Bitrate, as the name implies, describes the rate at which bits are transferred from one location to another. In other words, it measures how much data is transmitted in a given amount of time. Bitrate is commonly measured in bits per second (bps), kilobits per second (Kbps), or megabits per second (Mbps). For example, a DSL connection may be able to download data at 768 kbps, while a Firewire 800 connection can transfer data up to 800 Mbps.
My daughter, a 12 year old fifth grader, just got into vinyl. Its my fault. The English department I work for was tossing a perfectly good record player, so I brought it home, and she, upon hearing and seeing it, commandeered it. I grabbed my dad’s country western, gospel, and sixties LPs I had stashed in the attic and picked up a copy of the Go Gos at a local flea market; she’s had the beat ever since.
I have a radio DJ friend who only buys vinyl with the sheer belief that the sound heard from vinyl is more pure and more pristine. And compared to current digital counterparts, he’s right. And most of us don’t care.
Typical Bit Rates
So how does this translate for podcasting? And what does this mean for podcasters? Podcasters are really concerned about two things when it comes to bit rate: the sound quality and the file size. These are the things that matter at least to me.
The higher the bit rate, the better quality the sound. This might make a podcaster be tempted to go for the highest quality mp3 possible. Who doesn’t want to sound good? But there is a catch. High quality come with a price; in this case the price is in file size. And file size matters for two reasons.
First, larger file sizes take longer for a listener to download. That means it is using more of their bandwidth and taking them longer to get to your content. Not a good thing. That means it is also taking longer for you to upload the file to your file hosting service. For those of us with time poverty in our lives, this is time we do not have.
Second, most of us pay a podcast hosting service like Libsyn or Podbean to host our media files. We pay for a certain amount of virtual storage space for our mp3 files. The larger our files, the quicker our hosting space will be used up and the more we will pay to host our files. Not good for the economically minded podcasters.
The thing you must ask yourself is what listeners really care about and what they are willing to tolerate when it comes to bit rate. This really depends on what type of podcast you are running.
If you are releasing a music podcast, most listeners will be ok with a 128 kbps. It is a tolerable quality for music that most listeners have gotten used to from burning their own Cds. If you create an hour long podcast of music, that will take up about 56 MBs of space. If you truly want to release near CD quality music in your podcast, you’ll be exporting your files at around 320 kbps, using 141 mBs of space for an hour long podcast. That’s a heck of big podcast and a heck of a big download. That seems a bit overkill.
A majority of podcasts, however, are spoken word podcasts and need only 64 kbps to produce a good sounding podcast. That only use 28 MBs for an hour long podcast. Most listeners as they are traveling on their commute, running along the road, or mowing their lawn will not know a difference.
So when thinking of bit rate, consider file size, the quality of file you’re ok with, and your audience expectations. For more information of bit rate, please visit here.