Add a step-cutoff parameter for motion estimation search

README.md

@@ -137,6 +137,9 @@ Compression tools:
                                    - full:  Full Search
                                    - full8, full16, full32, full64
                                    - dia:   Diamond Search
+      --me-steps <integer>   : How many search steps does the motion estimation
+                               do before cutting off, -1 for no limits [-1]
+                                   Has effect only for 'hexbs' and 'dia'
       --subme <integer>      : Set fractional pixel motion estimation level
                                    - 0: only integer motion estimation
                                    - 1: + 1/2-pixel horizontal and vertical

src/cfg.c

@@ -130,6 +130,8 @@ int kvz_config_init(kvz_config *cfg)
   cfg->force_level = true; // don't care about level limits by-default
   cfg->high_tier = false;
 
+  cfg->me_max_steps = (uint32_t)-1;
+
   return 1;
 }
 
@@ -1153,6 +1155,9 @@ int kvz_config_parse(kvz_config *cfg, const char *name, const char *value)
   else if (OPT("high-tier")) {
     cfg->high_tier = true;
   }
+  else if (OPT("me-steps")) {
+    cfg->me_max_steps = (uint32_t)atoi(value); // fix
+  }
   else {
     return 0;
   }

src/cli.c

@@ -125,6 +125,7 @@ static const struct option long_options[] = {
   { "level",              required_argument, NULL, 0 },
   { "force-level",        required_argument, NULL, 0 },
   { "high-tier",                no_argument, NULL, 0 },
+  { "me-steps",           required_argument, NULL, 0 },
   {0, 0, 0, 0}
 };
 
@@ -431,6 +432,9 @@ void print_help(void)
     "                                   - full:  Full Search\n"
     "                                   - full8, full16, full32, full64\n"
     "                                   - dia:   Diamond Search\n"
+    "      --me-steps <integer>   : How many search steps does the motion estimation\n"
+    "                               do before cutting off, -1 for no limits [-1]\n"
+    "                                   Has effect only for 'hexbs' and 'dia'\n"
     "      --subme <integer>      : Set fractional pixel motion estimation level\n"
     "                                   - 0: only integer motion estimation\n"
     "                                   - 1: + 1/2-pixel horizontal and vertical\n"

src/kvazaar.h

@@ -361,6 +361,9 @@ typedef struct kvz_config
   uint8_t high_tier;
   /** \brief The maximum allowed bitrate for this level and tier. */
   uint32_t max_bitrate;
+
+  /** \brief Maximum steps that hexagonal and diagonal motion estimation can use. -1 to disable */
+  uint32_t me_max_steps;
 } kvz_config;
 
 /**

src/search_inter.c

@@ -640,7 +640,7 @@ static void tz_search(inter_search_info_t *info, vector2d_t extra_mv)
  * the predicted motion vector is way off. In the future even more additional
  * points like 0,0 might be used, such as vectors from top or left.
  */
-static void hexagon_search(inter_search_info_t *info, vector2d_t extra_mv)
+static void hexagon_search(inter_search_info_t *info, vector2d_t extra_mv, uint32_t max_steps)
 {
   // The start of the hexagonal pattern has been repeated at the end so that
   // the indices between 1-6 can be used as the start of a 3-point list of new
@@ -689,9 +689,14 @@ static void hexagon_search(inter_search_info_t *info, vector2d_t extra_mv)
     }
   }
 
+  uint32_t steps_left = max_steps;
+
   // Iteratively search the 3 new points around the best match, until the best
   // match is in the center.
-  while (best_index != 0) {
+  while (best_index != 0 && steps_left != 0) {
+    // decrement count if enabled
+    if (steps_left > 0 && max_steps != (uint32_t)-1) steps_left -= 1;
+
     // Starting point of the 3 offsets to be searched.
     unsigned start;
     if (best_index == 1) {
@@ -727,7 +732,7 @@ static void hexagon_search(inter_search_info_t *info, vector2d_t extra_mv)
 }
 
 
-static void diamond_search(inter_search_info_t *info, vector2d_t extra_mv)
+static void diamond_search(inter_search_info_t *info, vector2d_t extra_mv, uint32_t max_steps) 
 {
   enum diapos {
     DIA_UP = 0,
@@ -786,9 +791,12 @@ static void diamond_search(inter_search_info_t *info, vector2d_t extra_mv)
 
   // whether we found a better candidate this iteration
   uint8_t better_found;
+  uint32_t steps_left = max_steps;
 
   do {
     better_found = 0;
+    // decrement count if enabled
+    if (steps_left > 0 && max_steps != (uint32_t) -1) steps_left -= 1;
 
     // search the points of the diamond
     for (int i = 0; i < 4; ++i) {
@@ -810,7 +818,7 @@ static void diamond_search(inter_search_info_t *info, vector2d_t extra_mv)
       // the xor operation flips the orientation
       from_dir = best_index ^ 0x3;
     }
-  } while (better_found);
+  } while (better_found && steps_left != 0);
   // and we're done
 }
 
@@ -1250,11 +1258,11 @@ static void search_pu_inter_ref(inter_search_info_t *info,
       break;
 
     case KVZ_IME_DIA:
-      diamond_search(info, mv);
+      diamond_search(info, mv, info->state->encoder_control->cfg.me_max_steps);
       break;
 
     default:
-      hexagon_search(info, mv);
+      hexagon_search(info, mv, info->state->encoder_control->cfg.me_max_steps);
       break;
   }