[FFmpeg-devel] [PATCH] avfilter/vf_bwdif: Add capability to deinterlace NV12

[John Cox]

As bwdif takes no account of horizontally adjacent pixels the same
code can be used on planes that have multiple components as is used
on single component planes. Update the filtering code to cope with
multi-component planes and add NV12 to the list of supported formats.

Signed-off-by: John Cox <jc at kynesim.co.uk>
---
 libavfilter/vf_bwdif.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/libavfilter/vf_bwdif.c b/libavfilter/vf_bwdif.c
index 353cd0b61a..e07783ff70 100644
--- a/libavfilter/vf_bwdif.c
+++ b/libavfilter/vf_bwdif.c
@@ -115,19 +115,28 @@ static void filter(AVFilterContext *ctx, AVFrame *dstpic,
     YADIFContext *yadif = &bwdif->yadif;
     ThreadData td = { .frame = dstpic, .parity = parity, .tff = tff };
     int i;
+    int last_plane = -1;
 
     for (i = 0; i < yadif->csp->nb_components; i++) {
         int w = dstpic->width;
         int h = dstpic->height;
+        const AVComponentDescriptor * const comp = yadif->csp->comp + i;
+
+        // If the last plane was the same as this plane assume we've dealt
+        // with all the pels already
+        if (last_plane == comp->plane)
+            continue;
+        last_plane = comp->plane;
 
         if (i == 1 || i == 2) {
             w = AV_CEIL_RSHIFT(w, yadif->csp->log2_chroma_w);
             h = AV_CEIL_RSHIFT(h, yadif->csp->log2_chroma_h);
         }
 
-        td.w     = w;
-        td.h     = h;
-        td.plane = i;
+        // comp step is in bytes but td.w is in pels
+        td.w       = w * comp->step / ((comp->depth + 7) / 8);
+        td.h       = h;
+        td.plane   = comp->plane;
 
         ff_filter_execute(ctx, filter_slice, &td, NULL,
                           FFMIN((h+3)/4, ff_filter_get_nb_threads(ctx)));
@@ -162,6 +171,7 @@ static const enum AVPixelFormat pix_fmts[] = {
     AV_PIX_FMT_YUVA420P9, AV_PIX_FMT_YUVA422P9, AV_PIX_FMT_YUVA444P9,
     AV_PIX_FMT_YUVA420P10, AV_PIX_FMT_YUVA422P10, AV_PIX_FMT_YUVA444P10,
     AV_PIX_FMT_YUVA420P16, AV_PIX_FMT_YUVA422P16, AV_PIX_FMT_YUVA444P16,
+    AV_PIX_FMT_NV12,
     AV_PIX_FMT_GBRP, AV_PIX_FMT_GBRP9, AV_PIX_FMT_GBRP10,
     AV_PIX_FMT_GBRP12, AV_PIX_FMT_GBRP14, AV_PIX_FMT_GBRP16,
     AV_PIX_FMT_GBRAP, AV_PIX_FMT_GBRAP16,
-- 
2.40.1