Real-time audio over local network with good quality

Real-time audio over local network with good quality

[Ricardo Biehl]

Hello guys!

Sorry if this question is not part of the scope of this list.

I'm developing a real-time microphone system that will work over local
network using ALSA library and sockets API with IP (UDP/TCP support)
<https://github.com/ricardobiehl/ipmic>.
The purpose is to make a good replacement to traditional microphone
systems (wired or wireless).
The problem is that I found difficulties in network control and in
ALSA library too :-) .
Basically I need help to select the best network scheduler algorithm,
set the right parameters, and (in audio) create a PCM plug which
supports (1 channel * 16 bit sample * 22050 Hz) and BLOCKING opening
mode. All this without quality loss and real-time.

Any contribution with the project is welcome!

Thank you!

-- 
Ricardo Biehl Pasquali

Real-time audio over local network with good quality

[Henrik Austad]

On Sun, Mar 27, 2016 at 9:18 PM, Ricardo Biehl <rbpoficial@gmail.com> wrote:
> Hello guys!

Hi Ricardo,

> Sorry if this question is not part of the scope of this list.
>
> I'm developing a real-time microphone system that will work over local
> network using ALSA library and sockets API with IP (UDP/TCP support)
> <https://github.com/ricardobiehl/ipmic>.

This looks like pure userspace, and going up to the level above, this
list is probably not the best place for it.

> The purpose is to make a good replacement to traditional microphone
> systems (wired or wireless).
> The problem is that I found difficulties in network control and in
> ALSA library too :-) .

Yes, I know :)

> Basically I need help to select the best network scheduler algorithm,
> set the right parameters, and (in audio) create a PCM plug which
> supports (1 channel * 16 bit sample * 22050 Hz) and BLOCKING opening
> mode. All this without quality loss and real-time.

Theres a lot of details you gloss over here, that will eventually have
to be solved

1) how do you handle signalling (mic goes way, new one appears)
2) what kind of equipment do you support? (one computer for each mic
gives you expensive mics)
3) signal (time)correlation, you need some timestamping to the samples
to if you are going to combine local feedback
4) Consistent alsa config across all endpoints

What you need is network hardware, both in the NIC and in the network
infrastructure that can properly prioritize your streams and provide
accurate timestamps.

Have you looked at similar projects, like AES67 and TSN/AVB?

AES67 is a best-effort approach, TSN requires support in the network
to prioritize the streams. Go and have a gander at OpenAVB  [1]

> Any contribution with the project is welcome!

There may be something in the works that will be shipped out for RFC
soon (see [2])


1) https://github.com/AVnu/Open-AVB
2) http://mailman.alsa-project.org/pipermail/alsa-devel/2014-May/077087.html

-- 
Henrik Austad

Real-time audio over local network with good quality

[Ricardo Biehl]

2016-03-27 23:27 GMT-03:00 Rohit Vashist <rohitvashist2kk3@gmail.com>:
> Hello Ricardo,
>
> Hope you are good.
> I would suggest you post the query on alsa dev list(mail forum) for more
> specific reply on your queries on ALSA driver.

Ok, thanks :-)
I'll do it!

> Also,i kind of like the idea.Are you looking for some assistance on your
> project would love to contribute.

Cool!
As I've told, anyone is welcomed to contribute in the project,
provided that it respects the original purpose and the KISS philosophy.

>
> I am working in an MNC in Audio Driver Domain for last 7 years.

Wow!

>
> https://www.linkedin.com/profile/preview?locale=en_US&trk=prof-0-sb-preview-primary-button

^ this link didn't open :-(

Cheers and thank you for reply!

>
> On Mon, Mar 28, 2016 at 12:48 AM, Ricardo Biehl <rbpoficial@gmail.com>
> wrote:
>>
>> Hello guys!
>>
>> Sorry if this question is not part of the scope of this list.
>>
>> I'm developing a real-time microphone system that will work over local
>> network using ALSA library and sockets API with IP (UDP/TCP support)
>> <https://github.com/ricardobiehl/ipmic>.
>> The purpose is to make a good replacement to traditional microphone
>> systems (wired or wireless).
>> The problem is that I found difficulties in network control and in
>> ALSA library too :-) .
>> Basically I need help to select the best network scheduler algorithm,
>> set the right parameters, and (in audio) create a PCM plug which
>> supports (1 channel * 16 bit sample * 22050 Hz) and BLOCKING opening
>> mode. All this without quality loss and real-time.
>>
>> Any contribution with the project is welcome!
>>
>> Thank you!
>>
>> --
>> Ricardo Biehl Pasquali
>>
>> _______________________________________________
>> Kernelnewbies mailing list
>> Kernelnewbies at kernelnewbies.org
>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>
>
>
> --
> Regards,
> Rohit Vashist
>
>

-- 
Ricardo Biehl Pasquali

2016-03-27 23:27 GMT-03:00 Rohit Vashist <rohitvashist2kk3@gmail.com>:
> Hello Ricardo,
>
> Hope you are good.
> I would suggest you post the query on alsa dev list(mail forum) for more
> specific reply on your queries on ALSA driver.
> Also,i kind of like the idea.Are you looking for some assistance on your
> project would love to contribute.
>
> I am working in an MNC in Audio Driver Domain for last 7 years.
>
> https://www.linkedin.com/profile/preview?locale=en_US&trk=prof-0-sb-preview-primary-button
>
> On Mon, Mar 28, 2016 at 12:48 AM, Ricardo Biehl <rbpoficial@gmail.com>
> wrote:
>>
>> Hello guys!
>>
>> Sorry if this question is not part of the scope of this list.
>>
>> I'm developing a real-time microphone system that will work over local
>> network using ALSA library and sockets API with IP (UDP/TCP support)
>> <https://github.com/ricardobiehl/ipmic>.
>> The purpose is to make a good replacement to traditional microphone
>> systems (wired or wireless).
>> The problem is that I found difficulties in network control and in
>> ALSA library too :-) .
>> Basically I need help to select the best network scheduler algorithm,
>> set the right parameters, and (in audio) create a PCM plug which
>> supports (1 channel * 16 bit sample * 22050 Hz) and BLOCKING opening
>> mode. All this without quality loss and real-time.
>>
>> Any contribution with the project is welcome!
>>
>> Thank you!
>>
>> --
>> Ricardo Biehl Pasquali
>>
>> _______________________________________________
>> Kernelnewbies mailing list
>> Kernelnewbies at kernelnewbies.org
>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>
>
>
> --
> Regards,
> Rohit Vashist
>
>



-- 
Ricardo Biehl Pasquali

Real-time audio over local network with good quality

[Ricardo Biehl]

2016-03-28 4:42 GMT-03:00 Henrik Austad <henrik@austad.us>:
> On Sun, Mar 27, 2016 at 9:18 PM, Ricardo Biehl <rbpoficial@gmail.com> wrote:
>> Hello guys!
>
> Hi Ricardo,
>
>> Sorry if this question is not part of the scope of this list.
>>
>> I'm developing a real-time microphone system that will work over local
>> network using ALSA library and sockets API with IP (UDP/TCP support)
>> <https://github.com/ricardobiehl/ipmic>.
>
> This looks like pure userspace, and going up to the level above, this
> list is probably not the best place for it.

Thank you, I'll avoid to write messages like this.

>
>> The purpose is to make a good replacement to traditional microphone
>> systems (wired or wireless).
>> The problem is that I found difficulties in network control and in
>> ALSA library too :-) .
>
> Yes, I know :)

:-)

>
>> Basically I need help to select the best network scheduler algorithm,
>> set the right parameters, and (in audio) create a PCM plug which
>> supports (1 channel * 16 bit sample * 22050 Hz) and BLOCKING opening
>> mode. All this without quality loss and real-time.
>
> Theres a lot of details you gloss over here, that will eventually have
> to be solved
>
> 1) how do you handle signalling (mic goes way, new one appears)
> 2) what kind of equipment do you support? (one computer for each mic
> gives you expensive mics)
> 3) signal (time)correlation, you need some timestamping to the samples
> to if you are going to combine local feedback
> 4) Consistent alsa config across all endpoints

These factors are really important, I'm going to thinking about!

1 -> In my current state I do not have signal handling yet.
1 -> Equipment is a detail which I'm very concerned, I thought
smartphones is a good transmitter. :-) .
3 -> I think timestamping could be ignored right now in my current branch!?
4 -> ALSA conf files are one of the most important parts, because they
are necessary to convert rate etc.

>
> What you need is network hardware, both in the NIC and in the network
> infrastructure that can properly prioritize your streams and provide
> accurate timestamps.

It's ok.

>
> Have you looked at similar projects, like AES67 and TSN/AVB?
>
> AES67 is a best-effort approach, TSN requires support in the network
> to prioritize the streams. Go and have a gander at OpenAVB  [1]
>
>> Any contribution with the project is welcome!
>
> There may be something in the works that will be shipped out for RFC
> soon (see [2])
>

I haven't looked it yet, thanks!

Thank you for reply!
Big hug!

>
> 1) https://github.com/AVnu/Open-AVB
> 2) http://mailman.alsa-project.org/pipermail/alsa-devel/2014-May/077087.html
>
> --
> Henrik Austad



-- 
Ricardo Biehl Pasquali