As part of my Day Job at IBM, I've been reading up a lot on Amazon's Simple Storage Service, aka Amazon S3 and at the same time, I've been planning and scheming on the relauch of my music podcast for Taproot Radio. One of the services I've been looking at the most is libsyn.com. It occurred to me that it might make sense to use Amazon S3 for hosting the MP3 files for the podcast instead of libsyn, so I decided to do some back of the envelope calculations to compare the two.
For the purposes of my podcast, I made the following assumptions:
-- I'd put out a podcast episode each week. This is extremely optimistic, but a good goal
-- Each episode will be a 30 minute music/talk episode recorded at 128Kbps and 44.1Khz for an average episode size of 28.8Mb per episode. (This is using libsyn's estimation guide).
-- I'd keep 2 years worth of episodes online at all times
-- I'd plan on 1000 downloads per episode. For an amateur hoobyist podcast, I think this is super optimistic, but a good goal.
Libsyn Costs for MP3 Hosting
Estimating Libsyn's costs are easy. You use this chart to figure out how much storage you need per month, then look up the price plan that matches your storage needs.
For my planning assumptions, I would fit into the $10/month "Podcast Standard" Plan.
Amazon S3 Costs
Amazon's S3 Costs are much more complicated becuase they charge you a) for each "put" request to get a file into their system, b) storage used per month, c) each "get" request to download a file, and d) "transfer our", i.e. Mb downloaded per month.
Their price sheet is online here.
Using the assumptions above, I create a spreadsheet in Google Docs to calculate the Amazon S3 costs:
So using my podcast planning assumptions, I'd estimate the Amazon S3 costs to be about $22.12 per month, which is more or less twice the cost of libsyn.
Because on eof the main value propositins from libsyn is:
"We don't want you to be penalized if your program gets popular. That is why we do not charge for bandwidth usage or for hosting of a static amount of web storage. Instead, our price model is based on how much space you need." I decided to look at what point you start getting penalized by hosting with Amazon S3 due to their "traqnsfer out" fees.
Fiddling around with the spreadsheet I came up with this:
So if I plan on 430 downloads per episode, instead of 100 downloadas, the price per month becomes more or less equal to the price of the Libsyn Podcast standard account. Or to put it another way, I start getting "penalized" for having a popular podcast when the downloads exceed 430 downloads per episode.
I would _love_ to know what the distribution is of number of downloads per podcast episode for all the podcasts libsyn hosts. I'm completely guessing but I bet there's a long-tail effect where only a very few podcasts have large nubers of downloads per episode and where the vast majority, like 95%+ have only a very small number of downloads per episode. I'd be willing to bet that this distribution is exactly what libsyn counts on for making a profit. Not that there's anything wrong with that.
Because at the end of the day, what you have to realize is that this analysis only compares MP3 hosting services. Libsyn's real value proposition is in all the other stuff they provide to make podcast production easy and fun. The MP3 players, the RSS feed generation, the directory, the podcast blogs etc. So they count on most of the podcasters paying a little more at libsyn than they'd need to pay for MP3 file hosting at some other service like Amazon S3 in exchange for all the groovy podcast production tools they offer and the promise that if the podcaster really does get popular, libsyn will eat the bandwidth costs.
That sounds like a good value proposition for the amateur podcaster like me.