What Bit Rate for Podcasts?

I really, honestly do not know the answer to this question. What is the best bit rate to encode a podcast at? Also does that answer depend upon the fact that you are a listener or a podcaster or hosting service?

I do the post production work for the Global Geek Podcast. Before moving to TPN I always encoded the podcast at 44khz and 96kbps. That works out at about 35 – 40MB per show (depending on length between 40 minutes to an hour). We have what I think is great audio quality, but am I spoiling ourselves and our listeners and potentially excluding others?

We have never had a complaint about the file size of the show. No-one has ever said it was too big. People have commented on the quality and said it is great and we have worked hard to get it that way. But I now question if that is over kill. So I tried to figure out what bit rate is the most common. I did a very small survey of the podcasts I have on the computer. I only have nine on it at the moment – most of them are on the MP3 Player (where they should be).

Anyway I got the following breakdown:

Total of 9 Podcasts:

  • 2 encoded at 96kbps
  • 4 encoded at 64kbps
  • 3 encoded at 48kbps

A conclusive survey that does not make. But maybe I am aiming too high. What quality do listeners expect of a podcast? Do they want a small file and lower quality so that they get the content without the bandwidth. Or do they want great quality and a larger file size? With the size of MP3 players now the storage is not an issue I don’t think. But I know in Australia the cost of bandwidth might be. The cost of faster connections is expensive and so many users are on a maximum of 256/64 or 512/128. So does a larger file size deter them from listening to our show? Could we have a bigger audience if we made it smaller and if that is the case what size is acceptable?

With the uptake of broadband technology there is a step towards encoding at a larger bit rate but what should it be? Perhaps 64kbps is a good place. I listen to quite a few podcasts that are recorded at 64kbps and they sound good. A one hour podcast encoded at 64kbps is about 28MB (voice only). Is this a big difference to 96kbps? Well it is between 10 and 15 MB. Will that mean the difference between more listeners and a balance between keeping your existing ones because of what they expect? Will you loose listeners by lowering the bit rate dramatically and will it matter because of the number you pick up. To me it does anyway, I care that we keep the listeners we have.

The other big consideration here is the hosting cost. I know that I had to go to the plan one up from the basic plan in order to have the podcast encoded at such a high bit rate. So that privilege cost me $10US/month instead of $5US/month. That was a cost that I thought was worth it. Also what if your podcast is being hosted by a network, what file size is reasonable for them to host? Is it acceptable that you have a higher bit rate than the other shows that are hosted there and is it necessary? Personally, I would like to find a happy medium between file size, bit rate and quality. I want the best quality at a reasonable file size. I don’t want my hosting provider to get pissed off that the show is too large. In addition to that fact; the network wants as many people to listen to as many shows as possible. If it is possible that people are “turned off” by a large file size, then that is not for the benefit of the network and I would not do it. In that instance the file size should be smaller at the sacrifice of quality for the benefit of the network and I need to accept that.

As a listener I do not care what size a file is. I have a fast Internet connection and it really does not bother me. I like high quality podcasts but I listen to some that are not of a high quality as far as bit rate because the content is good. So is good quality a cover for shit content? If it is; it is not sustainable long term. So as a listener of podcasts I don’t search for podcasts based on audio quality or file size, and maybe I have just answered my question in part.

Having made these points I will say that some basic editing will improve quality out of sight. I have turned off podcasts because they have not bothered to do this basic editing. They were unlistenable and total shit and they should have thought the same! I wonder if some podcasters even listen to it after they have recorded it. So what do I mean by “basic editing?”

Basic editing in my opinion is:

  • Setting levels before you start, especially if you are recording Skype using a software application. This means setting your levels with enough “headroom” to get loud during a podcast so that you don’t “clip” the recording. And not so soft that you have to amplify it dramatically to get something to work with.
  • Don’t edit the podcast as an MP3, MP3 is a “lossy” format and gets worse and worse in quality every time you re-encode it or open it and save it.
  • Run a compressor on the audio to “smooth” the audio. That is take out the high’s and bring up the lows.
  • Run the compressor a few more times.
  • Normalise” the audio, basically set the zero level. Makes the podcast the same volume and means that the listener isn’t constantly turning their volume up and down.
  • You may need to “amplify” the whole audio after using the compressor and normalising the audio. You don’t want the listener running out of volume because it is too soft!
  • Any added or imported audio needs the above steps.

Believe it or not the above takes the least amount of time in my editing but makes the biggest difference. I do go a step further and edit the actual audio and take out the umms and errs and we always stuff things up and say well we will edit that out. The time is also in the transitions and the mixing of the imported audio, making it all work together (the best that I can). So maybe you can see why as a podcaster I want it to sound as good as I can, I put a lot of effort into both the pre and post production. But is that at the neglect of other issues? Is this basic and advanced editing enough to make it a “quality” podcast?

Please leave a comment and tell me what you think. Tell me if you are a listener or a podcaster. Podcasters, tell me what you encode your podcast at and why. Listeners please answer my questions for me. As I said at the start of this post I really do not know what the right answer is, that’s why I have posed lots of questions. It would be great to get some answers, although I am not sure there is one.

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Global Geek Podcast Number 8 is Out Now!

Hey everybody, just letting you know that the latest podcast is out. Sebastian and I had an absolutely great time preparing for it and doing it. In addition to that we have worked on the audio and we think that it is much improved.

This week we did some things that made a big improvement to the audio, for a start Sebastian bought a mixer and a great microphone (check out the set-up here). I really need to put some photos up as well. The other thing is that I tweeked my audio to try to eliminate some of the background noise that I can not avoid. My computer sounds like a 747 taking off! But here in the tropics you need that as it gets pretty hot. So to do that I turned down the gain and had the microphone very close to my mouth. What do you know it worked. Don't know why I didn't do it before. But I think one of the reasons was that I was not that good with the levels and could not get it right. So I am glad that my skill has improved and I managed to get it so that it sounds good.

Sebastian's additions to his set up has made setting the levels for the show much easier. The reason being that using a mixer on line-in means that you over-ride Skype trying to adjust your audio setting as well as the fact that you can push the sound higher than you would be able to otherwise. The result is that we had a podcast in the raw format where the levels were pretty close. That ment that I did not have to "compress" it much or amplify it nearly as much. The other thing that we did before the show this week was we forwarded Skype on our routers, without going into it; that means better audio and no use of super nodes – rather a forced direct connection. It was an absolute pleasure to edit.

Sebastian was a bit disappointed with the result, he thought it would be better than it was. But as I said to him, look at how we are recording it; we are using Skype, then Hot Recorder to record it. Then after editing it I am encoding it as an mp3, inherently a lossy format and looses some quality in the encoding. Factoring all that in I think that comparatively we have a very good sound, especially if you get out there and have a listen to some podcasts out there that I don't think spend any time or effort on their audio.

Just a note for our regular listeners to Global Geek Podcast that there will not be a show released over next week end as Sebastian is going to South Hampton for inspiration. But we will hopefully be getting a show out mid week next week as the following week end I am working and it is a big effort to get anything out. So It will work out anyway.

Don't forget to check out the podcast if you have not already and don't forget that you can listen to it straight off this page just find the "PODCAST" button on the right and it stream off the site for you.

Eight Bucks Worth of Advice

Not very happy today. I went to the doctor and it turns out I have infected sinuses. In addition to that I went to the music shop to try to return an audio cord that was faulty. In addition to that I thought I had found a solution to record Skype which worked yesterday and does not work today! In addition to that I had a weird thing on my back biopsied cause the doctor was concerned it might be something "nasty". In addition to that my Line Out on the computer is stuffed.

So I feel like crap. The doctor put me onto some antibiotics to clear up the infected sinuses. Still copious volumes of what can only be described as primordial ooze continues to inhabit my sinuses which refuses to budge. This in turn is causing a headache from hell that is immune to paracetamol. I sincerely hope that it improves by tomorrow. The results on the suspicious thing is pending pathology.

So today I went looking for some digital speakers (I have SPDIF on the sound card as well) and I check the shop that I got my audio gear from. They like every other shop in Cairns does not have Digital Speakers. The guy in the shop did suggest a couple of things I could do to fix the plug in the computer. But while I was there I tried to return a cable.

When I bought my mixer, a Behringer UB 1002FX, I also bought a stereo to RCA cable. When I got it home I noticed that where the two cables can be pulled apart to reach connections the insulation had split. So I took it back to the place that I got it from and showed him what had happened. When I got this cable there were none on the shelf but the guy that served me managed to find a used one out the back that he gave me a 10% discount on. So today this other guy in the shop says:

"… ahhh well we probably sold you that cable with a discount to boot"

So I guess that means that because I got it at a discount it is okay that it is faulty, which is pretty much what I said to him. He then said that even though the wires were showing the cable would work fine. So I guess that means that it is okay that it is faulty because it still works… So then I said that I thought he should take it back and give me a refund due to the fact that the product was not right and that it was not acceptable. I also said that I was actually charged about full price for it. To that he dropped the clanger:

"Well I reckon that you have had about eight bucks of advice this afternoon"

I just walked out. What a wanker. This is no way at all to treat a customer, at least one that you want to come back. I was so shocked at this reply. I will never return to that shop. I am not going to spend any more time blogging about a looser.

So the other thing that I have been doing is trying to find a better way of recording Skype. So I had this brainwave yesterday. I will have to do this in point form:

  1. Connect the speaker out on the computer to the mixer CD/TAPE in.
  2. Connect the headphones to the PHONES socket (so I can hear everything)
  3. Press the CD/TAPE TO MIX button

Without pressing the CD/TAPE TO MIX button I can hear the other person and myself by turning up the volume on the mixer for the phones. But I have to press the "TO MIX" button to record both people in the conversation.

This indeed works, by recording the audio in Audacity. Well it worked yesterday. Today for no apparent reason the other person can hear themselves like you can when you select the stereo mix button. This makes no sense at all. As far as the computer is concerned all the audio is coming from the mixer to the line in as one signal. But for some reason I am getting a stereo mix as the result. Yesterday on the other hand it worked, perfectly. I have no idea why it worked yesterday and not today.

Back to Hot Recorder. And my infected sinuses and a buggered socket on the computer and a computer that acts as it computers do. Without logic that is, so condition normal.