diff --git a/doc/general.texi b/doc/general.texi
index 5f27bac5e53ce39dbd4ef39edff9c028aab8f3a0..9db065fb44b6869e0705a52542b90aefd7e6c247 100644
--- a/doc/general.texi
+++ b/doc/general.texi
@@ -218,7 +218,7 @@ following image formats are supported:
@tab fourcc: CLJR
@item Creative YUV @tab @tab X
@tab fourcc: CYUV
-@item Dirac @tab X @tab X
+@item Dirac @tab E @tab E
@tab supported through external libdirac/libschroedinger libraries
@item Duck TrueMotion v1 @tab @tab X
@tab fourcc: DUCK
@@ -241,7 +241,7 @@ following image formats are supported:
@item H.261 @tab X @tab X
@item H.263(+) @tab X @tab X
@tab also known as RealVideo 1.0
-@item H.264 @tab @tab X
+@item H.264 @tab E @tab X
@tab encoding supported through external library libx264
@item HuffYUV @tab X @tab X
@item IBM Ultimotion @tab @tab X
@@ -304,7 +304,7 @@ following image formats are supported:
@tab fourcc: SP5X
@item TechSmith Camtasia @tab @tab X
@tab fourcc: TSCC
-@item Theora @tab X @tab X
+@item Theora @tab E @tab X
@tab encoding supported through external library libtheora
@item THP @tab @tab X
@tab Used on the Nintendo GameCube.
@@ -331,18 +331,20 @@ following image formats are supported:
@code{X} means that encoding (resp. decoding) is supported.
+@code{E} means that support is provided through an external library.
+
@section Audio Codecs
@multitable @columnfractions .4 .1 .1 .1 .7
@item Name @tab Encoding @tab Decoding @tab Comments
@item 4X IMA ADPCM @tab @tab X
@item 8SVX audio @tab @tab X
-@item AAC @tab X @tab X
+@item AAC @tab E @tab X
@tab encoding supported through external library libfaac
@item AC-3 @tab IX @tab IX
-@item AMR-NB @tab X @tab X
+@item AMR-NB @tab E @tab E
@tab supported through external library libamrnb
-@item AMR-WB @tab X @tab X
+@item AMR-WB @tab E @tab E
@tab supported through external library libamrwb
@item AMV IMA ADPCM @tab @tab X
@tab Used in AMV files
@@ -370,9 +372,9 @@ following image formats are supported:
@item Enhanced AC-3 @tab @tab X
@item FLAC lossless audio @tab IX @tab X
@item G.726 ADPCM @tab X @tab X
-@item GSM @tab X @tab X
+@item GSM @tab E @tab E
@tab supported through external library libgsm
-@item GSM_MS @tab X @tab X
+@item GSM_MS @tab E @tab E
@tab supported through external library libgsm
@item id RoQ DPCM @tab X @tab X
@tab Used in Quake III, Jedi Knight 2, other computer games.
@@ -386,7 +388,7 @@ following image formats are supported:
@tab Used in DVD-Audio and Blu-Ray discs.
@item Monkey's Audio @tab @tab X
@tab Only versions 3.97-3.99 are supported.
-@item MPEG audio layer 1/3 @tab X @tab IX
+@item MPEG audio layer 1/3 @tab E @tab IX
@tab MP3 encoding supported through external library LAME
@item MPEG audio layer 2 @tab IX @tab IX
@item MS IMA ADPCM @tab X @tab X
@@ -414,7 +416,7 @@ following image formats are supported:
@tab experimental codec
@item Sonic lossless @tab X @tab X
@tab experimental codec
-@item Speex @tab @tab X
+@item Speex @tab @tab E
@tab supported through external library libspeex
@item THP ADPCM @tab @tab X
@tab Used on the Nintendo GameCube.
@@ -430,6 +432,8 @@ following image formats are supported:
@code{X} means that encoding (resp. decoding) is supported.
+@code{E} means that support is provided through an external library.
+
@code{I} means that an integer-only version is available, too (ensures high
performance on systems without hardware floating point support).