[Icecast] Higher quality narrowband streaming options

TheDarkener thedarkener at logicalnetworking.net
Wed Aug 1 21:04:05 UTC 2012

If you do further testing with Opus, please let us know your findings.
I'm interested in this newer codec myself. I'm currently using vorbis
for my radio station (similar to yours, a no-budget Internet station)
and support for it is limited (nothing on iOS that I know of, and
Android (AFAIK with my very old Android phone) doesn't support it OOTB
(but XIAA Live Lite handles vorbis streaming wonderfully). I've looked
into having a generic (but customizable) Android/iOS radio player
developed that centers on open codecs such as Vorbis/Speex/Opus. Who's
willing to chip in with me to get it done? :) Would be really cool to
have a definitive player that we could refer people to.

- Jordan

On 08/01/2012 01:50 PM, Geoff Shang wrote:
> Hi,
> Up until now, I've been providing narrowband streams at 24kbps MP3.  We've 
> reluctantly been using MP3 instead of say Ogg Vorbis due to wider 
> support.
> But it's getting to the point where low bitrate MP3 doesn't really cut it 
> anymore.  With technologies like AACPlus out there in common usage, people 
> have come to expect better and one can hardly blame them.
>   So I thought I'd start a thread on low bitrate streaming in order to find 
> out what people are using and how.
> There seem to be two issues.  The first is which format to use and the 
> second is how to go about transcoding into said format.
> Right now we're using StreamTranscoderv3 to do our transcoding.  It can 
> turn around our broadband stream as a narrowband stream without any 
> intervention.  I've successfully used it to turn around streams as MP3 and 
> Ogg Vorbis.  It's also meant to support AAC and AACPlus, but I've not 
> managed to figure out how to enable this under Linux or how I would 
> particularly get it to be able to do AACPlus.
> I considered going so far as to try Nullsoft's sc_trans v2 to encode 
> AACPlus, but it seems it cannot connect to an existing stream and relay 
> it, it can only have a stream connect to it.  I don't see how I can get 
> our existing Icecast stream to be relayed to sc_trans as Icecast does not 
> do push relaying, so this option would appear to be out.
> I also took a brief look at Liquid Soap for doing this.  It would appear 
> that it can, but it looks like a lot of work to deploy for a relatively 
> simple task.  Still, I'd consider it if it will do the job.
> This of course leads to the broader question of which format to use.  For 
> us, the chief concern is device support.  While a lot of people get around 
> this issue by writing their own apps with built-in decoders, this isn't a 
> direction I'd particularly want to go in unless there's something out 
> there that's fairly generic and can be easily customisable.  Our station 
> is a volunteer outfit with no budget, so my strong preference would be for 
> us to use a natively supported format so that it "just works".
> As mentioned, I'm looking to depricate MP3.   It's really not possible to 
> get 44.1 kHz MP3 under 56 kbps, and that only in mono.  This isn't really 
> "narrow" enough for my tastes.
> I'm not a big expert on AAC, but it seems to me that plain AAC (no 
> "plus") doesn't really offer much over and above MP3.   Certainly, samples 
> I've heard of 56 kbps AAC streams at 44.1 kHz stereo are rolled off to 5 
> kHz audio, making it sound worse than MP3 at the same rate using 22.05 kHz 
> samples.   But there's so many AAC parameters that I'm by no means an 
> expert on this.
> From the little I've seen, the favoured option for lower bitrate streaming 
> seems to be AACPlus.  And it's not surprising given how good it sounds. 
> I'm not so sure about device support though, and encoding it is a bit of 
> an issue (see above).  There is libaacplus, but streamTranscoderv3 doesn't 
> *appear* to support it.  I think Liquid Soap might though.  There's also 
> something called AACPlusEnc but I can't seem to get to its home page.
> While we're considering non-free options, Windows Media Audio would seem 
> to be out due to the desire to encode under Linux, and people seem to be 
> moving away from Real Audio.
> Of course, I'd prefer to use something open if people can actually listen 
> to it.  There would appear to be the following options:
> Ogg Vorbis: Using oggenc with libvorbis 20100325 (1.3.1) at quality -1 
> with a  44.1 kHz mono source, I can get the bit rate down to about 34 
> kbps.  Stereo is more like 40 kbps.  It actually sounds pretty good. 
> Maybe if I took it down to 32 kHz 
> it would go a little ower, or perhaps the quality -2 mode that at least 
> was available in the aoTuV encoder would get it lower with perhaps a 
> little more quality loss.  I've not actually tried lower bitrate stuff in 
> either vorbis encoder for some time.
> Encoding Ogg Vorbis won't present any problems.  My concern about Ogg 
> Vorbis is support in mobile devices.  I know that iOS devices don't 
> support it natively.  Do any stream players for iOS support it, like say 
> Tunein Radio?  I believe Android devices do.  Don't know about other 
> devices used on the go.
> The other open option I can think of is Opus.  I've not put it through its 
> paces, I really should.  But it aims at least to be good for this sort of 
> thing.  But I'm really not at all sure what software support is like yet, 
> either for encoding or listening.  Anyone know?
> Are there any other options that are worth looking at?
> Geoff.
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Jordan (PGP: 0xDA470FF8)

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