diff --git a/src/cli.c b/src/cli.c
index ccfa2675..d53c0b95 100644
--- a/src/cli.c
+++ b/src/cli.c
@@ -57,6 +57,7 @@ static const struct option long_options[] = {
   { "tr-depth-intra",     required_argument, NULL, 0 },
   { "me",                 required_argument, NULL, 0 },
   { "subme",              required_argument, NULL, 0 },
+  { "source-scan-type",   required_argument, NULL, 0 },
   { "sar",                required_argument, NULL, 0 },
   { "overscan",           required_argument, NULL, 0 },
   { "videoformat",        required_argument, NULL, 0 },
@@ -284,6 +285,10 @@ void print_help(void)
     "          --cpuid <integer>      : Disable runtime cpu optimizations with value 0.\n"
     "          --subme <integer>      : Set fractional pixel motion estimation level [1].\n"
     "                                     0: only integer motion estimation\n"
+    "          --source-scan-type <string> : Set source scan type [\"progressive\"].\n"
+    "                                     \"progressive\": progressive scan\n"
+    "                                     \"tff\": top field first\n"
+    "                                     \"bff\": bottom field first\n"
     "                                     1: fractional pixel motion estimation enabled\n"
     "          --pu-depth-inter <int>-<int> : Range for sizes of inter prediction units to try.\n"
     "                                     0: 64x64, 1: 32x32, 2: 16x16, 3: 8x8\n"
diff --git a/src/config.c b/src/config.c
index 35be7532..5bc57c54 100644
--- a/src/config.c
+++ b/src/config.c
@@ -70,6 +70,7 @@ int config_init(kvz_config *cfg)
   cfg->tr_depth_intra  = 0;
   cfg->ime_algorithm   = 0; /* hexbs */
   cfg->fme_level       = 1;
+  cfg->source_scan_type = 0; /* progressive */
   cfg->vui.sar_width   = 0;
   cfg->vui.sar_height  = 0;
   cfg->vui.overscan    = 0; /* undef */
@@ -276,6 +277,7 @@ static int parse_slice_specification(const char* const arg, int32_t * const nsli
 int config_parse(kvz_config *cfg, const char *name, const char *value)
 {
   static const char * const me_names[]          = { "hexbs", "tz", NULL };
+  static const char * const source_scan_type_names[] = { "progressive", "tff", "bff", NULL };
 
   static const char * const overscan_names[]    = { "undef", "show", "crop", NULL };
   static const char * const videoformat_names[] = { "component", "pal", "ntsc", "secam", "mac", "undef", NULL };
@@ -356,6 +358,8 @@ int config_parse(kvz_config *cfg, const char *name, const char *value)
   }
   else if OPT("subme")
     cfg->fme_level = atoi(value);
+  else if OPT("source-scan-type")
+    return parse_enum(value, source_scan_type_names, &cfg->source_scan_type);
   else if OPT("sar")
     return sscanf(value, "%d:%d", &cfg->vui.sar_width, &cfg->vui.sar_height) == 2;
   else if OPT("overscan")
diff --git a/src/encoder.c b/src/encoder.c
index ef57340d..b01b300c 100644
--- a/src/encoder.c
+++ b/src/encoder.c
@@ -153,6 +153,8 @@ encoder_control_t* encoder_control_init(const kvz_config *const cfg) {
   // Rate-distortion optimization level
   encoder->rdo        = 1;
   encoder->full_intra_search = 0;
+  // INTERLACING
+  encoder->in.source_scan_type = (int8_t)cfg->source_scan_type;
 
   // Initialize the scaling list
   scalinglist_init(&encoder->scaling_list);
diff --git a/src/encoder.h b/src/encoder.h
index 81eebe1d..0411eccf 100644
--- a/src/encoder.h
+++ b/src/encoder.h
@@ -55,6 +55,7 @@ typedef struct encoder_control_t
     int8_t video_format;
     int8_t bitdepth;  /*!< \brief input bit depth (8,10) */
     int64_t pixels_per_pic;
+    int8_t source_scan_type;
   } in;
   
   /* TODO: add ME data */
diff --git a/src/kvazaar.h b/src/kvazaar.h
index 871d3622..8374a82e 100644
--- a/src/kvazaar.h
+++ b/src/kvazaar.h
@@ -112,6 +112,7 @@ typedef struct kvz_config
   int32_t tr_depth_intra; /*!< \brief Maximum transform depth for intra. */
   enum kvz_ime_algorithm ime_algorithm;  /*!< \brief Integer motion estimation algorithm. */
   int32_t fme_level;      /*!< \brief Fractional pixel motion estimation level (0: disabled, 1: enabled). */
+  int8_t source_scan_type; /*!< \brief Source scan type (0: progressive, 1: top field first, 2: bottom field first).*/
   int32_t bipred;         /*!< \brief Bi-prediction (0: disabled, 1: enabled). */
   int32_t deblock_beta;   /*!< \brief (deblocking) beta offset (div 2), range -6...6 */
   int32_t deblock_tc;     /*!< \brief (deblocking) tc offset (div 2), range -6...6 */
diff --git a/src/kvazaar_version.h b/src/kvazaar_version.h
index d1e87cd8..8c568647 100644
--- a/src/kvazaar_version.h
+++ b/src/kvazaar_version.h
@@ -21,6 +21,6 @@
 ****************************************************************************/
 
 // KVZ_API_VERSION is incremented every time the public api changes.
-#define KVZ_API_VERSION 1
+#define KVZ_API_VERSION 2
 
 #endif // KVAZAAR_VERSION_H_