Merge pull request #4 from svt/10-bit-alt-2

10 bit support

Author: fhermansson

README.md

@@ -27,6 +27,10 @@ filter doesn't need any specific configuration.
 
 Only `AV_PIX_FMT_BGRA` is used right now since that's what we need.
 
+It is possible though, to preserve 10 bit colors using the `clear` param in combination with FFmpegs split and overlay filters:
+
+`-filter_complex "split=2[main][over1];[over1]proxy=clear=1:<other proxy params>[over2];[main][over2]overlay=format=yuv420p10`
+
 ## License
 
 Copyright 2020 Sveriges Television AB.

vf_proxy.c

@@ -13,6 +13,7 @@
 #include "libavutil/avassert.h"
 #include "libavutil/avstring.h"
 #include "libavutil/imgutils.h"
+#include "libavutil/intreadwrite.h"
 #include "libavutil/opt.h"
 #include "libavutil/parseutils.h"
 #include "video.h"
@@ -21,6 +22,7 @@ typedef struct {
   const AVClass* class;
   char* filter_path;
   char* config;
+  int clear;
   void* handle;
   void* user_data;
   int (*filter_init)(const char*, void**);
@@ -109,6 +111,14 @@ static int query_formats(AVFilterContext* ctx) {
   return ff_set_common_formats(ctx, fmts_list);
 }
 
+static void clear_image(AVFrame* out) {
+  for (int i = 0; i < out->height; i++) {
+    for (int j = 0; j < out->width; j++) {
+      AV_WN32(out->data[0] + i * out->linesize[0] + j * 4, 0);
+    }
+  }
+}
+
 static int filter_frame(AVFilterLink* inlink, AVFrame* in) {
   AVFilterContext* ctx = inlink->dst;
   AVFilterLink* outlink = ctx->outputs[0];
@@ -139,6 +149,10 @@ static int filter_frame(AVFilterLink* inlink, AVFrame* in) {
     return data_size;
   }
 
+  if (pc->clear) {
+    clear_image(out);
+  }
+
   double time_ms = in->pts * av_q2d(inlink->time_base) * 1000;
 
   int rc = pc->filter_frame(out->data[0], data_size, in->width, in->height,
@@ -192,6 +206,14 @@ static const AVOption proxy_options[] = {
      CHAR_MIN,
      CHAR_MAX,
      FLAGS},
+    {"clear",
+     "clear frame before filtering",
+     OFFSET(clear),
+     AV_OPT_TYPE_BOOL,
+     {.i64 = 0},
+     0,
+     1,
+     FLAGS},
     {NULL},
 };