avfilter: add compensation delay line filter

Signed-off-by: Paul B Mahol <onemda@gmail.com>

1 files changed, 48 insertions, 0 deletions

diff --git a/doc/filters.texi b/doc/filters.texi
index a7f8a53f36..1d03cee0e3 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -1628,6 +1628,54 @@ compand=.1|.1:.1|.1:-45.1/-45.1|-45/-900|0/-900:.01:45:-90:.1
 @end example
 @end itemize
 
+@section compensationdelay
+
+Compensation Delay Line is a metric based delay to compensate differing
+positions of microphones or speakers.
+
+For example, you have recorded guitar with two microphones placed in
+different location. Because the front of sound wave has fixed speed in
+normal conditions, the phasing of microphones can vary and depends on
+their location and interposition. The best sound mix can be achieved when
+these microphones are in phase (synchronized). Note that distance of
+~30 cm between microphones makes one microphone to capture signal in
+antiphase to another microphone. That makes the final mix sounding moody.
+This filter helps to solve phasing problems by adding different delays
+to each microphone track and make them synchronized.
+
+The best result can be reached when you take one track as base and
+synchronize other tracks one by one with it.
+Remember that synchronization/delay tolerance depends on sample rate, too.
+Higher sample rates will give more tolerance.
+
+It accepts the following parameters:
+
+@table @option
+@item mm
+Set millimeters distance. This is compensation distance for fine tuning.
+Default is 0.
+
+@item cm
+Set cm distance. This is compensation distance for tightening distance setup.
+Default is 0.
+
+@item m
+Set meters distance. This is compensation distance for hard distance setup.
+Default is 0.
+
+@item dry
+Set dry amount. Amount of unprocessed (dry) signal.
+Default is 0.
+
+@item wet
+Set wet amount. Amount of processed (wet) signal.
+Default is 1.
+
+@item temp
+Set temperature degree in Celsius. This is the temperature of the environment.
+Default is 20.
+@end table
+
 @section dcshift
 Apply a DC shift to the audio.