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Upsampling ODF from 44.1KHz to 48KHz

Sampling pipe organs and turning them into something you can play in Hauptwerk.
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elia

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Upsampling ODF from 44.1KHz to 48KHz

PostSun Oct 21, 2012 12:20 pm

Removed



This is obviously a simple compromise in order to integrate other VSTi / AUi at a fixed frequency of 48KHz. Fortunately, many pipe organs have a frequency of 48 kHz with a few exceptions such as "1966 Casavant Freres". In the latter case just change a number (from 2 (= 44.1) to 3 (= 48) in unencrypted ODF _General entity, AudioOut_OptimalFormat_SampleRateCode setting) to obtain the result without sacrificing fidelity and without to buy expensive realtime SRC (Sample Rate Converter) hardware to process multichannel audio.

It seems to me a good result (?).

Thanks

Elia
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Re: Upsampling ODF from 44.1KHz to 48KHz

PostSun Oct 21, 2012 7:48 pm

Hello Elia,

Please remember the sample set creation guide is a confidential document and not to be posted publicly anywhere or sent to anyone, when we sent this out you would have agreed to this prior to downloading. I have removed that portion of text due to this.

As long as the sound output sounds OK to you then editing that option in the ODF is fine, just be aware that if there is any aliasing distortion then this would most likely be the reason for it.
Brett Milan
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MILAN DIGITAL AUDIO
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elia

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Re: Upsampling ODF from 44.1KHz to 48KHz

PostMon Oct 22, 2012 1:32 pm

I'm sorry Brett, next time I will make a very superficial summary (if necessary) of the original content to be more clear with your readers. I have not forgotten the license and I have mentioned only the information about secondary aspects of Hauptwerk. In fact Hauptwerk can help you reach the goal, however, it is possible to use other tools (hardware or software). I hope that you will appreciate the good intentions.

In any case, to avoid making unnecessary words I wanted to consider only the resampling in real time and it is certainly an advantage to do so with Hauptwerk (only ODF unencrypted and upsampling).

Of course, the implementations ( and fidelity ) are many and the main purpose is the integration of heterogeneous elements.

To be more explicit, I wanted to know if it is available a software solution for higher scalability at a lower cost.

It seems that the market leader in this sector is iZotope 64-bit SRC but it is not available as a realtime plugin. Only for the offline process...


The hardware solutions are more complicated to apply and less flexible. Generally synchronisation may be achieved via Wordclock or AES3id (AES11). For example, I use Echo Audiofire12 with two Lynx AES16e-SRC cards but it is quite uncomfortable.


Best regards
Elia



Behringer UltraMatch PRO SRC2496
http://www.behringer.com/EN/Products/SRC2496.aspx
2-Channel Sample Rate Conversion

RME ADI-192
http://www.rme-audio.de/en_products_adi_192_dd.php
8-Channel Sample Rate Conversion

Lynx Studio Technology AES16e-SRC PCI Express AES/EBU Interfaces
http://www.lynxstudio.com/product_detail.asp?i=16
16-Channel Sample Rate Conversion

D.O.TEC® MADI.SRC
http://www.directout.eu/en/support/down ... i.src.html
64-Channel Sample Rate Conversion
Elia
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Re: Upsampling ODF from 44.1KHz to 48KHz

PostTue Mar 26, 2013 7:56 am

For completeness, there is an open-source software solution scalable, flexible and high quality on the jack audio infrastructure :

Linux Audio Conference 2012 : Controlling adaptive resampling
http://kokkinizita.linuxaudio.org/paper ... resamp.pdf

Libzita-resampler library designed to be used within a real-time processing context, to be fast, and to provide high-quality sample rate conversion
http://kokkinizita.linuxaudio.org/linux ... mpler.html

ALSA / JACK bridge applications
http://kokkinizita.linuxaudio.org/linux ... guide.html
.

The prerequisites are the jack audio infrastructure (netjack to be more precise) on a real time linux audio distribution (http://ubuntustudio.org/).

Basically it has maintaining the flow of conversion of two or more jack unsynchronized domains instances on the same machine that acts as a hardware real-tiime SRC between different jack audio domains :

audio_input(44.1KHz) -> |jackd1(44.1KHz)| --> |adaptive_resampling| ---> |jackd2(48KHz)| -> audio_output(48KHz)

.

Many details (not really easy to manage) are provided in the documents mentioned above.
Elia

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