lavfi: add a QSV scaling filter

This merges libav commit ac7bfd69678f3966e38debdb27f4bde94dc0345c,
which was previously skipped.

(cherry picked from commit ac7bfd69678f3966e38debdb27f4bde94dc0345c)
Signed-off-by: Mark Thompson <sw@jkqxz.net>

7 files changed, 640 insertions, 2 deletions

diff --git a/Changelog b/Changelog
index 13628ca28b..ac9998ec4f 100644
--- a/Changelog
+++ b/Changelog
@@ -26,6 +26,7 @@ version <next>:
 - native Opus encoder
 - ScreenPressor decoder
 - incomplete ClearVideo decoder
+- Intel QSV video scaling filter
 
 version 3.2:
 - libopenmpt demuxer
diff --git a/configure b/configure
index 707b98011a..dc18bfa43e 100755
--- a/configure
+++ b/configure
@@ -3127,6 +3127,7 @@ rubberband_filter_deps="librubberband"
 sab_filter_deps="gpl swscale"
 scale2ref_filter_deps="swscale"
 scale_filter_deps="swscale"
+scale_qsv_filter_deps="libmfx"
 select_filter_select="pixelutils"
 showcqt_filter_deps="avcodec avformat swscale"
 showcqt_filter_select="fft"
diff --git a/doc/libav-merge.txt b/doc/libav-merge.txt
index 39d846f8fc..50eb34fd7c 100644
--- a/doc/libav-merge.txt
+++ b/doc/libav-merge.txt
@@ -94,7 +94,6 @@ Stuff that didn't reach the codebase:
   - a853388d2 hevc: change the stride of the MC buffer to be in bytes instead of elements
   - 0cef06df0 checkasm: add HEVC MC tests
   - e7078e842 hevcdsp: add x86 SIMD for MC
-- QSV scaling filter (62c58c5)
 
 Collateral damage that needs work locally:
 ------------------------------------------
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index 0ba1c74a26..4d1180babb 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -261,6 +261,7 @@ OBJS-$(CONFIG_ROTATE_FILTER)                 += vf_rotate.o
 OBJS-$(CONFIG_SAB_FILTER)                    += vf_sab.o
 OBJS-$(CONFIG_SCALE_FILTER)                  += vf_scale.o scale.o
 OBJS-$(CONFIG_SCALE_NPP_FILTER)              += vf_scale_npp.o scale.o
+OBJS-$(CONFIG_SCALE_QSV_FILTER)              += vf_scale_qsv.o
 OBJS-$(CONFIG_SCALE_VAAPI_FILTER)            += vf_scale_vaapi.o scale.o
 OBJS-$(CONFIG_SCALE2REF_FILTER)              += vf_scale.o scale.o
 OBJS-$(CONFIG_SELECT_FILTER)                 += f_select.o
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index df1af8de23..6aa482d910 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -271,6 +271,7 @@ static void register_all(void)
     REGISTER_FILTER(SAB,            sab,            vf);
     REGISTER_FILTER(SCALE,          scale,          vf);
     REGISTER_FILTER(SCALE_NPP,      scale_npp,      vf);
+    REGISTER_FILTER(SCALE_QSV,      scale_qsv,      vf);
     REGISTER_FILTER(SCALE_VAAPI,    scale_vaapi,    vf);
     REGISTER_FILTER(SCALE2REF,      scale2ref,      vf);
     REGISTER_FILTER(SELECT,         select,         vf);
diff --git a/libavfilter/version.h b/libavfilter/version.h
index 11db8d5513..878711d907 100644
--- a/libavfilter/version.h
+++ b/libavfilter/version.h
@@ -30,7 +30,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVFILTER_VERSION_MAJOR   6
-#define LIBAVFILTER_VERSION_MINOR  74
+#define LIBAVFILTER_VERSION_MINOR  75
 #define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
diff --git a/libavfilter/vf_scale_qsv.c b/libavfilter/vf_scale_qsv.c
new file mode 100644
index 0000000000..88fca8b461
--- /dev/null
+++ b/libavfilter/vf_scale_qsv.c
@@ -0,0 +1,635 @@
+/*
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * scale video filter - QSV
+ */
+
+#include <mfx/mfxvideo.h>
+
+#include <stdio.h>
+#include <string.h>
+
+#include "libavutil/avstring.h"
+#include "libavutil/common.h"
+#include "libavutil/eval.h"
+#include "libavutil/hwcontext.h"
+#include "libavutil/hwcontext_qsv.h"
+#include "libavutil/internal.h"
+#include "libavutil/mathematics.h"
+#include "libavutil/opt.h"
+#include "libavutil/pixdesc.h"
+#include "libavutil/time.h"
+
+#include "avfilter.h"
+#include "formats.h"
+#include "internal.h"
+#include "video.h"
+
+static const char *const var_names[] = {
+    "PI",
+    "PHI",
+    "E",
+    "in_w",   "iw",
+    "in_h",   "ih",
+    "out_w",  "ow",
+    "out_h",  "oh",
+    "a", "dar",
+    "sar",
+    NULL
+};
+
+enum var_name {
+    VAR_PI,
+    VAR_PHI,
+    VAR_E,
+    VAR_IN_W,   VAR_IW,
+    VAR_IN_H,   VAR_IH,
+    VAR_OUT_W,  VAR_OW,
+    VAR_OUT_H,  VAR_OH,
+    VAR_A, VAR_DAR,
+    VAR_SAR,
+    VARS_NB
+};
+
+typedef struct QSVScaleContext {
+    const AVClass *class;
+
+    AVBufferRef *out_frames_ref;
+    /* a clone of the main session, used internally for scaling */
+    mfxSession   session;
+
+    mfxMemId *mem_ids_in;
+    int nb_mem_ids_in;
+
+    mfxMemId *mem_ids_out;
+    int nb_mem_ids_out;
+
+    mfxFrameSurface1 **surface_ptrs_in;
+    int             nb_surface_ptrs_in;
+
+    mfxFrameSurface1 **surface_ptrs_out;
+    int             nb_surface_ptrs_out;
+
+    mfxExtOpaqueSurfaceAlloc opaque_alloc;
+    mfxExtBuffer            *ext_buffers[1];
+
+    int shift_width, shift_height;
+
+    /**
+     * New dimensions. Special values are:
+     *   0 = original width/height
+     *  -1 = keep original aspect
+     */
+    int w, h;
+
+    /**
+     * Output sw format. AV_PIX_FMT_NONE for no conversion.
+     */
+    enum AVPixelFormat format;
+
+    char *w_expr;               ///< width  expression string
+    char *h_expr;               ///< height expression string
+    char *format_str;
+} QSVScaleContext;
+
+static int qsvscale_init(AVFilterContext *ctx)
+{
+    QSVScaleContext *s = ctx->priv;
+
+    if (!strcmp(s->format_str, "same")) {
+        s->format = AV_PIX_FMT_NONE;
+    } else {
+        s->format = av_get_pix_fmt(s->format_str);
+        if (s->format == AV_PIX_FMT_NONE) {
+            av_log(ctx, AV_LOG_ERROR, "Unrecognized pixel format: %s\n", s->format_str);
+            return AVERROR(EINVAL);
+        }
+    }
+
+    return 0;
+}
+
+static void qsvscale_uninit(AVFilterContext *ctx)
+{
+    QSVScaleContext *s = ctx->priv;
+
+    if (s->session) {
+        MFXClose(s->session);
+        s->session = NULL;
+    }
+    av_buffer_unref(&s->out_frames_ref);
+
+    av_freep(&s->mem_ids_in);
+    av_freep(&s->mem_ids_out);
+    s->nb_mem_ids_in  = 0;
+    s->nb_mem_ids_out = 0;
+
+    av_freep(&s->surface_ptrs_in);
+    av_freep(&s->surface_ptrs_out);
+    s->nb_surface_ptrs_in  = 0;
+    s->nb_surface_ptrs_out = 0;
+}
+
+static int qsvscale_query_formats(AVFilterContext *ctx)
+{
+    static const enum AVPixelFormat pixel_formats[] = {
+        AV_PIX_FMT_QSV, AV_PIX_FMT_NONE,
+    };
+    AVFilterFormats *pix_fmts  = ff_make_format_list(pixel_formats);
+    int ret;
+
+    if ((ret = ff_set_common_formats(ctx, pix_fmts)) < 0)
+        return ret;
+
+    return 0;
+}
+
+static int init_out_pool(AVFilterContext *ctx,
+                         int out_width, int out_height)
+{
+    QSVScaleContext *s = ctx->priv;
+
+    AVHWFramesContext *in_frames_ctx;
+    AVHWFramesContext *out_frames_ctx;
+    AVQSVFramesContext *in_frames_hwctx;
+    AVQSVFramesContext *out_frames_hwctx;
+    enum AVPixelFormat in_format;
+    enum AVPixelFormat out_format;
+    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");
+        return AVERROR(EINVAL);
+    }
+    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;
+
+    s->out_frames_ref = av_hwframe_ctx_alloc(in_frames_ctx->device_ref);
+    if (!s->out_frames_ref)
+        return AVERROR(ENOMEM);
+    out_frames_ctx   = (AVHWFramesContext*)s->out_frames_ref->data;
+    out_frames_hwctx = out_frames_ctx->hwctx;
+
+    out_frames_ctx->format            = AV_PIX_FMT_QSV;
+    out_frames_ctx->width             = FFALIGN(out_width,  32);
+    out_frames_ctx->height            = FFALIGN(out_height, 32);
+    out_frames_ctx->sw_format         = out_format;
+    out_frames_ctx->initial_pool_size = 32;
+
+    out_frames_hwctx->frame_type = in_frames_hwctx->frame_type;
+
+    ret = av_hwframe_ctx_init(s->out_frames_ref);
+    if (ret < 0)
+        return ret;
+
+    for (i = 0; i < out_frames_hwctx->nb_surfaces; i++) {
+        mfxFrameInfo *info = &out_frames_hwctx->surfaces[i].Info;
+        info->CropW = out_width;
+        info->CropH = out_height;
+    }
+
+    return 0;
+}
+
+static mfxStatus frame_alloc(mfxHDL pthis, mfxFrameAllocRequest *req,
+                             mfxFrameAllocResponse *resp)
+{
+    AVFilterContext *ctx = pthis;
+    QSVScaleContext   *s = ctx->priv;
+
+    if (!(req->Type & MFX_MEMTYPE_VIDEO_MEMORY_PROCESSOR_TARGET) ||
+        !(req->Type & (MFX_MEMTYPE_FROM_VPPIN | MFX_MEMTYPE_FROM_VPPOUT)) ||
+        !(req->Type & MFX_MEMTYPE_EXTERNAL_FRAME))
+        return MFX_ERR_UNSUPPORTED;
+
+    if (req->Type & MFX_MEMTYPE_FROM_VPPIN) {
+        resp->mids           = s->mem_ids_in;
+        resp->NumFrameActual = s->nb_mem_ids_in;
+    } else {
+        resp->mids           = s->mem_ids_out;
+        resp->NumFrameActual = s->nb_mem_ids_out;
+    }
+
+    return MFX_ERR_NONE;
+}
+
+static mfxStatus frame_free(mfxHDL pthis, mfxFrameAllocResponse *resp)
+{
+    return MFX_ERR_NONE;
+}
+
+static mfxStatus frame_lock(mfxHDL pthis, mfxMemId mid, mfxFrameData *ptr)
+{
+    return MFX_ERR_UNSUPPORTED;
+}
+
+static mfxStatus frame_unlock(mfxHDL pthis, mfxMemId mid, mfxFrameData *ptr)
+{
+    return MFX_ERR_UNSUPPORTED;
+}
+
+static mfxStatus frame_get_hdl(mfxHDL pthis, mfxMemId mid, mfxHDL *hdl)
+{
+    *hdl = mid;
+    return MFX_ERR_NONE;
+}
+
+static const mfxHandleType handle_types[] = {
+    MFX_HANDLE_VA_DISPLAY,
+    MFX_HANDLE_D3D9_DEVICE_MANAGER,
+    MFX_HANDLE_D3D11_DEVICE,
+};
+
+static int init_out_session(AVFilterContext *ctx)
+{
+
+    QSVScaleContext                   *s = ctx->priv;
+    AVHWFramesContext     *in_frames_ctx = (AVHWFramesContext*)ctx->inputs[0]->hw_frames_ctx->data;
+    AVHWFramesContext    *out_frames_ctx = (AVHWFramesContext*)s->out_frames_ref->data;
+    AVQSVFramesContext  *in_frames_hwctx = in_frames_ctx->hwctx;
+    AVQSVFramesContext *out_frames_hwctx = out_frames_ctx->hwctx;
+    AVQSVDeviceContext     *device_hwctx = in_frames_ctx->device_ctx->hwctx;
+
+    int opaque = !!(in_frames_hwctx->frame_type & MFX_MEMTYPE_OPAQUE_FRAME);
+
+    mfxHDL handle = NULL;
+    mfxHandleType handle_type;
+    mfxVersion ver;
+    mfxIMPL impl;
+    mfxVideoParam par;
+    mfxStatus err;
+    int i;
+
+    /* extract the properties of the "master" session given to us */
+    err = MFXQueryIMPL(device_hwctx->session, &impl);
+    if (err == MFX_ERR_NONE)
+        err = MFXQueryVersion(device_hwctx->session, &ver);
+    if (err != MFX_ERR_NONE) {
+        av_log(ctx, AV_LOG_ERROR, "Error querying the session attributes\n");
+        return AVERROR_UNKNOWN;
+    }
+
+    for (i = 0; i < FF_ARRAY_ELEMS(handle_types); i++) {
+        err = MFXVideoCORE_GetHandle(device_hwctx->session, handle_types[i], &handle);
+        if (err == MFX_ERR_NONE) {
+            handle_type = handle_types[i];
+            break;
+        }
+    }
+
+    /* create a "slave" session with those same properties, to be used for
+     * actual scaling */
+    err = MFXInit(impl, &ver, &s->session);
+    if (err != MFX_ERR_NONE) {
+        av_log(ctx, AV_LOG_ERROR, "Error initializing a session for scaling\n");
+        return AVERROR_UNKNOWN;
+    }
+
+    if (handle) {
+        err = MFXVideoCORE_SetHandle(s->session, handle_type, handle);
+        if (err != MFX_ERR_NONE)
+            return AVERROR_UNKNOWN;
+    }
+
+    memset(&par, 0, sizeof(par));
+
+    if (opaque) {
+        s->surface_ptrs_in = av_mallocz_array(in_frames_hwctx->nb_surfaces,
+                                              sizeof(*s->surface_ptrs_in));
+        if (!s->surface_ptrs_in)
+            return AVERROR(ENOMEM);
+        for (i = 0; i < in_frames_hwctx->nb_surfaces; i++)
+            s->surface_ptrs_in[i] = in_frames_hwctx->surfaces + i;
+        s->nb_surface_ptrs_in = in_frames_hwctx->nb_surfaces;
+
+        s->surface_ptrs_out = av_mallocz_array(out_frames_hwctx->nb_surfaces,
+                                               sizeof(*s->surface_ptrs_out));
+        if (!s->surface_ptrs_out)
+            return AVERROR(ENOMEM);
+        for (i = 0; i < out_frames_hwctx->nb_surfaces; i++)
+            s->surface_ptrs_out[i] = out_frames_hwctx->surfaces + i;
+        s->nb_surface_ptrs_out = out_frames_hwctx->nb_surfaces;
+
+        s->opaque_alloc.In.Surfaces   = s->surface_ptrs_in;
+        s->opaque_alloc.In.NumSurface = s->nb_surface_ptrs_in;
+        s->opaque_alloc.In.Type       = in_frames_hwctx->frame_type;
+
+        s->opaque_alloc.Out.Surfaces   = s->surface_ptrs_out;
+        s->opaque_alloc.Out.NumSurface = s->nb_surface_ptrs_out;
+        s->opaque_alloc.Out.Type       = out_frames_hwctx->frame_type;
+
+        s->opaque_alloc.Header.BufferId = MFX_EXTBUFF_OPAQUE_SURFACE_ALLOCATION;
+        s->opaque_alloc.Header.BufferSz = sizeof(s->opaque_alloc);
+
+        s->ext_buffers[0] = (mfxExtBuffer*)&s->opaque_alloc;
+
+        par.ExtParam    = s->ext_buffers;
+        par.NumExtParam = FF_ARRAY_ELEMS(s->ext_buffers);
+
+        par.IOPattern = MFX_IOPATTERN_IN_OPAQUE_MEMORY | MFX_IOPATTERN_OUT_OPAQUE_MEMORY;
+    } else {
+        mfxFrameAllocator frame_allocator = {
+            .pthis  = ctx,
+            .Alloc  = frame_alloc,
+            .Lock   = frame_lock,
+            .Unlock = frame_unlock,
+            .GetHDL = frame_get_hdl,
+            .Free   = frame_free,
+        };
+
+        s->mem_ids_in = av_mallocz_array(in_frames_hwctx->nb_surfaces,
+                                         sizeof(*s->mem_ids_in));
+        if (!s->mem_ids_in)
+            return AVERROR(ENOMEM);
+        for (i = 0; i < in_frames_hwctx->nb_surfaces; i++)
+            s->mem_ids_in[i] = in_frames_hwctx->surfaces[i].Data.MemId;
+        s->nb_mem_ids_in = in_frames_hwctx->nb_surfaces;
+
+        s->mem_ids_out = av_mallocz_array(out_frames_hwctx->nb_surfaces,
+                                          sizeof(*s->mem_ids_out));
+        if (!s->mem_ids_out)
+            return AVERROR(ENOMEM);
+        for (i = 0; i < out_frames_hwctx->nb_surfaces; i++)
+            s->mem_ids_out[i] = out_frames_hwctx->surfaces[i].Data.MemId;
+        s->nb_mem_ids_out = out_frames_hwctx->nb_surfaces;
+
+        err = MFXVideoCORE_SetFrameAllocator(s->session, &frame_allocator);
+        if (err != MFX_ERR_NONE)
+            return AVERROR_UNKNOWN;
+
+        par.IOPattern = MFX_IOPATTERN_IN_VIDEO_MEMORY | MFX_IOPATTERN_OUT_VIDEO_MEMORY;
+    }
+
+    par.AsyncDepth = 1;    // TODO async
+
+    par.vpp.In  = in_frames_hwctx->surfaces[0].Info;
+    par.vpp.Out = out_frames_hwctx->surfaces[0].Info;
+
+    /* Apparently VPP requires the frame rate to be set to some value, otherwise
+     * init will fail (probably for the framerate conversion filter). Since we
+     * are only doing scaling here, we just invent an arbitrary
+     * value */
+    par.vpp.In.FrameRateExtN  = 25;
+    par.vpp.In.FrameRateExtD  = 1;
+    par.vpp.Out.FrameRateExtN = 25;
+    par.vpp.Out.FrameRateExtD = 1;
+
+    err = MFXVideoVPP_Init(s->session, &par);
+    if (err != MFX_ERR_NONE) {
+        av_log(ctx, AV_LOG_ERROR, "Error opening the VPP for scaling\n");
+        return AVERROR_UNKNOWN;
+    }
+
+    return 0;
+}
+
+static int init_scale_session(AVFilterContext *ctx, int in_width, int in_height,
+                              int out_width, int out_height)
+{
+    QSVScaleContext *s = ctx->priv;
+
+    int ret;
+
+    qsvscale_uninit(ctx);
+
+    ret = init_out_pool(ctx, out_width, out_height);
+    if (ret < 0)
+        return ret;
+
+    ret = init_out_session(ctx);
+    if (ret < 0)
+        return ret;
+
+    av_buffer_unref(&ctx->outputs[0]->hw_frames_ctx);
+    ctx->outputs[0]->hw_frames_ctx = av_buffer_ref(s->out_frames_ref);
+    if (!ctx->outputs[0]->hw_frames_ctx)
+        return AVERROR(ENOMEM);
+
+    return 0;
+}
+
+static int qsvscale_config_props(AVFilterLink *outlink)
+{
+    AVFilterContext *ctx = outlink->src;
+    AVFilterLink *inlink = outlink->src->inputs[0];
+    QSVScaleContext  *s = ctx->priv;
+    int64_t w, h;
+    double var_values[VARS_NB], res;
+    char *expr;
+    int ret;
+
+    var_values[VAR_PI]    = M_PI;
+    var_values[VAR_PHI]   = M_PHI;
+    var_values[VAR_E]     = M_E;
+    var_values[VAR_IN_W]  = var_values[VAR_IW] = inlink->w;
+    var_values[VAR_IN_H]  = var_values[VAR_IH] = inlink->h;
+    var_values[VAR_OUT_W] = var_values[VAR_OW] = NAN;
+    var_values[VAR_OUT_H] = var_values[VAR_OH] = NAN;
+    var_values[VAR_A]     = (double) inlink->w / inlink->h;
+    var_values[VAR_SAR]   = inlink->sample_aspect_ratio.num ?
+        (double) inlink->sample_aspect_ratio.num / inlink->sample_aspect_ratio.den : 1;
+    var_values[VAR_DAR]   = var_values[VAR_A] * var_values[VAR_SAR];
+
+    /* evaluate width and height */
+    av_expr_parse_and_eval(&res, (expr = s->w_expr),
+                           var_names, var_values,
+                           NULL, NULL, NULL, NULL, NULL, 0, ctx);
+    s->w = var_values[VAR_OUT_W] = var_values[VAR_OW] = res;
+    if ((ret = av_expr_parse_and_eval(&res, (expr = s->h_expr),
+                                      var_names, var_values,
+                                      NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
+        goto fail;
+    s->h = var_values[VAR_OUT_H] = var_values[VAR_OH] = res;
+    /* evaluate again the width, as it may depend on the output height */
+    if ((ret = av_expr_parse_and_eval(&res, (expr = s->w_expr),
+                                      var_names, var_values,
+                                      NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
+        goto fail;
+    s->w = res;
+
+    w = s->w;
+    h = s->h;
+
+    /* sanity check params */
+    if (w <  -1 || h <  -1) {
+        av_log(ctx, AV_LOG_ERROR, "Size values less than -1 are not acceptable.\n");
+        return AVERROR(EINVAL);
+    }
+    if (w == -1 && h == -1)
+        s->w = s->h = 0;
+
+    if (!(w = s->w))
+        w = inlink->w;
+    if (!(h = s->h))
+        h = inlink->h;
+    if (w == -1)
+        w = av_rescale(h, inlink->w, inlink->h);
+    if (h == -1)
+        h = av_rescale(w, inlink->h, inlink->w);
+
+    if (w > INT_MAX || h > INT_MAX ||
+        (h * inlink->w) > INT_MAX  ||
+        (w * inlink->h) > INT_MAX)
+        av_log(ctx, AV_LOG_ERROR, "Rescaled value for width or height is too big.\n");
+
+    outlink->w = w;
+    outlink->h = h;
+
+    ret = init_scale_session(ctx, inlink->w, inlink->h, w, h);
+    if (ret < 0)
+        return ret;
+
+    av_log(ctx, AV_LOG_VERBOSE, "w:%d h:%d -> w:%d h:%d\n",
+           inlink->w, inlink->h, outlink->w, outlink->h);
+
+    if (inlink->sample_aspect_ratio.num)
+        outlink->sample_aspect_ratio = av_mul_q((AVRational){outlink->h*inlink->w,
+                                                             outlink->w*inlink->h},
+                                                inlink->sample_aspect_ratio);
+    else
+        outlink->sample_aspect_ratio = inlink->sample_aspect_ratio;
+
+    return 0;
+
+fail:
+    av_log(NULL, AV_LOG_ERROR,
+           "Error when evaluating the expression '%s'\n", expr);
+    return ret;
+}
+
+static int qsvscale_filter_frame(AVFilterLink *link, AVFrame *in)
+{
+    AVFilterContext             *ctx = link->dst;
+    QSVScaleContext               *s = ctx->priv;
+    AVFilterLink            *outlink = ctx->outputs[0];
+
+    mfxSyncPoint sync = NULL;
+    mfxStatus err;
+
+    AVFrame *out = NULL;
+    int ret = 0;
+
+    out = av_frame_alloc();
+    if (!out) {
+        ret = AVERROR(ENOMEM);
+        goto fail;
+    }
+
+    ret = av_hwframe_get_buffer(s->out_frames_ref, out, 0);
+    if (ret < 0)
+        goto fail;
+
+    do {
+        err = MFXVideoVPP_RunFrameVPPAsync(s->session,
+                                           (mfxFrameSurface1*)in->data[3],
+                                           (mfxFrameSurface1*)out->data[3],
+                                           NULL, &sync);
+        if (err == MFX_WRN_DEVICE_BUSY)
+            av_usleep(1);
+    } while (err == MFX_WRN_DEVICE_BUSY);
+
+    if (err < 0 || !sync) {
+        av_log(ctx, AV_LOG_ERROR, "Error during scaling\n");
+        ret = AVERROR_UNKNOWN;
+        goto fail;
+    }
+
+    do {
+        err = MFXVideoCORE_SyncOperation(s->session, sync, 1000);
+    } while (err == MFX_WRN_IN_EXECUTION);
+    if (err < 0) {
+        av_log(ctx, AV_LOG_ERROR, "Error synchronizing the operation: %d\n", err);
+        ret = AVERROR_UNKNOWN;
+        goto fail;
+    }
+
+    ret = av_frame_copy_props(out, in);
+    if (ret < 0)
+        goto fail;
+
+    out->width  = outlink->w;
+    out->height = outlink->h;
+
+    av_reduce(&out->sample_aspect_ratio.num, &out->sample_aspect_ratio.den,
+              (int64_t)in->sample_aspect_ratio.num * outlink->h * link->w,
+              (int64_t)in->sample_aspect_ratio.den * outlink->w * link->h,
+              INT_MAX);
+
+    av_frame_free(&in);
+    return ff_filter_frame(outlink, out);
+fail:
+    av_frame_free(&in);
+    av_frame_free(&out);
+    return ret;
+}
+
+#define OFFSET(x) offsetof(QSVScaleContext, x)
+#define FLAGS AV_OPT_FLAG_VIDEO_PARAM
+static const AVOption options[] = {
+    { "w",      "Output video width",  OFFSET(w_expr),     AV_OPT_TYPE_STRING, { .str = "iw"   }, .flags = FLAGS },
+    { "h",      "Output video height", OFFSET(h_expr),     AV_OPT_TYPE_STRING, { .str = "ih"   }, .flags = FLAGS },
+    { "format", "Output pixel format", OFFSET(format_str), AV_OPT_TYPE_STRING, { .str = "same" }, .flags = FLAGS },
+
+    { NULL },
+};
+
+static const AVClass qsvscale_class = {
+    .class_name = "qsvscale",
+    .item_name  = av_default_item_name,
+    .option     = options,
+    .version    = LIBAVUTIL_VERSION_INT,
+};
+
+static const AVFilterPad qsvscale_inputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_VIDEO,
+        .filter_frame = qsvscale_filter_frame,
+    },
+    { NULL }
+};
+
+static const AVFilterPad qsvscale_outputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_VIDEO,
+        .config_props = qsvscale_config_props,
+    },
+    { NULL }
+};
+
+AVFilter ff_vf_scale_qsv = {
+    .name      = "scale_qsv",
+    .description = NULL_IF_CONFIG_SMALL("QuickSync video scaling and format conversion"),
+
+    .init          = qsvscale_init,
+    .uninit        = qsvscale_uninit,
+    .query_formats = qsvscale_query_formats,
+
+    .priv_size = sizeof(QSVScaleContext),
+    .priv_class = &qsvscale_class,
+
+    .inputs    = qsvscale_inputs,
+    .outputs   = qsvscale_outputs,
+};