[FFmpeg-cvslog] libspeexenc: Updated commentary to reflect recent changes

[Dmitry Samonenko]

ffmpeg | branch: master | Dmitry Samonenko <shreddingwork at gmail.com> | Fri Oct  5 00:42:31 2012 +0400| [f1c6a740fcb9ea0a977855bb708c0541149fa9cf] | committer: Martin Storsjö

libspeexenc: Updated commentary to reflect recent changes

Signed-off-by: Martin Storsjö <martin at martin.st>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=f1c6a740fcb9ea0a977855bb708c0541149fa9cf
---

 libavcodec/libspeexenc.c |   17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/libavcodec/libspeexenc.c b/libavcodec/libspeexenc.c
index 5a5079b..cbfa5be 100644
--- a/libavcodec/libspeexenc.c
+++ b/libavcodec/libspeexenc.c
@@ -62,6 +62,23 @@
  *     sometimes desirable to use multiple frames-per-packet to reduce the
  *     amount of container overhead.  This can be done by setting the
  *     'frames_per_packet' option to a value 1 to 8.
+ *
+ *
+ * Optional features
+ * Speex encoder supports several optional features, which can be useful
+ * for some conditions.
+ *
+ * Voice Activity Detection
+ *     When enabled, voice activity detection detects whether the audio
+ *     being encoded is speech or silence/background noise. VAD is always
+ *     implicitly activated when encoding in VBR, so the option is only useful
+ *     in non-VBR operation. In this case, Speex detects non-speech periods and
+ *     encodes them with just enough bits to reproduce the background noise.
+ *
+ * Discontinuous Transmission (DTX)
+ *     DTX is an addition to VAD/VBR operation, that allows to stop transmitting
+ *     completely when the background noise is stationary.
+ *     In file-based operation only 5 bits are used for such frames.
  */
 
 #include <speex/speex.h>