[Icecast-dev] Radio Loudness

[Roman Gorshunov]

Dear Patrick,

> We saw that the following commands are coming from the Backend IceCast
Proxy to the Android STB
Icecast does not explicitly send any commands to its clients (players). It
simply pushes audio streams and a little bit of metadata (title, artist,
bitrate, etc.) over HTTP.

HTTP protocol and Icecast do allow embedding arbitrary HTTP protocol
headers [0] and send them to the client, and it would be up to the client
to interpret them. However, these headers are rather static, and can not be
changed dynamically on the fly. If your media sources require different but
static adjustment of loudness (e.g. "Radio 1" always needs "+10"
adjustment, and "radio 2" always nesds "-5" adjustment), then you can set
it in your custom HTTP headers per mount point, and process those settings
in your client (ExoPlayer in STB?) to change volume. With a bit of software
development you could make it possible to adjust HTTP headers dynamically
[1]. To do so you would need to continuously monitor loudness of source
media streams and send metadata update commands to the Icecast server.

Another possible solution would be to add a software between your original
media sources (radio stations) and Icecast, which will normalize loudness
and then push modified audio to Icecast as a media source. Some possible
media source clients are listed [2] on Icecast web site.

[0] - https://icecast.org/docs/icecast-2.4.1/config-file.html#mountsettings
, look for <http-headers> description
[1] - in a way similar to stream Metadata updates
https://icecast.org/docs/icecast-2.4.1/admin-interface.html
[2] - https://icecast.org/apps/

Best regards,
Roman Gorshunov

On Thu, 25 Aug 2022 at 12:48, <Patrick.Schneider1 at swisscom.com> wrote:

> Dear Roman
>
> Thank you for your answer.
>
> We as Swisscom Switzerland are in a difficult situation. We have around
> 1'000 Live / Replay TV Channels and 500 Radio Channels on our Platform.
> For Live TV we could manage the Loudness in the Transcoder/Encoding
> Settings. We were able to measure and align all Loudness differences and
> adjust to -23dB.
> Zapping from one TV Channel to another makes no audible difference anymore.
>
> The Problem is the change from Live TV to Radio on our Android Set-Top-Box.
> We are looking for a solution to align the Radio Loudness over the 500
> Radio Channels.
>
> So you don't see any possibility to send an ExoPlayer message (like a
> Metadata) to the Player?
>
> We saw that the following commands are coming from the Backend IceCast
> Proxy to the Android STB:
>
>
>
> tvlib.ExoRadioPlayer: onPlaybackStateChanged(state=Idle)
>
> tvlib.ExoRadioPlayer: onIsLoadingChanged(isLoading=false)
>
> tvlib.ExoRadioPlayer: onPlaybackStateChanged(state=Buffering)
>
> Why not adding a ExoPlayer Volume Parameter within the Radio Channel start
> For example …
> exoPlayer.sendMessage(audioRenderer,
> MediaCodecAudioTrackRenderer.MSG_SET_VOLUME, 0.9f);
>
>
> A static setting on the ExoPlayer in the client is not an option, because
> the Player is also used by other applications.
> Changing Volume in Set-top-box will affect all applications.
>
> Sincerely,
> Patrick
>
>
>
> *Von:* Roman Gorshunov <paye600 at gmail.com>
> *Gesendet:* Mittwoch, 24. August 2022 19:18
> *An:* Schneider Patrick, B2C-TSP-ITE <Patrick.Schneider1 at swisscom.com>
> *Cc:* icecast-dev at xiph.org
> *Betreff:* Re: [Icecast-dev] Radio Loudness
>
>
>
> Hello Patrick,
>
>
>
> It’s not really a media streaming server’s (Icecast) job to alter the
> volume. Volume is set either by the media source or in player.
>
> In addition to that, media streaming server does not allow clients
> (players) to control media source (e.g. change volume or skip tracks).
>
>
>
> I might misunderstood your question though.
>
>
>
> Best regards,
>
> Roman Gorshunov
>
>
>
> On 24 Aug 2022, at 11:11, Patrick.Schneider1 at swisscom.com wrote:
>
> 
>
> Dear All
>
> We are looking for a solution to send a volume parameter to our ExoPlayer
> during the icecast streaming initialization phase.
> Something like this …
>
> Volume example:
>         exoPlayer.sendMessage(audioRenderer,
> MediaCodecAudioTrackRenderer.MSG_SET_VOLUME, 0.9f);
>
>
> Is there a way to set the icecast egress streaming with an ExoPlayer
> default Volume?
>
> Sincerely,
> Patrick
>
>
>
>
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>
>
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