diff --git a/NEWS b/NEWS
index a093ff0e7..73264e10f 100644
--- a/NEWS
+++ b/NEWS
@@ -1,4 +1,6 @@
 ver 0.22 (not yet released)
+* input
+  - ffmpeg: allow partial reads
 
 ver 0.21.6 (not yet released)
 * protocol
diff --git a/src/lib/ffmpeg/IOContext.hxx b/src/lib/ffmpeg/IOContext.hxx
index 95ce637ee..c2a3e3409 100644
--- a/src/lib/ffmpeg/IOContext.hxx
+++ b/src/lib/ffmpeg/IOContext.hxx
@@ -71,8 +71,8 @@ public:
 	}
 
 	size_t Read(void *buffer, size_t size) {
-		int result = avio_read(io_context,
-				       (unsigned char *)buffer, size);
+		int result = avio_read_partial(io_context,
+					       (unsigned char *)buffer, size);
 		if (result < 0)
 			throw MakeFfmpegError(result, "avio_read() failed");