diff --git a/libavformat/aiff.c b/libavformat/aiff.c
index 7bbaaed647..914c3a73b8 100644
--- a/libavformat/aiff.c
+++ b/libavformat/aiff.c
@@ -1,5 +1,5 @@
 /*
- * AIFF/AIFF-C encoder and decoder
+ * AIFF/AIFF-C muxer and demuxer
  * Copyright (c) 2006  Patrick Guimond
  *
  * This file is part of FFmpeg.
diff --git a/libavformat/asf-enc.c b/libavformat/asf-enc.c
index 669f087e8d..3ef67507f4 100644
--- a/libavformat/asf-enc.c
+++ b/libavformat/asf-enc.c
@@ -1,5 +1,5 @@
 /*
- * Adaptive stream format encoder
+ * Adaptive stream format muxer
  * Copyright (c) 2000, 2001 Fabrice Bellard.
  *
  * This file is part of FFmpeg.
diff --git a/libavformat/asf.c b/libavformat/asf.c
index 33ae66ce89..712c41911f 100644
--- a/libavformat/asf.c
+++ b/libavformat/asf.c
@@ -1,5 +1,5 @@
 /*
- * ASF compatible decoder.
+ * ASF compatible demuxer
  * Copyright (c) 2000, 2001 Fabrice Bellard.
  *
  * This file is part of FFmpeg.
diff --git a/libavformat/au.c b/libavformat/au.c
index 5acedcf519..27c7cdc850 100644
--- a/libavformat/au.c
+++ b/libavformat/au.c
@@ -1,5 +1,5 @@
 /*
- * AU encoder and decoder
+ * AU muxer and demuxer
  * Copyright (c) 2001 Fabrice Bellard.
  *
  * This file is part of FFmpeg.
diff --git a/libavformat/avidec.c b/libavformat/avidec.c
index 21544c7731..6511595616 100644
--- a/libavformat/avidec.c
+++ b/libavformat/avidec.c
@@ -1,5 +1,5 @@
 /*
- * AVI decoder.
+ * AVI demuxer
  * Copyright (c) 2001 Fabrice Bellard.
  *
  * This file is part of FFmpeg.
diff --git a/libavformat/avienc.c b/libavformat/avienc.c
index 08cd8513ac..d893c5ab32 100644
--- a/libavformat/avienc.c
+++ b/libavformat/avienc.c
@@ -1,5 +1,5 @@
 /*
- * AVI encoder.
+ * AVI muxer
  * Copyright (c) 2000 Fabrice Bellard.
  *
  * This file is part of FFmpeg.
diff --git a/libavformat/daud.c b/libavformat/daud.c
index 4d7a179fa7..ec81b7b1ce 100644
--- a/libavformat/daud.c
+++ b/libavformat/daud.c
@@ -1,5 +1,5 @@
 /*
- * D-Cinema audio decoder.
+ * D-Cinema audio demuxer
  * Copyright (c) 2005 Reimar Döffinger.
  *
  * This file is part of FFmpeg.
diff --git a/libavformat/ffm.c b/libavformat/ffm.c
index 0684ce9ecc..b94452c18f 100644
--- a/libavformat/ffm.c
+++ b/libavformat/ffm.c
@@ -1,5 +1,5 @@
 /*
- * FFM (ffserver live feed) encoder and decoder
+ * FFM (ffserver live feed) muxer and demuxer
  * Copyright (c) 2001 Fabrice Bellard.
  *
  * This file is part of FFmpeg.
diff --git a/libavformat/flvdec.c b/libavformat/flvdec.c
index 6717922168..a1c2aa4eb2 100644
--- a/libavformat/flvdec.c
+++ b/libavformat/flvdec.c
@@ -1,5 +1,5 @@
 /*
- * FLV decoder.
+ * FLV demuxer
  * Copyright (c) 2003 The FFmpeg Project.
  *
  * This file is part of FFmpeg.
diff --git a/libavformat/flvenc.c b/libavformat/flvenc.c
index 3a27895b9c..4be6b7051a 100644
--- a/libavformat/flvenc.c
+++ b/libavformat/flvenc.c
@@ -1,5 +1,5 @@
 /*
- * FLV encoder.
+ * FLV muxer
  * Copyright (c) 2003 The FFmpeg Project.
  *
  * This file is part of FFmpeg.
diff --git a/libavformat/gif.c b/libavformat/gif.c
index 8c6b027dc4..03dc6dc265 100644
--- a/libavformat/gif.c
+++ b/libavformat/gif.c
@@ -1,5 +1,5 @@
 /*
- * Animated GIF encoder
+ * Animated GIF muxer
  * Copyright (c) 2000 Fabrice Bellard.
  *
  * This file is part of FFmpeg.
diff --git a/libavformat/gifdec.c b/libavformat/gifdec.c
index 99a36be8ab..c70d3d942c 100644
--- a/libavformat/gifdec.c
+++ b/libavformat/gifdec.c
@@ -1,5 +1,5 @@
 /*
- * GIF decoder
+ * GIF demuxer
  * Copyright (c) 2003 Fabrice Bellard.
  *
  * This file is part of FFmpeg.
diff --git a/libavformat/mov.c b/libavformat/mov.c
index b5a4261d52..4b1b95a7ac 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -1,5 +1,5 @@
 /*
- * MOV decoder.
+ * MOV demuxer
  * Copyright (c) 2001 Fabrice Bellard.
  *
  * This file is part of FFmpeg.
diff --git a/libavformat/movenc.c b/libavformat/movenc.c
index 169373e767..ddb19088c6 100644
--- a/libavformat/movenc.c
+++ b/libavformat/movenc.c
@@ -1,5 +1,5 @@
 /*
- * MOV, 3GP, MP4 encoder.
+ * MOV, 3GP, MP4 muxer
  * Copyright (c) 2003 Thomas Raivio.
  * Copyright (c) 2004 Gildas Bazin <gbazin at videolan dot org>.
  *
diff --git a/libavformat/mp3.c b/libavformat/mp3.c
index f69208bae1..582e7e8547 100644
--- a/libavformat/mp3.c
+++ b/libavformat/mp3.c
@@ -1,5 +1,5 @@
 /*
- * MP3 encoder and decoder
+ * MP3 muxer and demuxer
  * Copyright (c) 2003 Fabrice Bellard.
  *
  * This file is part of FFmpeg.
diff --git a/libavformat/mpeg.c b/libavformat/mpeg.c
index ed0aae3830..3607083d16 100644
--- a/libavformat/mpeg.c
+++ b/libavformat/mpeg.c
@@ -1,5 +1,5 @@
 /*
- * MPEG1/2 mux/demux
+ * MPEG1/2 muxer and demuxer
  * Copyright (c) 2000, 2001, 2002 Fabrice Bellard.
  *
  * This file is part of FFmpeg.
diff --git a/libavformat/mpegts.c b/libavformat/mpegts.c
index 1b160679d9..9f46e1ae0c 100644
--- a/libavformat/mpegts.c
+++ b/libavformat/mpegts.c
@@ -1,5 +1,5 @@
 /*
- * MPEG2 transport stream (aka DVB) demux
+ * MPEG2 transport stream (aka DVB) demuxer
  * Copyright (c) 2002-2003 Fabrice Bellard.
  *
  * This file is part of FFmpeg.
diff --git a/libavformat/mpegtsenc.c b/libavformat/mpegtsenc.c
index 257c10d0a1..39868bea48 100644
--- a/libavformat/mpegtsenc.c
+++ b/libavformat/mpegtsenc.c
@@ -1,5 +1,5 @@
 /*
- * MPEG2 transport stream (aka DVB) mux
+ * MPEG2 transport stream (aka DVB) muxer
  * Copyright (c) 2003 Fabrice Bellard.
  *
  * This file is part of FFmpeg.
diff --git a/libavformat/nsvdec.c b/libavformat/nsvdec.c
index 5d0aa18f04..f26a2d2d58 100644
--- a/libavformat/nsvdec.c
+++ b/libavformat/nsvdec.c
@@ -1,5 +1,5 @@
 /*
- * NSV decoder.
+ * NSV demuxer
  * Copyright (c) 2004 The FFmpeg Project.
  *
  * This file is part of FFmpeg.
diff --git a/libavformat/raw.c b/libavformat/raw.c
index 47e996ea3b..bb706376ac 100644
--- a/libavformat/raw.c
+++ b/libavformat/raw.c
@@ -1,5 +1,5 @@
 /*
- * RAW encoder and decoder
+ * RAW muxer and demuxer
  * Copyright (c) 2001 Fabrice Bellard.
  * Copyright (c) 2005 Alex Beregszaszi
  *
diff --git a/libavformat/rm.c b/libavformat/rm.c
index 28b4a6dcd2..1676023671 100644
--- a/libavformat/rm.c
+++ b/libavformat/rm.c
@@ -1,5 +1,5 @@
 /*
- * "Real" compatible mux and demux.
+ * "Real" compatible muxer and demuxer.
  * Copyright (c) 2000, 2001 Fabrice Bellard.
  *
  * This file is part of FFmpeg.
diff --git a/libavformat/smacker.c b/libavformat/smacker.c
index 990837fa23..a08bd2d9f1 100644
--- a/libavformat/smacker.c
+++ b/libavformat/smacker.c
@@ -1,5 +1,5 @@
 /*
- * Smacker decoder
+ * Smacker demuxer
  * Copyright (c) 2006 Konstantin Shishkov.
  *
  * This file is part of FFmpeg.
diff --git a/libavformat/sol.c b/libavformat/sol.c
index 84c5ee40cf..20e45f75d2 100644
--- a/libavformat/sol.c
+++ b/libavformat/sol.c
@@ -1,5 +1,5 @@
 /*
- * Sierra SOL decoder
+ * Sierra SOL demuxer
  * Copyright Konstantin Shishkov.
  *
  * This file is part of FFmpeg.
diff --git a/libavformat/wav.c b/libavformat/wav.c
index 4a38362a12..7fb9823498 100644
--- a/libavformat/wav.c
+++ b/libavformat/wav.c
@@ -1,5 +1,5 @@
 /*
- * WAV encoder and decoder
+ * WAV muxer and demuxer
  * Copyright (c) 2001, 2002 Fabrice Bellard.
  *
  * This file is part of FFmpeg.