[LAU] Audio seamless switch

[Ralf Mardorf]

On Sun, 2018-06-17 at 08:16 +0000, Benny Alexandar wrote:
> >>>why would you need to resample/stretch them? 
> As mentioned earlier the two audio are identical but one will be ahead/delayed than other. 
> The user who is listening to it should not notice the switching, and this 
> switching happens when the quality of one audio is degraded compared to other. 

Hi Ben,

"ahead/delayed" could be caused by different sync issues. And
"identically" as well as "degraded" could be interpreted in different
ways.

You mentioned "one audio receiving from network and other thru air".

For example a single CD player's audio signal is send wireless to an
audio interface and by a network cable the same audio output of this CD
player is send to a network interface, you are not using two CD players
playing the same CD.

I don't have knowledge about wireless audio and audio by network, but I
suspect that it's similar to using two sound cards. To avoid "degraded"
sound quality two sound cards needs to be synced by a single clock
source e.g. word clock or you need to workaround this sync issue by
using software such as zita-ajbridge. That's one kind of sync issue.

Another kind of sync issue could be caused by e.g. distance. For
example, one audio cable is 10 meters short, the other is as long as
from Earth to Mars and back. To workaround this time difference you
could use a delay effect, to delay the signal provided by the short
cable.

Assuming two CD player's should play the same CD, or better let's assume
two different professional audio recorders are individually playing the
same recording, instead of just using the signal of a single
professional audio recorder, you need to sync the two machines by a
timecode, such as SMPTE, to avoid drift.

You should be more detailed about the issue. What is the source of the
audio signal/s? What is "wireless" for? In what way is the audio quality
"degraded"? Is always the same sample rate etc. used? What software are
you using for mixing/switching the signals?

Regards,
Ralf