diff --git a/libavformat/avio.c b/libavformat/avio.c
index 936a3d979c..2d587b349a 100644
--- a/libavformat/avio.c
+++ b/libavformat/avio.c
@@ -307,7 +307,7 @@ int ffurl_write(URLContext *h, const unsigned char *buf, int size)
     if (h->max_packet_size && size > h->max_packet_size)
         return AVERROR(EIO);
 
-    return retry_transfer_wrapper(h, buf, size, size, h->prot->url_write);
+    return retry_transfer_wrapper(h, buf, size, size, (void*)h->prot->url_write);
 }
 
 int64_t ffurl_seek(URLContext *h, int64_t pos, int whence)
diff --git a/libavformat/aviobuf.c b/libavformat/aviobuf.c
index 71406e0523..9c17e8c6e6 100644
--- a/libavformat/aviobuf.c
+++ b/libavformat/aviobuf.c
@@ -853,7 +853,7 @@ int ffio_fdopen(AVIOContext **s, URLContext *h)
 
     if (ffio_init_context(*s, buffer, buffer_size,
                       h->flags & AVIO_FLAG_WRITE, h,
-                      ffurl_read, ffurl_write, ffurl_seek) < 0) {
+                      (void*)ffurl_read, (void*)ffurl_write, (void*)ffurl_seek) < 0) {
         av_free(buffer);
         av_freep(s);
         return AVERROR(EIO);
diff --git a/libavformat/mpegenc.c b/libavformat/mpegenc.c
index 0c86df1eea..e42fac4ceb 100644
--- a/libavformat/mpegenc.c
+++ b/libavformat/mpegenc.c
@@ -923,7 +923,7 @@ static int flush_packet(AVFormatContext *ctx, int stream_index,
 
         /* output data */
         assert(payload_size - stuffing_size <= av_fifo_size(stream->fifo));
-        av_fifo_generic_read(stream->fifo, ctx->pb, payload_size - stuffing_size, &avio_write);
+        av_fifo_generic_read(stream->fifo, ctx->pb, payload_size - stuffing_size, (void*)avio_write);
         stream->bytes_to_iframe -= payload_size - stuffing_size;
     }else{
         payload_size=
diff --git a/libavformat/swfenc.c b/libavformat/swfenc.c
index f5328d0d9d..09c2d61f28 100644
--- a/libavformat/swfenc.c
+++ b/libavformat/swfenc.c
@@ -421,7 +421,7 @@ static int swf_write_video(AVFormatContext *s,
         put_swf_tag(s, TAG_STREAMBLOCK | TAG_LONG);
         avio_wl16(pb, swf->sound_samples);
         avio_wl16(pb, 0); // seek samples
-        av_fifo_generic_read(swf->audio_fifo, pb, frame_size, &avio_write);
+        av_fifo_generic_read(swf->audio_fifo, pb, frame_size, (void*)avio_write);
         put_swf_end_tag(s);
 
         /* update FIFO */