diff --git a/libavformat/aiff.c b/libavformat/aiff.c
index 7bbaaed647a253006010d45f7b0d026f649ca04c..914c3a73b864dd30cf4b1f144adab341a5e9012c 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 669f087e8d4732fc86f55376108391305e164d44..3ef67507f41df7d4a0d0f2597c39eba346f0e8c8 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 33ae66ce8912e9671c31715bb025047eaa25515a..712c41911fd47c687304a9f8a07e5148da71057f 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 5acedcf519677ff9855db78c18b0c1d87a188dbc..27c7cdc850b13f04e6104ce3754c0da22f566e00 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 21544c7731b2fe25d437803fa7e09dbeb2915809..6511595616ead8acb5e4bceb1da9abed2d180a6c 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 08cd8513ac3b9778c45dfa15c822dc5106ba73c9..d893c5ab327ed1d88085ab7774eb1c58fd95b041 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 4d7a179fa7acb1554d79676a168a163e428f1d2f..ec81b7b1ce0d61790434f622b530f19c824cbda3 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 0684ce9eccc532b45381508541d43c78158a5df2..b94452c18fc395433bc4d83ac99eedf194e4e6d3 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 67179221681a80194083f3438db7df7df20aa9a8..a1c2aa4eb21df8c15219409be90298bfe4c1620e 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 3a27895b9cf07920150085dac41616a7a54d9e60..4be6b7051a38caa86a39d140df5ee88efc067de7 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 8c6b027dc4692a8ff24817d6533666e325edeced..03dc6dc265359e57c97c80b38d04575d6e936f11 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 99a36be8abe77f090dd4865f0648699b035eb140..c70d3d942c5fec3cdf6f330e28c3c8c3fd75f582 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 b5a4261d5276cde451ffce7bf4ee180ee89e253c..4b1b95a7ac56907d220073b3161514db8707b17f 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 169373e767c3c187e1e8b9487abc37fa0c23c2ab..ddb19088c64e30090a0e09da35aa6678b25d45b7 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 f69208bae181a418b5a52e77e23d19ff597e40e8..582e7e85476d861ded9eee653135c8c21756e4ca 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 ed0aae3830950e5363938596f16eb1ad99674f24..3607083d16cebda719c7e042eeb455b2c337f731 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 1b160679d98704f0f55b3a1faeb9d2eef1681967..9f46e1ae0c8d0fbc8407b3c740fdee78d3f4b8cf 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 257c10d0a177f7f60f1262708e09bb8a96c0419b..39868bea48b6fa46795011640e128ce7f610893d 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 5d0aa18f042088c50ec1bdf7685ab0cd0964d010..f26a2d2d586166a9596329f3c62381d17b5cd493 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 47e996ea3b2ecef045c336d919173505683d2163..bb706376ac67626b25d48c650918dd1ccf36f506 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 28b4a6dcd2e737860f5e0d2df954efc48c29fc42..16760236719e0a64c8468ec6d4b1314e0223449c 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 990837fa23556cac0158c362afb194c1acdab75b..a08bd2d9f120dd3fa12025ebbf13c1606922756f 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 84c5ee40cf821f1d1ea073f306a3396fd167fb62..20e45f75d2dda1329f621244cba67e1d17584b30 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 4a38362a1286a1d7f1981bb1dcd81e147c7ad4f6..7fb98234982950f50bddc29313349de111c6bc07 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.