nvenc: add "gop-size" property

This also changes the default gop size from 30 to 75 frames.

https://bugzilla.gnome.org/show_bug.cgi?id=781410

sys/nvenc/gstnvbaseenc.c

@@ -166,6 +166,7 @@ enum
   PROP_QP_MIN,
   PROP_QP_MAX,
   PROP_QP_CONST,
+  PROP_GOP_SIZE,
 };
 
 #define DEFAULT_PRESET GST_NV_PRESET_DEFAULT
@@ -174,6 +175,7 @@ enum
 #define DEFAULT_QP_MIN -1
 #define DEFAULT_QP_MAX -1
 #define DEFAULT_QP_CONST -1
+#define DEFAULT_GOP_SIZE 75
 
 /* This lock is needed to prevent the situation where multiple encoders are
  * initialised at the same time which appears to cause excessive CPU usage over
@@ -284,6 +286,12 @@ gst_nv_base_enc_class_init (GstNvBaseEncClass * klass)
           DEFAULT_QP_CONST,
           G_PARAM_READWRITE | GST_PARAM_MUTABLE_PLAYING |
           G_PARAM_STATIC_STRINGS));
+  g_object_class_install_property (gobject_class, PROP_GOP_SIZE,
+      g_param_spec_int ("gop-size", "GOP size",
+          "Number of frames between intra frames (-1 = infinite)",
+          -1, G_MAXINT, DEFAULT_GOP_SIZE,
+          (GParamFlags) (G_PARAM_READWRITE | GST_PARAM_MUTABLE_PLAYING |
+              G_PARAM_STATIC_STRINGS)));
   g_object_class_install_property (gobject_class, PROP_BITRATE,
       g_param_spec_uint ("bitrate", "Bitrate",
           "Bitrate in kbit/sec (0 = from NVENC preset)", 0, 2000 * 1024,
@@ -661,6 +669,7 @@ gst_nv_base_enc_init (GstNvBaseEnc * nvenc)
   nvenc->qp_max = DEFAULT_QP_MAX;
   nvenc->qp_const = DEFAULT_QP_CONST;
   nvenc->bitrate = DEFAULT_BITRATE;
+  nvenc->gop_size = DEFAULT_GOP_SIZE;
 
   GST_VIDEO_ENCODER_STREAM_LOCK (encoder);
   GST_VIDEO_ENCODER_STREAM_UNLOCK (encoder);
@@ -1193,6 +1202,13 @@ gst_nv_base_enc_set_format (GstVideoEncoder * enc, GstVideoCodecState * state)
     }
   }
 
+  if (nvenc->gop_size < 0) {
+    params->encodeConfig->gopLength = NVENC_INFINITE_GOPLENGTH;
+    params->encodeConfig->frameIntervalP = 1;
+  } else if (nvenc->gop_size > 0) {
+    params->encodeConfig->gopLength = nvenc->gop_size;
+  }
+
   g_assert (nvenc_class->set_encoder_config);
   if (!nvenc_class->set_encoder_config (nvenc, state, params->encodeConfig)) {
     GST_ERROR_OBJECT (enc, "Subclass failed to set encoder configuration");
@@ -1945,6 +1961,10 @@ gst_nv_base_enc_set_property (GObject * object, guint prop_id,
       nvenc->bitrate = g_value_get_uint (value);
       gst_nv_base_enc_schedule_reconfig (nvenc);
       break;
+    case PROP_GOP_SIZE:
+      nvenc->gop_size = g_value_get_int (value);
+      gst_nv_base_enc_schedule_reconfig (nvenc);
+      break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
@@ -1979,6 +1999,9 @@ gst_nv_base_enc_get_property (GObject * object, guint prop_id, GValue * value,
     case PROP_BITRATE:
       g_value_set_uint (value, nvenc->bitrate);
       break;
+    case PROP_GOP_SIZE:
+      g_value_set_int (value, nvenc->gop_size);
+      break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;

sys/nvenc/gstnvbaseenc.h

@@ -69,6 +69,7 @@ typedef struct {
   gint            qp_max;
   gint            qp_const;
   guint           bitrate;
+  gint            gop_size;
 
   CUcontext       cuda_ctx;
   void          * encoder;

sys/nvenc/gstnvh264enc.c

@@ -479,6 +479,8 @@ gst_nv_h264_enc_set_encoder_config (GstNvBaseEnc * nvenc,
     config->encodeCodecConfig.h264Config.chromaFormatIDC = 3;
   }
 
+  config->encodeCodecConfig.h264Config.idrPeriod = config->gopLength;
+
   /* FIXME: make property */
   config->encodeCodecConfig.h264Config.outputAUD = 1;