[FFmpeg-devel] [PATCH] avfilter: add compensationdelay filter

Ganesh Ajjanagadde gajjanag at mit.edu
Wed Nov 25 16:36:51 CET 2015


On Wed, Nov 25, 2015 at 9:50 AM, Moritz Barsnick <barsnick at gmx.net> wrote:
> On Wed, Nov 25, 2015 at 09:48:36 +0100, Paul B Mahol wrote:
>> Patch attached.
>
>> +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 you will get 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.
>
>   For example, you have recorded a guitar with two microphones placed
>   in different locations.
>
> This part I don't actually understand (is the fixed speed really the
> reason?), but I fixed the grammar anyway:
>
>   Because the front of sound wave travels at 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 a difference of ~30 cm in the
>   distances between source and microphones leads to one microphone
>   capturing its signal in antiphase to the other.
>
>   That makes the final mix sound moody. This filter helps to solve
>   phasing problems by adding different delays to each microphone track
>   and make them synchronized.
>
> I'm not sure "synchronized" is the correct term though, but I'm no
> expert.

Synchronized should be fine, for a more technical audience who desire
precise terms, above paragraph has a "in phase (synchronized)"
clarifying the colloquialism.

BTW, last line could be better as "and thus making them synchronized".

[...]


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