diff --git a/libavcodec/avcodec.c b/libavcodec/avcodec.c
index a85d3c2309..1af8a5937f 100644
--- a/libavcodec/avcodec.c
+++ b/libavcodec/avcodec.c
@@ -38,9 +38,16 @@
  #include "codec_internal.h"
  #include "decode.h"
  #include "encode.h"
+
+#if CONFIG_FRAME_THREAD_ENCODER
  #include "frame_thread_encoder.h"
+#endif
+
  #include "internal.h"
+
+#if HAVE_THREADS
  #include "thread.h"
+#endif
   int avcodec_default_execute(AVCodecContext *c, int 
(*func)(AVCodecContext *c2, void *arg2), void *arg, int *ret, int count, 
int size)
  {
@@ -67,7 +74,7 @@ int avcodec_default_execute2(AVCodecContext *c, int 
(*func)(AVCodecContext *c2,
      emms_c();
      return 0;
  }
-
+#if HAVE_THREADS
  static AVMutex codec_mutex = AV_MUTEX_INITIALIZER;
   static void lock_avcodec(const FFCodec *codec)
@@ -81,6 +88,10 @@ static void unlock_avcodec(const FFCodec *codec)
      if (codec->caps_internal & FF_CODEC_CAP_NOT_INIT_THREADSAFE && 
codec->init)
          ff_mutex_unlock(&codec_mutex);
  }
+#else
+#define lock_avcodec(args)
+#define unlock_avcodec(args)
+#endif
   static int64_t get_bit_rate(AVCodecContext *ctx)
  {
@@ -297,8 +308,8 @@ FF_ENABLE_DEPRECATION_WARNINGS
          ret = ff_decode_preinit(avctx);
      if (ret < 0)
          goto free_and_end;
-
-    if (HAVE_THREADS && !avci->frame_thread_encoder) {
+#if HAVE_THREADS
+    if (!avci->frame_thread_encoder) {
          /* Frame-threaded decoders call FFCodec.init for their child 
contexts. */
          lock_avcodec(codec2);
          ret = ff_thread_init(avctx);
@@ -307,8 +318,11 @@ FF_ENABLE_DEPRECATION_WARNINGS
              goto free_and_end;
          }
      }
-    if (!HAVE_THREADS && !(codec2->caps_internal & 
FF_CODEC_CAP_AUTO_THREADS))
+#endif
+#if !HAVE_THREADS
+    if (!(codec2->caps_internal & FF_CODEC_CAP_AUTO_THREADS))
          avctx->thread_count = 1;
+#endif
       if (!(avctx->active_thread_type & FF_THREAD_FRAME) ||
          avci->frame_thread_encoder) {
@@ -403,10 +417,13 @@ void avcodec_flush_buffers(AVCodecContext *avctx)
      av_frame_unref(avci->buffer_frame);
      av_packet_unref(avci->buffer_pkt);
  -    if (HAVE_THREADS && avctx->active_thread_type & FF_THREAD_FRAME)
-        ff_thread_flush(avctx);
-    else if (ffcodec(avctx->codec)->flush)
-        ffcodec(avctx->codec)->flush(avctx);
+    if (!(HAVE_THREADS && avctx->active_thread_type & FF_THREAD_FRAME)) {
+        if (ffcodec(avctx->codec)->flush)
+            ffcodec(avctx->codec)->flush(avctx);
+    }
+#if HAVE_THREADS
+    else ff_thread_flush(avctx);
+#endif
  }
   void avsubtitle_free(AVSubtitle *sub)
@@ -440,13 +457,14 @@ av_cold int avcodec_close(AVCodecContext *avctx)
       if (avcodec_is_open(avctx)) {
          AVCodecInternal *avci = avctx->internal;
-
-        if (CONFIG_FRAME_THREAD_ENCODER &&
-            avci->frame_thread_encoder && avctx->thread_count > 1) {
+#if CONFIG_FRAME_THREAD_ENCODER
+        if (avci->frame_thread_encoder && avctx->thread_count > 1)
              ff_frame_thread_encoder_free(avctx);
-        }
-        if (HAVE_THREADS && avci->thread_ctx)
+#endif
+#if HAVE_THREADS
+        if (avci->thread_ctx)
              ff_thread_free(avctx);
+#endif
          if (avci->needs_close && ffcodec(avctx->codec)->close)
              ffcodec(avctx->codec)->close(avctx);
          avci->byte_buffer_size = 0;
diff --git a/libavcodec/decode.c b/libavcodec/decode.c
index 6be2d3d6ed..2014c90d06 100644
--- a/libavcodec/decode.c
+++ b/libavcodec/decode.c
@@ -47,7 +47,10 @@
  #include "decode.h"
  #include "hwconfig.h"
  #include "internal.h"
+
+#if HAVE_THREADS
  #include "thread.h"
+#endif
   static int apply_param_change(AVCodecContext *avctx, const AVPacket 
*avpkt)
  {
@@ -301,9 +304,7 @@ static inline int 
decode_simple_internal(AVCodecContext *avctx, AVFrame *frame,
       got_frame = 0;
  -    if (HAVE_THREADS && avctx->active_thread_type & FF_THREAD_FRAME) {
-        ret = ff_thread_decode_frame(avctx, frame, &got_frame, pkt);
-    } else {
+    if (!(HAVE_THREADS && avctx->active_thread_type & FF_THREAD_FRAME)) {
          ret = codec->cb.decode(avctx, frame, &got_frame, pkt);
           if (!(codec->caps_internal & FF_CODEC_CAP_SETS_PKT_DTS))
@@ -321,6 +322,9 @@ static inline int 
decode_simple_internal(AVCodecContext *avctx, AVFrame *frame,
              }
          }
      }
+#if HAVE_THREADS
+    else ret = ff_thread_decode_frame(avctx, frame, &got_frame, pkt);
+#endif
      emms_c();
      actual_got_frame = got_frame;
  diff --git a/libavcodec/encode.c b/libavcodec/encode.c
index fbe2c97cd6..35d5bd281c 100644
--- a/libavcodec/encode.c
+++ b/libavcodec/encode.c
@@ -29,7 +29,11 @@
  #include "avcodec.h"
  #include "codec_internal.h"
  #include "encode.h"
+
+#if CONFIG_FRAME_THREAD_ENCODER
  #include "frame_thread_encoder.h"
+#endif
+
  #include "internal.h"
   int ff_alloc_packet(AVCodecContext *avctx, AVPacket *avpkt, int64_t size)
@@ -270,16 +274,19 @@ static int encode_simple_internal(AVCodecContext 
*avctx, AVPacket *avpkt)
       av_assert0(codec->cb_type == FF_CODEC_CB_TYPE_ENCODE);
  -    if (CONFIG_FRAME_THREAD_ENCODER && avci->frame_thread_encoder)
-        /* This will unref frame. */
-        ret = ff_thread_video_encode_frame(avctx, avpkt, frame, 
&got_packet);
-    else {
+    if (!(CONFIG_FRAME_THREAD_ENCODER && avci->frame_thread_encoder)) {
          ret = ff_encode_encode_cb(avctx, avpkt, frame, &got_packet);
  #if FF_API_THREAD_SAFE_CALLBACKS
          if (frame)
              av_frame_unref(frame);
  #endif
      }
+#if CONFIG_FRAME_THREAD_ENCODER
+    else {
+        /* This will unref frame. */
+        ret = ff_thread_video_encode_frame(avctx, avpkt, frame, 
&got_packet);
+    }
+#endif
       if (avci->draining && !got_packet)
          avci->draining_done = 1;
@@ -670,11 +677,11 @@ int ff_encode_preinit(AVCodecContext *avctx)
              return AVERROR(ENOMEM);
      }
  -    if (CONFIG_FRAME_THREAD_ENCODER) {
+#if CONFIG_FRAME_THREAD_ENCODER
          ret = ff_frame_thread_encoder_init(avctx);
          if (ret < 0)
              return ret;
-    }
+#endif
       return 0;
  }
diff --git a/libavcodec/h264dec.c b/libavcodec/h264dec.c
index 6ede4e8c9f..4538974dab 100644
--- a/libavcodec/h264dec.c
+++ b/libavcodec/h264dec.c
@@ -933,13 +933,13 @@ static int finalize_frame(H264Context *h, AVFrame 
*dst, H264Picture *out, int *g
           *got_frame = 1;
  -        if (CONFIG_MPEGVIDEODEC) {
-            ff_print_debug_info2(h->avctx, dst, NULL,
-                                 out->mb_type,
-                                 out->qscale_table,
-                                 out->motion_val,
-                                 out->mb_width, out->mb_height, 
out->mb_stride, 1);
-        }
+#if CONFIG_MPEGVIDEODEC
+        ff_print_debug_info2(h->avctx, dst, NULL,
+                             out->mb_type,
+                             out->qscale_table,
+                             out->motion_val,
+                             out->mb_width, out->mb_height, 
out->mb_stride, 1);
+#endif
      }
       return 0;
