still confused about latency

[jim nualart]

Hello all,

I've read and re-read this section several times and am embarrassed to admit that I'm still somewhat confused.

https://gstreamer.freedesktop.org/documentation/additional/design/latency.html?gi-language=python#query

I have a pipeline that I queried the latency on and I do see it change as I add/remove sources. Conceptually this makes sense to me. No problem there. But the min & max values that are returned do not. I get a min of 160ms and a max of 100ms.

I'm having trouble reconciling those numbers with the description in the above link.

Based on the documentation, I interpret this as "my pipeline has a maximum latency of 160ms" AND "my pipeline can buffer 100ms of data before blocking/dropping data". I feel like maybe I'm missing something here.

Can anyone set me straight here? I should add that my pipeline works as expected (mostly -- it does have some small issues, but nothing close to dropping data).

thanks in advance,

-jaime

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[Nicolas Dufresne-5]

Le dim. 12 juill. 2020 06 h 45, jim nualart <[hidden email]> a écrit :

Hello all,

I've read and re-read this section several times and am embarrassed to admit that I'm still somewhat confused.

https://gstreamer.freedesktop.org/documentation/additional/design/latency.html?gi-language=python#query

I have a pipeline that I queried the latency on and I do see it change as I add/remove sources. Conceptually this makes sense to me. No problem there. But the min & max values that are returned do not. I get a min of 160ms and a max of 100ms.

The pipeline should also warn in the condition. This means you don't have enough buffering to delay your playback to ensure all streams are on sync. Add queues were needed.

I'm having trouble reconciling those numbers with the description in the above link.

Based on the documentation, I interpret this as "my pipeline has a maximum latency of 160ms" AND "my pipeline can buffer 100ms of data before blocking/dropping data". I feel like maybe I'm missing something here.

Can anyone set me straight here? I should add that my pipeline works as expected (mostly -- it does have some small issues, but nothing close to dropping data).

thanks in advance,

-jaime

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[jim nualart]

------------------------------

Message: 2
Date: Sun, 12 Jul 2020 09:19:38 -0400
From: Nicolas Dufresne <[hidden email]>
To: Discussion of the development of and with GStreamer
        <[hidden email]>
Subject: Re: still confused about latency
Message-ID:
        <[hidden email]>
Content-Type: text/plain; charset="utf-8"

Le dim. 12 juill. 2020 06 h 45, jim nualart <[hidden email]> a ?crit :

> Hello all,
>
> I've read and re-read this section several times and am embarrassed to
> admit that I'm still somewhat confused.
>
>
> https://gstreamer.freedesktop.org/documentation/additional/design/latency.html?gi-language=python#query
>
> I have a pipeline that I queried the latency on and I do see it change as
> I add/remove sources. Conceptually this makes sense to me. No problem
> there. But the min & max values that are returned do not. I get a min of
> 160ms and a max of 100ms.
>

The pipeline should also warn in the condition. This means you don't have
enough buffering to delay your playback to ensure all streams are on sync.
Add queues were needed.

In my pipeline, I have several inputs going to an audiomixer, then a tee, then several outputs. All outputs attach to the tee using their own queue (default properties, except for being set to "leaky downstream") elements and graphs show me that the queues are not anywhere near to leaking. This is part of the reason why the max 100ms value confuses me. Does placing queues at the end of each input where they connect to the audiomixer make sense?

 

> I'm having trouble reconciling those numbers with the description in the
> above link.
>
> Based on the documentation, I interpret this as "my pipeline has a maximum
> latency of 160ms" AND "my pipeline can buffer 100ms of data before
> blocking/dropping data". I feel like maybe I'm missing something here.
>
> Can anyone set me straight here? I should add that my pipeline works as
> expected (mostly -- it does have some small issues, but nothing close to
> dropping data).
>
> thanks in advance,
> -jaime
> _______________________________________________
> gstreamer-devel mailing list
> [hidden email]
> https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
>
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