out->data + 1, out->linesize + 1);
> +        sws_scale(ctx->sws_uv_scale, (const uint8_t **)(in->data + 2), in->linesize + 2,
> +                  0, ctx->sws_uv_height, out->data + 2, out->linesize + 2);
>      }
>
>      return 0;
> @@ -455,6 +477,7 @@ static av_cold void uninit(AVFilterContext *ctx)
>
>      sws_freeContext(context->sws_gray8_to_grayf32);
>      sws_freeContext(context->sws_grayf32_to_gray8);
> +    sws_freeContext(context->sws_uv_scale);
>
>      if (context->dnn_module)
>          (context->dnn_module->free_model)(&context->model);
> --
> 2.7.4
>