set the encode parameter ultrafast

@@ -216,7 +216,7 @@ int CAVTranscoder::open_output_file(const char *filename)
 			enc_ctx->flags |= CODEC_FLAG_GLOBAL_HEADER;
 
 		if (0 == i) {
-			encoder = avcodec_find_encoder(AV_CODEC_ID_H264);;
+			encoder = avcodec_find_encoder(AV_CODEC_ID_H264);
 			if (!encoder) {
 				av_log(NULL, AV_LOG_FATAL, "Necessary encoder not found\n");
 				return AVERROR_INVALIDDATA;
@@ -235,21 +235,21 @@ int CAVTranscoder::open_output_file(const char *filename)
 				enc_ctx->time_base.num = 1;
 				enc_ctx->time_base.den = 20;
 				enc_ctx->gop_size = 20;
-
+				
 				enc_ctx->me_range = 16;
 				enc_ctx->max_qdiff = 4;
 				enc_ctx->qmin = 10;
 				enc_ctx->qmax = 30;
 				enc_ctx->qcompress = 0.6f;
+				
 				enc_ctx->framerate.den = 20;
 				enc_ctx->framerate.num = 1;
+				enc_ctx->max_b_frames = 0;
 
-				AVDictionary * d = NULL;
-				char *k = av_strdup("preset");       // if your strings are already allocated,
-				char *v = av_strdup("ultrafast");    // you can avoid copying them like this
-				av_dict_set(&d, k, v, AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL);
-				/* Third parameter can be used to pass settings to encoder */
-				ret = avcodec_open2(enc_ctx, encoder, NULL);
+				AVDictionary * d = NULL;
+				av_dict_set(&d, "preset", "ultrafast", 0);
+				/* Third parameter can be used to pass settings to encoder */
+				ret = avcodec_open2(enc_ctx, encoder, &d);
 				if (ret < 0) {
 					av_log(NULL, AV_LOG_ERROR, "Cannot open video encoder for stream #%u\n", i);
 					return ret;