libvpx: Pull from upstream

source/libvpx/examples/set_maps.c

 /*
  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 24 matching lines @@
 // is evenly divisble by 4, then the output will appear to have distinct
 // columns, where one column will have motion and the next will not.
 //
 // The active map is cleared on frame 44.
 //
 // Observing The Effects
 // ---------------------
 // Use the `simple_decoder` example to decode this sample, and observe
 // the change in the image at frames 22, 33, and 44.
 
+#include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
 #define VPX_CODEC_DISABLE_COMPAT 1
 #include "vpx/vp8cx.h"
 #include "vpx/vpx_encoder.h"
 
 #include "./tools_common.h"
 #include "./video_writer.h"
@@ skipping 115 matching lines @@
   const int fps = 2;        // TODO(dkovalev) add command line argument
   const double bits_per_pixel_per_frame = 0.067;
 
   exec_name = argv[0];
   if (argc != 6)
     die("Invalid number of arguments");
 
   memset(&info, 0, sizeof(info));
 
   encoder = get_vpx_encoder_by_name(argv[1]);
-  if (!encoder)
+  if (encoder == NULL) {
     die("Unsupported codec.");
-
+  }
+  assert(encoder != NULL);
   info.codec_fourcc = encoder->fourcc;
   info.frame_width = strtol(argv[2], NULL, 0);
   info.frame_height = strtol(argv[3], NULL, 0);
   info.time_base.numerator = 1;
   info.time_base.denominator = fps;
 
   if (info.frame_width <= 0 ||
       info.frame_height <= 0 ||
       (info.frame_width % 2) != 0 ||
       (info.frame_height % 2) != 0) {
@@ skipping 52 matching lines @@
   printf("Processed %d frames.\n", frame_count);
 
   vpx_img_free(&raw);
   if (vpx_codec_destroy(&codec))
     die_codec(&codec, "Failed to destroy codec.");
 
   vpx_video_writer_close(writer);
 
   return EXIT_SUCCESS;
 }