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Inge
Man-At-Arms


Joined: 04 May 2003
Location: Nieuw Lekkerland @ Holland
PostPosted: Mon May 19 2003 22:53    
Creating a modem-friendly audiostream
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Hi All,

I've got a question about a streaming dance program that I host on my server (www.juice.tk). Besides a 112 kbit/44khz/stereo stream for broadband users, we think that it would be nice to also offer a 56k6 or single-isdn (64kb/s) stream. I'm uncertain though about the exact specifications such a mp3 should get. Let's imagine that a 56k6 can download with 56 kbit/sec (ofcourse, not true, it's just to discover the algorithm to be used). What should the exact specs be of an mp3 that can be streamed by such a connection? For instance, if I make a 56kbit/sec, 44 khz, stereo mp3, would that correspond? In my humble idea, I would guess that a stereo 56kbit/s mp3 would be 112 kbit/s because of the two channels, but ofcourse I'm not certain.

Any help would be appreciated (as usual)!

Kind regards,
Inge


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em22
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Joined: 06 May 2003
Location: Manchester, England
PostPosted: Mon May 19 2003 23:57    
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I could be sounding real nieve here, I really dont cater for people below 128kb now days. The price of a broadband connection (even though 128k and 256k are no longer considered broadband) has dropped so much, there doesn't seem to be any reason why someone who is committed to using the internet for their musical interests would have basic dial up. Dial up these days I find, is used by complete beginners.

My experience comes from working in broaband fro BT.

AS far as the streaming info, for a 56kbps stream you would need a real steady and fast 56k connection. The best is to use a 43kbs/sec stream, and then the safest with the quality going too low would be the 32k/sec. You can juggle which varible you wish to sacrifce for the compression gains. Basically do the stream with 42kb/sec which different options and just choose the best suitable for the track concerned.

Hope that Helps!


em22
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Sunbuster
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Joined: 05 May 2003
Location: Finland
PostPosted: Tue May 20 2003 09:54    
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em22 wrote:
I could be sounding real nieve here, I really dont cater for people below 128kb now days. The price of a broadband connection (even though 128k and 256k are no longer considered broadband) has dropped so much, there doesn't seem to be any reason why someone who is committed to using the internet for their musical interests would have basic dial up. Dial up these days I find, is used by complete beginners.



I have to agree with em22 here (not on the beginners part), I just don't see the benefits from hosting for dialup users these days anymore (sorry Inge, I know you're a dedicated modem user, but still Wink) The prices for a 256K adsl line is so low these days, anyone who spends more than one hour on the net per day would benefit from having one directly.

As for the bitrates to use I don't know, don't have any experience with hosting streaming services
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Martin
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Joined: 05 May 2003
Location: Norway
PostPosted: Tue May 20 2003 10:21    
I`m not sure
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But I think the bitrate will show in winamp if you download a music stream - so what you could do is check out what MP3.com uses for their "lo-fi" streaming. I use a ISDN (64 Kb) line and have no trouble with the "lo-fi" streaming from mp3.com

- Martin
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D Vibe
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Joined: 04 May 2003
Location: Sweden
PostPosted: Tue May 20 2003 11:50    
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Have you guys never heard of "the smallest common denominator" (direct translation from swedish (minsta gemensamma nämnaren), so I'm not sure it's correct words I'm using there Smile), which means that a perfect homepage works on all, or at least on as many as possible, type of systems/browsers.

What I mean is that if you want as broad audience as possible, you should never just *think* that everyone has adsl, or that everyone understands your layout of your homepage. One of those things are for example using flash, and one other are not including a low bitrate stream for ppl with modem.

Now, off to Inge's question, I'm not exactly sure, but I *think* that 56kbit/stereo is made for 56kbit-connections, but as someone else said before, you should use like 48kbit, or maybe 32kbit instead, so you know everyone can get as fluent stream as possible. This is only meant for previewing the track, if they like it they will download the 128kbit-version.

I'll look up that thing about 56kbit/stereo.

/Daniel


http://www.dvibe.se
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Inge
Man-At-Arms


Joined: 04 May 2003
Location: Nieuw Lekkerland @ Holland
PostPosted: Tue May 20 2003 13:43    
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Thanks so far for your reactions!

EM22 & Sunbuster: trust me, I think before I act Wink You might consider the possibility that I have fairly good reasons to put such a stream online, despite the fact that it sounds just plain horrible and broadband is the regular connection nowadays. Like Plato was answered like "yeah, well, hey, okay, I know that I have no explanation for the fact that I know the lenght of this line through this circle, but most of us nowadays uses squares anyway"...Very Happy

C-Frog: if you could find any definite answer, please let me know.

Inge

ps: yes, and Socrates commited suicide later because people didn't understand him. But that was not my point, so no need to worry about the results of this question Smile


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D Vibe
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Joined: 04 May 2003
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PostPosted: Tue May 20 2003 14:17    
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I've checked it out, and if I understood it correct it's 56kbit/channel, that is, you need to do it mono. But a tip is that you use like 40kbit and then use joint stereo.
You've got a 56kbit yourself, so maybe you can try what the optimal solution is?


http://www.dvibe.se
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Inge
Man-At-Arms


Joined: 04 May 2003
Location: Nieuw Lekkerland @ Holland
PostPosted: Tue May 20 2003 18:36    
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C-frog: thank you!

But what is joint stereo? Simply the integration of both channels into one mono-file?

I'll check it next week to see if a 40 kbit/s version will work. I suppose 44 khz is possible then?

Weird thing actually that there's both a kbit as an stereo as a bitdepth parameter, since I assumed that the kbit/s is the result of the stereo and bitdepth parameters.

Inge


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D Vibe
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Joined: 04 May 2003
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PostPosted: Tue May 20 2003 20:11    
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I believe joint stereo is fake stereo, which means that most of the information are saved on one mono channel and then adding the stereo difference in another one, which will for example cause less steps in the stereo.

Well, not hundered percent sure how it works, either not hundered percent sure how much bytes it will save Smile


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em22
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Joined: 06 May 2003
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PostPosted: Wed May 21 2003 01:42    
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c-frog wrote:
What I mean is that if you want as broad audience as possible, you should never just *think* that everyone has adsl, or that everyone understands your layout of your homepage. One of those things are for example using flash, and one other are not including a low bitrate stream for ppl with modem.


Yes, we know this - but if it wasn't for webmasters and other people creating sites that require a faster connections, and that keep pushing the requirements for a more powerful pc, we would all still be using Internet Explorer 1, Windows 3.11 and still banging out tunes using FastTrackerII with a GUS.

I myself submit tunes to a site which converts the tracks to a low-fi stream, at 24kbps 22khz mono. Which sounds fairly usless and kills the actual atmosphere of the track - and then it they create a hi-fi version, 128kbps standard MP3 specs - where the full glory of the track is present.

It's like that old debate about "why do I need a new computer?", "because old ones are crap", "but I can do everything I want here" - but then they constantly question people on how to overcome thier choice not to upgrade. I'm not saying you're annoying there by the way, just in case Razz

Just do 128kbps clips that will drop into winamp and then those on lower speed conections can wait a few seconds before hearing the track. Otherwise I don't know. I must admit I'm stoned, and I think I have lost my train of thought somewhere.

Where we talking about trips? Confused

;p


em22
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mikx
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Joined: 05 May 2003
Location: Melbourne
PostPosted: Wed May 21 2003 06:20    
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hello !!

i'm on 56k and i'm no begginer to internet, just that broadband prices here in australia are so FUCKING high that i can't afford it.. (apologies for outburst Wink )

anyway, i've done some streaming in my time (i used to DJ for a fairly popular Austnet IRC channel, using live365, a shoutcast streaming server that allowed streams to be uploaded, and others could connect to it and download them, back when it was still free), and i found that the best stream is 24kbps, 22Khz Mono for pretty low-fi sound but without going extreme low (the music is still very audible). although i have never tried anything faster (because as you know, 56k modems send data at only 33.6kb/s at most), however, i do believe that you'll easily get away with sending a 40kbps, 22Khz Stereo stream and all 56k modem users should pick this up. if you want to go higher quality, 48kbps, 22kHz Stereo could be the way to go, but any higher (the next one up in shoutcast is 56kbps) and probably many modem users would get heaps of buffer underruns..

hope this helps..

Cool
-mikx
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mikx
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Joined: 05 May 2003
Location: Melbourne
PostPosted: Wed May 21 2003 06:31    
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by the way, joint stereo isn't linking up both channels to make mono.. c-frog was half-right about deleting stereo information at some points.. it's somewhat hard to explain so i found a radium codec faq (yeah good old radium!!) that has some answers..



Q : What's the difference between the various stereo modes?

A : It's important to understand the difference between Stereo and Joint Stereo. 'Joint Stereo' modes take advantage of the similarities between the L+R channels. This allows more bits to be used in other areas and in many cases this can give an overall gain in encoding quality. Almost all encoders use joint stereo when encoding at 128 kbits.

Joint stereo has 2 submodes called IS and MS. 'Joint Stereo IS' destroys phase information and shouldnt be used for high-quality encoding. 'Joint Stereo MS' means Middle/Side and is OK for use in most encoding.

However, for some audio, Joint Stereo MS may create a 'flanging' or 'swishing' effect. In these cases it's better to use 'Stereo mode'. This mode creates 2 independent channels for both left and right. When stereo mode is used, you should also use a higher bitrate (160 or 192 kbits) - Stereo mode will allocate about half of this bitrate for each channel.

In summary, for most audio, Joint Stereo MS at 128 or 160 kbits should be fine. If your audio is especially 'wide' and creates flange you should use 'Stereo' mode. You can change these modes in the Radium codec control panel.



i've found the difference myself, when i wrote that 'under the glacier' track.. it's got a synthline in which the phase is inversed.. now, with Joint Stereo i found the synthline to sound very swooshy and dropped out at times after encoding to mp3. Even at 256kbps. I changed the settings to encode in 'stereo' and it worked fine.

Cool
-mikx
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D Vibe
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Joined: 04 May 2003
Location: Sweden
PostPosted: Wed May 21 2003 08:42    
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em22 wrote:
c-frog wrote:
What I mean is that if you want as broad audience as possible, you should never just *think* that everyone has adsl, or that everyone understands your layout of your homepage. One of those things are for example using flash, and one other are not including a low bitrate stream for ppl with modem.


Yes, we know this - but if it wasn't for webmasters and other people creating sites that require a faster connections, and that keep pushing the requirements for a more powerful pc, we would all still be using Internet Explorer 1, Windows 3.11 and still banging out tunes using FastTrackerII with a GUS.

I myself submit tunes to a site which converts the tracks to a low-fi stream, at 24kbps 22khz mono. Which sounds fairly usless and kills the actual atmosphere of the track - and then it they create a hi-fi version, 128kbps standard MP3 specs - where the full glory of the track is present.

It's like that old debate about "why do I need a new computer?", "because old ones are crap", "but I can do everything I want here" - but then they constantly question people on how to overcome thier choice not to upgrade. I'm not saying you're annoying there by the way, just in case Razz

Just do 128kbps clips that will drop into winamp and then those on lower speed conections can wait a few seconds before hearing the track. Otherwise I don't know. I must admit I'm stoned, and I think I have lost my train of thought somewhere.

Where we talking about trips? Confused

;p


You do as you wish, but I prefer to not force anyone to get a computer with higher specs just because they should be able to listen to my music. As I said, the 56k-stream is only for previewing, if they like it, they'll prolly download the 128kbit version of it.

/Daniel


http://www.dvibe.se
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Pjo2000
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Joined: 05 May 2003
Location: Australia
PostPosted: Wed May 21 2003 08:43    
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c-frog wrote:
I believe joint stereo is fake stereo, which means that most of the information are saved on one mono channel and then adding the stereo difference in another one, which will for example cause less steps in the stereo.

Well, not hundered percent sure how it works, either not hundered percent sure how much bytes it will save Smile




http://www.modatic.net/audio/stereo_vs_jointstereo.php

some info on Stereo and Joint Stereo


http://www.projectoverkill.com
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Yannick
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Joined: 16 Apr 2003
Location: Belgium
PostPosted: Wed May 21 2003 10:43    
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If I'm not wrong, a same Vorbis stream could be used for different transfer rates. That's a nice feature of Vorbis vs MP3 (AFAIK MP3 doesn't support this).

So it may be interesting to learn about how to set it up.

Yannick
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