[LAU] Need to create delay or artificial latency

[Robin Gareus]

On 04/04/2011 08:17 AM, Arnold Krille wrote:
> On Monday 04 April 2011 07:55:02 Patrick Shirkey wrote:
>> So puredata can't buffer 4 hours of data? Is that a limitation of  the
>> available memory or the internal format or what? Ardour can records for
>> at least 10 hours non stop.
> 
> Ardour records to disk, puredata's delay buffers in memory.
> 
>> Maybe ecasound is a better tool for this procedure?
> 
> A "delay" of four hours can only be implemented involving the harddisk. Unless 
> you have an incredible amount of ram.

48000 SPS * 4bytes/sample * 3600sec/h * 4h
= 2764800000 ~ 2.5 GBytes  (per channel)

on 32bit machines you'll run out of address space even with enough RAM.

> I think a homebrewn solution is to use here. And that is my idea:
> One app/script to record to disk and start a new file every hour with the 
> timestamp in the filename for debugging.
> Another app to play the files at the wanted time.
>
> That way any delay bigger then the interval of the first apps files can be 
> created.

If you want _exactly_ 4 hours (and not 4 hours + 1 ms) it's easier to
count samples and compensate latency in the same app.

2c,
robin