From 66a4ac5182777ef0ade673c89a4766909ac9d00c Mon Sep 17 00:00:00 2001 From: Dmitry Samonenko Date: Fri, 5 Oct 2012 00:42:31 +0400 Subject: [PATCH] libspeexenc: Updated commentary to reflect recent changes Signed-off-by: Michael Niedermayer --- libavcodec/libspeexenc.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/libavcodec/libspeexenc.c b/libavcodec/libspeexenc.c index 97a2ea5285..e3db143f75 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