On the Webcasting of Harvest Moon 2005
Part 1: The Concordia University EuCuE Series
The Harvest Moon Symposium 2005, held at Concordia University, saw the successful first attempt at broadcasting, live to the web, a series of panel presentations and concerts. It has been common practice for a number of years to record Concordia’s concert events for documentational, administrative and educational purposes. The international audience for an event such as this, a symposium on electroacoustic multi-channel works, was incentive enough to take the next logical step forward: webcasting both the afternoon professional talks and evening concerts.
This project was operated by Mark Corwin, technical director for the symposium. The technical process involved obtaining network permissions for running a server within Concordia’s network, setting up the audio recording equipment, sending the audio to the server, and testing the access from outside the network using a variety of client software.
Opening a network server to outside (Internet) access is a simple network technician procedure. The server layer is simply a computer running webcast server software, in this case, Nicecast for OSX. A component of the software compresses the audio signal into one that will fit the available upstream bandwidth of the network, and another component sends this data to connected users receiving the stream. The term “compressor-decompressor” is shorthanded to “codec”.
The Nicecast software is easy enough for someone comfortable with computers to use without having to read a manual, and allows audio input directly from external hardware, or from a running program that is outputting audio. The sound recording studio facility in the Oscar Peterson Concert Hall (adjacent to the conference room) made this setup process relatively trivial.
Technical Considerations
Listeners were able to connect to streams in MP3 format using software installed by default on Macintosh and Windows computers. Over the course of the symposium, successful connections were logged from Amsterdam, Dallas, Reston (Virginia), St. Louis, Atlanta, Mt. Laurel (Vermont), San Ramon (California), Banff, Toronto, Montreal, and Calgary. The audio quality ran at a standard broadband streaming bitrate of 128kbps / 44.1kHz. A low-bitrate codec such as MP3 is surely put through its paces in handling audio such as that recorded in a multi-channel electroacoustic concert!
Corwin reported, in particular, the compressor’s difficulty in encoding the heavy amounts of sub-100Hz frequencies in some of the pieces. Obviously, the sound quality can be improved considerably by increasing the bitrate, although this comes at the expense of higher bandwidth requirements, and upstream bandwidth is generally kept low for computers within a university network. MP3s encoded below 192kbps tend to show very obvious aliasing effects in noisy and acute high frequencies, a side effect that is amplified with room reverberation. A possible solution is to serve multiple simultaneous streams at different bitrates, allowing a limited number of higher-quality connections as bandwidth allows.
While streaming MP3 has been a standard for many years, superior low-bitrate compression formats have long since been available, and are now within the mainstream’s grasp in the form of built-in playback and compression options in ubiquitous OS-integrated media player software. Formats of considerably higher quality such as the open-source Ogg Vorbis (OGG) and Advanced Audio Codec (AAC) are now being implemented in web streaming protocols, but have been very slow to adapt, as the market demand for high-quality compressed audio is lacking.
It would be worth comparing software compatibility with different streaming codecs, as the non-MP3 formats (of which there are a growing number) tend to be less readable by a wide number of software packages across platforms. Companies marketing higher-quality compression technology tend to watermark them as proprietary to their own player software / hardware platform, a trend consistent with the recent corporate interest in implementing various degrees of Digital Rights Management (DRM) “protection” schemes embedded in encoded media files.
A more technically difficult setup can be achieved that would provide multiple streams in alternative codecs, each compatible with a specific common media player. This would involve using a different server application and a fair amount of time spent on configuration and testing. The capability of multiple simultaneous streams could also allow for broadcasting of multiple microphone pairs, each for specific listening environments. For example, a binaural microphone stream could be selected by listeners who are using headphones.
The two series of ÉuCuE (XXIV) concerts which took place in October and November were also webcast, mostly with success. The October series took place in the nearby Theatre and Dance building on the Loyola campus, in a “black box” space. The lack of recording facility demonstrated the flexibility of the webcasting system, in that Mark was able to record the concerts while sitting in the centre of the room using binaural microphones, and broadcast from his laptop. By the time ÉuCuE was back in the concert hall for November, technical issues were understood and the process was routine.
Podcasting
Another recent cultural-digital phenomenon, propelled by the success of Apple’s iPod, is what is known as “podcasting”. This technology, built on the concept of web radio, has been propelled forward by a market saturated with affordable digital music players. Not actually related to (or dependant on) the iPod, a podcast is simply an XML (eXtensible Markup Language) file, in plain text, that associates a URL with a name for an episode or broadcast. The success of the technology lies in the implementation in client software, which generally follows a subscription model.
The software will connect to this “feed” XML file, check for new broadcasts, and download one or more (depending on the user’s settings) broadcasts. This is not at all a streaming technology; the concept is that the broadcast can be listened to, or viewed (if it is a video broadcast), at any time, and automatically synchronized to a portable media player.
It would be possible to make electroacoustic concert recordings available as podcasts for distribution, where the media is browsable and downloadable right from within software such as iTunes. However, the shift in delivery method from broadcast to downloadable content would likely introduce new issues with regards to copyright.
Podcast subscription has been a feature of iTunes since May 2005, and alternate software is also available on all major platforms.
Part 2: Interview with Mark Corwin
Given that the software component of the webcasting system is very simple, what other technical and administrative barriers are faced in a situation such as the symposium webcast?
The biggest technical barrier was the University policy of blocking port 8000, effectively blocking all users of iTunes. I’d asked of a number of IT people about this and got nowhere. It seems Concordia is Mac-phobic in the IT area. From what I can gather, they allow RealAudio and other streaming programs, predominantly PC in nature, to stream audio through the system, but have some problem with iTunes. In any case, it meant posting a warning on the webcast page that users should paste in the URL into Quicktime or Windows Media Player to gain access. To be fair, I was told that, given enough lead-time, they would open port 8000 on their system for our next webcast. We’ll have to see: ÉuCuE XXIV.9–13 webcast comes February 8–10 @ 8:00. [Editor’s note: Webcast attendance for February’s series was slightly lower than has been in the past, with reportedly half a dozen intermittent connections and fewer persistent listeners. Player software was not this time identified.]
What has been the listener capacity, given that the streams are hosted from within a university network? Was bandwidth an issue?
I’m not completely sure on this one. I’d had 7–9 simultaneous listeners on at one point earlier in the year, but have no idea what the capacity is of 1) the network or 2) the web server — my PowerBook G4. At one point during the Harvest Moon Symposium, I logged 78 attempts to link to the webcast. I’m sure many of these were multiple attempts from individuals trying to get through iTunes. I had posted a request [on Concordia’s student] electroacoustic discussion list <eamt@concordia.ca> concerning failed attempts and got a number of replies, but mainly about iTunes-No, QuickTime-Yes.
From the feedback you received, were most listeners able to connect easily?
Most listeners who replied were kicked off before connecting, because most listeners tried to double-click the URL on the Webcast page and consequently launched iTunes — many (if not most) of the potential listeners were Mac-based.
What microphone configuration(s) were used in recording the webcasts?
We used a modified spaced pair omni arrangement for most of the Harvest Moon, but used a pair of OKM binaural mics for a few of the concerts where we were unable to secure a fast internet connection. The omnis were about 20cm apart, set slightly forward of the centre of the speaker array. I wasn’t satisfied with the pickup though. The Oscar Peterson Concert Hall has a 1.8s reverb, and this compromised the clarity of the pickup. The binaural mics were interesting in the way they picked up the projection, but the quality of the mics was/is evident.
With the recent development of Sonus.ca and now the webcasting of concert events, is there interest in publishing these recordings in a standardized, downloadable form (for example, a content system such as Podcasting, or integration into the Sonus database)? What issues would be involved in such an undertaking?
I’ve noticed a number of methods for distributing content of concerts, symposia, meetings, gatherings, etc. It seems to be too early though to really consider any one as being a standardized and agreed upon format/method. I’ve been listening to a number of podcasts as well as individual works on my iPod, through iTunes, RealAudio, etc. They all have viable elements. Accessibility is possibly the focus for a format consideration. For instance, it may be highly desirable to have a 5.1, or 8.1 full bandwidth work be accessible to the small number of high-end listeners, those who would be prone to seek out the high quality and would put up with download times (which become faster and faster each day it seems). On the other hand, a compressed 5.1 home theatre type file would give a broader listening base to the medium. Things are changing so quickly at this time. It really is quite exciting. In passing, I think the Podcast format will add a significant access point to our medium in the very near future.
The CEC’s extended use of electronic communications lends itself as a natural listener-base for the webcasts. Is there interest in aiming to bring in more listeners from outside the academic community?
At this point, we are happy to have our students and colleagues stream the concerts in growing numbers. Getting a wider listener base is a great idea, but to push the events out to a wider audience requires an advertising push that seems to yield far poorer results than the effort expended. Electronic adverts as we read over cec-conference is a very effective advert — for those who wish to listen and take advantage, i.e. appreciate, the sonic experience from the live venue.
Some Links Relevant to Webcasting
Streaming/formats
Apple AAC
Nicecast / Nicecast FAQ
Ogg Vorbis
Podcasting
Juice, cross-platform Podcast receiver
Events and Organizations
Harvest Moon Symposium
ÉuCuE — Electroacoustique
Electroacoustic Programmes at Concordia University (Montréal)
Other articles by Sutton
CD Review of Yves Daoust’s Musiques Naïves. In eContact! 6.2 — Activités Électroacoustiques au Québec / Electroacoustic Activities in Quebec.
Social top