H Alan & others,
I have some experience with distribution of AV over IP.
Various encoding algorithms produce some delay between picture and audio
even over short distances.
Most of the play code has some vernier adjustment to sync the words and
picture.
Some encoding allows a FEC adjustment.
Inevitably there is some buffering so 'live' DTV is actually a bit
behind the origination. More so than it was in analogue.
Playout with some dedicated program like VLC is often better then
Firefox or Chrome or Safari [or ..]
Problems can start with the source. So a camera limitation can control
the whole chain.
Pick the software : [ big blue ]
Run it up on the best hardware you can find.
Use the best possible cameras for the head end.
That said you can get some amazing video from cameras that don't cost
huge amounts.
Browser implementation of DTV is a challenge as there are an incredible
number of standards.
I am currently monitoring an on line feed of a FTA TV channel where the
live presenter audio is out of sync but the video clips are in sync.
I suspect the TS from the live studio is at a higher resolution needing
more time to process.
Digital has a lot of advantages but it comes with a lot of things that
have to be allowed for.
regards
Robert
On 26/04/21 11:26 pm, alant123@xxxxxxxxxxxxx wrote:
Well, as has been said - this is very little to do with Sox. However, let
me chip in an observation.
Having a mostly finished video library that uses HTML5 pages to browse and
play I can testify that the video player infrastructure quality between
browsers no Windows varies a LOT and one of the issues with viewing streams
on a LAN is audio sync (that and random stops). Strangely, because I had
never used it for anything ever before, I have found that the Microsoft Edge
browser is the only one that is rock solid for media playing in this way.
So, since your application is also LAN based video streaming I wondered if
you had tried Edge or not?
I had problems with Firefox player (frequent and various issues including
sync), Chrome (less frequent but usually sync or random stops) and also IE
(all kinds of problems) - but Edge plays my video library content (which
varies from 1mbit/sec up to 15Mb/second almost all H264 in MP4 containers)
from my LAN based Apache server (also on Windows) reliably and with no
issues.
Just a thought.
Alan T
-----Original Message-----
From: Jan Stary <hans@xxxxxxxx>
Sent: 26 April 2021 11:48
To: sox-users@xxxxxxxxxxxxxxxxxxxxx
Subject: Re: windows 10 setting up SoX for live-streaming
Mikrophone-->---LAN--------Soundcard realtime audio-transmission
On Apr 25 19:06:45, sox-users@xxxxxxxxxxxxxxxxxxxxx wrote:
Ah ! I forgot to write about the real situation: *live*-streaming
across the local network.
I'm working as a teacher and have to teach a class that is separated
into two halfs each half in its own room to limit the number of
persons per room.
I'm forced to use Big Blue Button as the video-conference solution.
Well, you already have your tool to do it then.
Though the bandwidth of the internetconnection and/or the
server-"bandwidth"
to process the video-sreaming-data
for a lot of conferences at the same time. Is limited which causes
lagging of the audio.
I find it strange that a video conferencing software would not keep sync
(not that it lags _as_a_whole_, that's understandable). Do you meen to say
that tha audio lags out of sync of how much the video lags?
Under this circumstances (small bandwidth/overloaded server) Big
Blue Button is more like a Little-Black-Hole that disrupts the data
into nowhere-nexus ;-)
So I'm searching for an alternative for "*live*-streaming the audio.
That might make the audio even more out of sync with the audio.
If the rooms are next to each other an oldfashioned analog microphone
connected to an oldfashioned analog amplifyer with a 50m long
speaker-cable has 0 Milliseconds latency and is "rock-stable" as a
neutron-star
Do youself a favour and install two unix machines; this becomes a non-issue.
At any rate, this doesn't have much to do with sox.
Jan
Am 25.04.2021 um 16:51 schrieb Jan Stary:
On Apr 25 15:54:13, dipl-ing.ludwig@xxxxxxxxxxx wrote:
Am 24.04.2021 um 20:31 schrieb Jan Stary:
On Apr 22 21:13:48, sox-users@xxxxxxxxxxxxxxxxxxxxx wrote:
I would like to use SoX for this scenario me speaking
-----> inbuild micrphone of my tablet (Windows 10)
---------->----------LAN------->---------second
PC----->------soundcard---->----Amplifier------>Speaker
PC----->------soundcard---->----Amplifier------>----> my
PC----->------soundcard---->----Amplifier------>words as
*realtime* audio
I don't think this is a sox problem: any other audio
application will have to fit into that scenario similarly.
If I understand right I have to setup IP-adresses and ports.
Well, obviously, if you want to send data over LAN.
This has nothing to do with SoX.
Is there somewhere a collection of batch-files or a
parameterlists that show which parameters and options I have
to use for this?
No.
I you just want to send the audio unchanged to another
machine, SoX might not even be the tool for you: you just
need one machine to record, and send the data to the other
machine (as you would send any other data), and have the other
machine play it back.
It this wasn't windows, I would put a one-liner here that
does exactly that.
Jan
I have found this website
https://www.streamingmediaglobal.com/Articles/Editorial/Featur
ed-Articles/DIY-Rudimentary-Audio-Streaming-124222.aspx?utm_so
urce=dlvr.it&utm_medium=feed&utm_campaign=iti%20roundup
Which shows how to do it with SoX. But it seems a description
for how to do it on Linux-machines
Surprise: rec | nc
rec reads from a device and writes to stdout; netcat reads from
stdin and writes to a socket; the opposite happens on the other
end: nc | play.
On systems that have standard tools for fundamental things (such
as: read your input and send it down a network socket) this is
indeed a one-liner. But you are on windows; maybe windows also
has a netcat, I don't know.
Also note that this is not specific to SoX:
it could be arec/aplay with ALSA, or aucat/aucat on OpenBSD, or
any other program capable of recording/playback.
Jan
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--
Robert Jeffares
Communication Consultants
64 Warner Park Avenue
Laingholm
Auckland
New Zealand 0604
+64 9 817 6358
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