Hi: I want to stream audio from my soundcard, but I'd like to apply some dynamic compression to it first (ala winamp's audiostocker plus shoutmuxer thingy). I heard rumours of compression in liveice, but Iv'e been told that this only works when it plays from prerecorded MP3, not the live input. I'd like to do this with darkice, but can't see how it could be done. I guess I'd either need to use ecasound or something to get the sound from the card, process it and then somehow pipe it into a streamer. But neither liveice or darkice would seem to accept audio via a pipe. I guess the other alternative would be to hack darkice to be able to insert LADSPA plugins, which would be a neat thing, but then there'd be the issue of configuring them which would be an interesting UI issue. any ideas? Geoff. <p> -- Geoff Shang <gshang@uq.net.au> ICQ number 43634701 Please avoid sending me Word or PowerPoint attachments. See http://www.fsf.org/philosophy/no-word-attachments.html <p><p>--- >8 ---- List archives: http://www.xiph.org/archives/ icecast project homepage: http://www.icecast.org/ To unsubscribe from this list, send a message to 'icecast-request@xiph.org' containing only the word 'unsubscribe' in the body. No subject is needed. Unsubscribe messages sent to the list will be ignored/filtered.
> Check i.e. ULTRA-DYNE® PRO DSP9024. We have a number of them for different > applications (streaming audio, studio, broadcasting), and work quite well. > Hope it helps. > AlfredoMARS Music has a sale on the Composer Pro (MDX-2100) at $99 I run one for one of my streams, and am going to buy a 2nd one for two others. Great units. Used to use it for the Pirate FM broadcast station. After the FCC smacked my hand my MDX-2100 found a 2nd life for our streaming audio. -- Ethan <p>--- >8 ---- List archives: http://www.xiph.org/archives/ icecast project homepage: http://www.icecast.org/ To unsubscribe from this list, send a message to 'icecast-request@xiph.org' containing only the word 'unsubscribe' in the body. No subject is needed. Unsubscribe messages sent to the list will be ignored/filtered.
On Thu, Apr 04, 2002 at 07:13:45AM -0700, Jack Moffitt wrote:> While dynamic compression makes the transmission 'smaller' on FM radio, > it makes music harder to compress by psychoacoustic codecs, and therefor > you might have somewhat of a quality hit, although I haven't tested > this.I have tested this to a limited extent. Jack is correct that the addition of compression and limiting will cause the codecs to work harder. Any audio processing will generate distortion in additional spectral energy as second and third harmonics that the codecs will need to try to figure out how to compress. You will start to hear more artifacts in the stream the more you compress, limit and clip. But this isn't to say you shouldn't do some processing. There are two reasons to audio process for streams; to prevent digital clipping and to reduce the dynamic range so the audio can be hear in noisy environments. Sometimes folks will process the audio as they like the "sound". Ideally, you would want to use a soft knee limiter to prevent clipping and perhaps slow automatic gain control (AGC) to help reduce the dynamic range. The Behringer (http://www.behringer.com) Composer Pro MDX2200 is about the cheapest bang for the buck (~$150) processor out there. I found that it takes a lot of tweaking to make it sound okay. You can't use the use it too much as it sounds pretty bad if you push it. If folks have a couple extra bucks, I would suggest looking at the Aphex (http://www.aphex.com) gear as it sounds much better but you can expect to pay about $250 for a used "Compellor" (AGC) and $400-$500 for a "Dominator" (limiter) on Ebay. Tim -- Snail: Tim Pozar / LNS / 1978 45th Ave / San Francisco CA 94116 / USA POTS: +1 415 665 3790 Radio: KC6GNJ / KAE6247 "It's a damn poor mind that can only think of one way to spell a word." - Andrew Jackson "What is wanted is not the will to believe, but the will to find out, which is the exact opposite." - Bertrand Russell, "Skeptical_Essays" --- >8 ---- List archives: http://www.xiph.org/archives/ icecast project homepage: http://www.icecast.org/ To unsubscribe from this list, send a message to 'icecast-request@xiph.org' containing only the word 'unsubscribe' in the body. No subject is needed. Unsubscribe messages sent to the list will be ignored/filtered.
> I want to stream audio from my soundcard, but I'd like to apply some > dynamic compression to it first (ala winamp's audiostocker plus shoutmuxer > thingy). I heard rumours of compression in liveice, but Iv'e been told > that this only works when it plays from prerecorded MP3, not the live > input. I'd like to do this with darkice, but can't see how it could be > done. I guess I'd either need to use ecasound or something to get the > sound from the card, process it and then somehow pipe it into a streamer. > But neither liveice or darkice would seem to accept audio via a pipe. I > guess the other alternative would be to hack darkice to be able to insert > LADSPA plugins, which would be a neat thing, but then there'd be the issue > of configuring them which would be an interesting UI issue.While dynamic compression makes the transmission 'smaller' on FM radio, it makes music harder to compress by psychoacoustic codecs, and therefor you might have somewhat of a quality hit, although I haven't tested this. jack. --- >8 ---- List archives: http://www.xiph.org/archives/ icecast project homepage: http://www.icecast.org/ To unsubscribe from this list, send a message to 'icecast-request@xiph.org' containing only the word 'unsubscribe' in the body. No subject is needed. Unsubscribe messages sent to the list will be ignored/filtered.
On Thu, 4 Apr 2002, Jack Moffitt wrote:> While dynamic compression makes the transmission 'smaller' on FM radio, > it makes music harder to compress by psychoacoustic codecs, and therefor > you might have somewhat of a quality hit, although I haven't tested > this.Quite possible, though I'm only using 56kbps 22khz stereo anyway so that's not such a big deal. I really need it to even out levels, however, which is more important to me. Geoff. -- Geoff Shang <gshang@uq.net.au> ICQ number 43634701 Please avoid sending me Word or PowerPoint attachments. See http://www.fsf.org/philosophy/no-word-attachments.html <p><p>--- >8 ---- List archives: http://www.xiph.org/archives/ icecast project homepage: http://www.icecast.org/ To unsubscribe from this list, send a message to 'icecast-request@xiph.org' containing only the word 'unsubscribe' in the body. No subject is needed. Unsubscribe messages sent to the list will be ignored/filtered.
Geoff Shang wrote:> Hi: > > I want to stream audio from my soundcard, but I'd like to apply some > dynamic compression to it first (ala winamp's audiostocker plus shoutmuxer > thingy). I heard rumours of compression in liveice, but Iv'e been told > that this only works when it plays from prerecorded MP3, not the live > input. I'd like to do this with darkice, but can't see how it could be > done. I guess I'd either need to use ecasound or something to get the > sound from the card, process it and then somehow pipe it into a streamer. > But neither liveice or darkice would seem to accept audio via a pipe. I > guess the other alternative would be to hack darkice to be able to insert > LADSPA plugins, which would be a neat thing, but then there'd be the issue > of configuring them which would be an interesting UI issue. > > any ideas?interesting indeed. can you tell me more about these LADSPA plugins? Also, the OSALP project is aiming for something similar. <p>--- >8 ---- List archives: http://www.xiph.org/archives/ icecast project homepage: http://www.icecast.org/ To unsubscribe from this list, send a message to 'icecast-request@xiph.org' containing only the word 'unsubscribe' in the body. No subject is needed. Unsubscribe messages sent to the list will be ignored/filtered.
Alfredo E. Cotroneo
2004-Aug-06 14:22 UTC
[icecast] Applying dynamic compression to live audio
At 00:01 05/04/2002 +1000, Geoff Shang <gshang@uq.net.au> wrote:>I want to stream audio from my soundcard, but I'd like to apply some >dynamic compression to it first (ala winamp's audiostocker plus shoutmuxer >thingy).It's not exactly what you ask, but these guys have tremendous sound processors, and quite cheap : http://www.behringer.com/ Check i.e. ULTRA-DYNE® PRO DSP9024. We have a number of them for different applications (streaming audio, studio, broadcasting), and work quite well. Hope it helps. Alfredo <p>--- >8 ---- List archives: http://www.xiph.org/archives/ icecast project homepage: http://www.icecast.org/ To unsubscribe from this list, send a message to 'icecast-request@xiph.org' containing only the word 'unsubscribe' in the body. No subject is needed. Unsubscribe messages sent to the list will be ignored/filtered.
On Thu, 4 Apr 2002, Alfredo E. Cotroneo wrote:> It's not exactly what you ask, but these guys have tremendous sound > processors, and quite cheap : > > http://www.behringer.com/ah. I forgot to say ... I don't have any money to spare on this. <grin> I'd like to have some hardware compressors one day, but I don't have the cash and anyway, since there's compression code already out there, I thought there should surely be a way to use it for this. I'd like to be able to switch over from using windows to using linux and this is basically all that's stopping me. Geoff. <p><p> -- Geoff Shang <gshang@uq.net.au> ICQ number 43634701 Please avoid sending me Word or PowerPoint attachments. See http://www.fsf.org/philosophy/no-word-attachments.html <p><p>--- >8 ---- List archives: http://www.xiph.org/archives/ icecast project homepage: http://www.icecast.org/ To unsubscribe from this list, send a message to 'icecast-request@xiph.org' containing only the word 'unsubscribe' in the body. No subject is needed. Unsubscribe messages sent to the list will be ignored/filtered.
> While dynamic compression makes the transmission 'smaller' on FM radio, > it makes music harder to compress by psychoacoustic codecs, and therefor > you might have somewhat of a quality hit, although I haven't tested > this. > jack.It took alot of tweaking to get ours sounding okay. We are running at a really low streaming rate (11khz, 22kbps) so that 28800 dialup users can hear the audio. It was hard to get the audio loud with no popping sounds, and still have some dynamics to it (where it isn't too flat). Most of what we are streaming is voice -- things go really downhill when music kicks in. -- Ethan <p>--- >8 ---- List archives: http://www.xiph.org/archives/ icecast project homepage: http://www.icecast.org/ To unsubscribe from this list, send a message to 'icecast-request@xiph.org' containing only the word 'unsubscribe' in the body. No subject is needed. Unsubscribe messages sent to the list will be ignored/filtered.
On Thu, 4 Apr 2002, Akos Maroy wrote:> can you tell me more about these LADSPA plugins?LADSPA stands for Linux Audio Developer's Simple Plugin API (see http://www.ladspa.org/). Basically, it was pointed out on the linux audio dev (LAD) mailing list that numerous programs were using plugin architectures and all were different. So they fleshed out a plugin API and the rest, as they say, is history. Right now, only things like compressors, expanders and limiters would probably be useful to insert into a stream, but if someone wrote an equaliser or a gate or something, that could well be useful too. Geoff. <p> -- Geoff Shang <gshang@uq.net.au> ICQ number 43634701 Please avoid sending me Word or PowerPoint attachments. See http://www.fsf.org/philosophy/no-word-attachments.html <p>-- Geoff Shang <gshang@uq.net.au> ICQ number 43634701 Please avoid sending me Word or PowerPoint attachments. See http://www.fsf.org/philosophy/no-word-attachments.html <p><p>--- >8 ---- List archives: http://www.xiph.org/archives/ icecast project homepage: http://www.icecast.org/ To unsubscribe from this list, send a message to 'icecast-request@xiph.org' containing only the word 'unsubscribe' in the body. No subject is needed. Unsubscribe messages sent to the list will be ignored/filtered.