From f07a8b13f38bbd52d55c52d1d6ea1265b13c7a84 Mon Sep 17 00:00:00 2001
From: Paul B Mahol <onemda@gmail.com>
Date: Thu, 21 Jan 2021 13:26:17 +0100
Subject: [PATCH] avfilter/vf_super2xsai: add slice threading support

---
 libavfilter/vf_super2xsai.c | 60 +++++++++++++++++++++++--------------
 1 file changed, 38 insertions(+), 22 deletions(-)

diff --git a/libavfilter/vf_super2xsai.c b/libavfilter/vf_super2xsai.c
index 4233f02388..d6c5f44c17 100644
--- a/libavfilter/vf_super2xsai.c
+++ b/libavfilter/vf_super2xsai.c
@@ -46,6 +46,10 @@ typedef struct Super2xSaIContext {
     int is_be;
 } Super2xSaIContext;
 
+typedef struct ThreadData {
+    AVFrame *in, *out;
+} ThreadData;
+
 #define GET_RESULT(A, B, C, D) ((A != C || A != D) - (B != C || B != D))
 
 #define INTERPOLATE(A, B) (((A & hi_pixel_mask) >> 1) + ((B & hi_pixel_mask) >> 1) + (A & B & lo_pixel_mask))
@@ -53,12 +57,18 @@ typedef struct Super2xSaIContext {
 #define Q_INTERPOLATE(A, B, C, D) ((A & q_hi_pixel_mask) >> 2) + ((B & q_hi_pixel_mask) >> 2) + ((C & q_hi_pixel_mask) >> 2) + ((D & q_hi_pixel_mask) >> 2) \
     + ((((A & q_lo_pixel_mask) + (B & q_lo_pixel_mask) + (C & q_lo_pixel_mask) + (D & q_lo_pixel_mask)) >> 2) & q_lo_pixel_mask)
 
-static void super2xsai(AVFilterContext *ctx,
-                       const uint8_t *src, int src_linesize,
-                       uint8_t *dst, int dst_linesize,
-                       int width, int height)
+static int super2xsai(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
 {
     Super2xSaIContext *s = ctx->priv;
+    ThreadData *td = arg;
+    AVFrame *in = td->in;
+    AVFrame *out = td->out;
+    const uint8_t *src = in->data[0];
+    uint8_t *dst = out->data[0];
+    const int src_linesize = in->linesize[0];
+    const int dst_linesize = out->linesize[0];
+    const int width = in->width;
+    const int height = in->height;
     unsigned int x, y;
     uint32_t color[4][4];
     const uint8_t *src_line[4];
@@ -67,18 +77,20 @@ static void super2xsai(AVFilterContext *ctx,
     const uint32_t lo_pixel_mask = s->lo_pixel_mask;
     const uint32_t q_hi_pixel_mask = s->q_hi_pixel_mask;
     const uint32_t q_lo_pixel_mask = s->q_lo_pixel_mask;
+    const int slice_start = (height * jobnr) / nb_jobs;
+    const int slice_end = (height * (jobnr+1)) / nb_jobs;
 
     /* Point to the first 4 lines, first line is duplicated */
-    src_line[0] = src;
-    src_line[1] = src;
-    src_line[2] = src + src_linesize*FFMIN(1, height-1);
-    src_line[3] = src + src_linesize*FFMIN(2, height-1);
+    src_line[0] = src + src_linesize*FFMAX(slice_start - 1, 0);
+    src_line[1] = src + src_linesize*slice_start;
+    src_line[2] = src + src_linesize*FFMIN(slice_start + 1, height-1);
+    src_line[3] = src + src_linesize*FFMIN(slice_start + 2, height-1);
 
 #define READ_COLOR4(dst, src_line, off) dst = *((const uint32_t *)src_line + off)
 #define READ_COLOR3(dst, src_line, off) dst = AV_RL24 (src_line + 3*off)
 #define READ_COLOR2(dst, src_line, off) dst = s->is_be ? AV_RB16(src_line + 2 * off) : AV_RL16(src_line + 2 * off)
 
-    for (y = 0; y < height; y++) {
+    for (y = slice_start; y < slice_end; y++) {
         uint8_t *dst_line[2];
 
         dst_line[0] = dst + dst_linesize*2*y;
@@ -229,6 +241,8 @@ static void super2xsai(AVFilterContext *ctx,
         if (y < height - 3)
             src_line[3] += src_linesize;
     } // y loop
+
+    return 0;
 }
 
 static int query_formats(AVFilterContext *ctx)
@@ -305,24 +319,25 @@ static int config_output(AVFilterLink *outlink)
     return 0;
 }
 
-static int filter_frame(AVFilterLink *inlink, AVFrame *inpicref)
+static int filter_frame(AVFilterLink *inlink, AVFrame *in)
 {
-    AVFilterLink *outlink = inlink->dst->outputs[0];
-    AVFrame *outpicref = ff_get_video_buffer(outlink, outlink->w, outlink->h);
-    if (!outpicref) {
-        av_frame_free(&inpicref);
+    AVFilterContext *ctx = inlink->dst;
+    AVFilterLink *outlink = ctx->outputs[0];
+    ThreadData td;
+    AVFrame *out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
+    if (!out) {
+        av_frame_free(&in);
         return AVERROR(ENOMEM);
     }
-    av_frame_copy_props(outpicref, inpicref);
-    outpicref->width  = outlink->w;
-    outpicref->height = outlink->h;
+    av_frame_copy_props(out, in);
+    out->width  = outlink->w;
+    out->height = outlink->h;
 
-    super2xsai(inlink->dst, inpicref->data[0], inpicref->linesize[0],
-               outpicref->data[0], outpicref->linesize[0],
-               inlink->w, inlink->h);
+    td.in = in, td.out = out;
+    ctx->internal->execute(ctx, super2xsai, &td, NULL, FFMIN(in->height, ff_filter_get_nb_threads(ctx)));
 
-    av_frame_free(&inpicref);
-    return ff_filter_frame(outlink, outpicref);
+    av_frame_free(&in);
+    return ff_filter_frame(outlink, out);
 }
 
 static const AVFilterPad super2xsai_inputs[] = {
@@ -351,4 +366,5 @@ AVFilter ff_vf_super2xsai = {
     .query_formats = query_formats,
     .inputs        = super2xsai_inputs,
     .outputs       = super2xsai_outputs,
+    .flags         = AVFILTER_FLAG_SLICE_THREADS,
 };