The Problem with Transcontinental Podcasting

RSS HeadphonesI am not sure if anyone else has to manage audio files that have been .mp3 encoded prior to editing but for the podcast it has been causing some issues. This week however, I made a few changes to the encoding and it appears to have made a significant difference. Here is what I have done and if anyone has any further suggestions I would appreciate it.

The background of this whole saga is that I used to record the podcast using Hot Recorder. Since the release of Skype 3.0+ this has failed to record anything but silence. Although he website claims it does work with 3.0. So we had to look to an alternative. Knightwise has a Mac so that made it a lot easier for us to decide what to do but our decision then presented a few things we had to work around.

For some reason recording Skype on a Mac is relatively easy compared to a Windows based machine. Not sure why. It might be the way that Mac handles audio or that there has been more development on the Mac in this regard. So we decided to record the show on Knightwise’s Mac. He uses Call Recorder to record Skype, which by the way has excellent results. Far superior to what I was getting with Hot Recorder. But now we had a great recording of the show in .wav which is generally about 1GB in size… +2.4GB but it was on the other side of the world! We needed to get it to Oz in one piece and in good enough quality to work with.

A great supporter of the podcast donated a server which has excellent speed and storage in addition to as many FTP accounts as we needed. However sending a 1GB file across the world is out of the question, even zipped up it would be huge! The only answer that we could see was to encode the .wav as an .mp3 in as high a quality as possible. So Knightwise encodes the file raw as a 192 kbps, CD quality. The result is about 100MB, which is very manageable. He then sends the file to me via FTP.

I download the file and convert it to a .wav and edit the show as per usual. When finished the file would be encoded as an .mp3 at 64 kbps at 44100 khz. We dropped the bps a while back to give us a smaller file size, which we thought would be appreciated. However since we swapped to Knightwise recording the show the 64 bit quality has been giving us poor results. I have tried to optimize for quality in the encode but it has made no difference.

The problem is that .wav files loose certain frequencies when they are encoded to .mp3. You can’t get them back they are gone forever. Sure I do everything that I can to get the best results. But the 64 bit rate was stripping more of those frequencies out of the final file than I would like. This resulted in some rather strange sounding ambient sounds and hissing when there was talking in addition to making the music tracks terrible. There was only one thing for it.

This week I increased the bit rate. Although in the beginning the show was encoded at 96 kpbs; I thought I would take the intermediate step of 80 kpbs. The result was a file that was only about 4-5 MB larger but the pay off in quality I think was worth it.

The conclusion is that when we changed the way the show is recorded and then encoded before transfer, we should have decided to increase the bit rate. The 16 bit increase in quality has compensated for the lost frequencies the first time it was encoded as an .mp3 making the file resilient to being decoded to .wav and then back to a .mp3. A few further tweaks at the recording end will give us some further head room as far as quality.

I would remind all podcasters out there of one of the golden rules of editing, never edit a .mp3, always convert it to a .wav. I hope this hack helps anyone else faced with the same problem of transcontinental podcasting and file transfer. Check out this weeks show and compare the difference.

UPDATE: Hot Recorder has been updated to version 2.14, which I am told does work with Skype 3.0+. I am yet to test it but I will let you know the results. Thanks to mswiczar for the tip in the comments.

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StumbleUpon Video… Yep It’s Good

StumbleUpon Video LogoStumbleUpon, is a great service that allows users to install a toolbar in their browser and “stumble” around the web. But rather than being random it sends you to sites that are A: Tailored to your preferences and interests and B: Where you go is constantly adapted and modified according to what you like and don’t like. The result is custom made surfing, good stuff. And them came video.

StumbleUpon is approaching 1.6 million users, most are fans. Although I have had my reservations. Now they are sure to add more to this number with the addition of video. You can log into the video page using your StumbleUpon log-in. Logging in means that your history is remembered just like with the original and the results get more in tune with your taste over the time you use the service. Although you do not have to log in to use the service, once you clear your cookies your results are reset.

The videos are sourced from YouTube and Google Video and I am sure that more services will follow. You can choose from different “channels” ranging from The Arts to Video Games. Watch a video and see which other users liked it as well, plus you can watch from their favourite videos as well. Can’t remember a great video that you watched? Have a look at your own history; what you have watched and if you liked it or not. There are options to share a video and send it to someone straight from the page. In my opinion there should a link that you can cut and paste into whatever communication that you wish to use, such as Instant Messaging.

The other thing that shines with StumbleUpon Video is the fact that you stop moving the mouse, everything but the video showing dims down giving you that “Cinema” feeling. Tops, I can’t wait to try it out tonight… That’s the kid in me. Nice touch though and attention to detail. There are no ads no commercials (so far). The fact that you don’t have to go anywhere and great content is “pushed” to you is the best thing of all. All making for a great user experience.

I agree with //engtech that to go to Google Video and YouTube is tedious in so much as the signal to noise ratio is way to high. Meaning that you have to sift through hours of rubbish to find gems. That has been much more the case as time goes on, if I ever see two teenage girls lip-syncing some crappy song again I’ll scream. With StumbleUpon Video that is hopefully a thing of the past. This is the cream of the crop from YouTube and Google Video in one place and not only that; as you watch and rate it, it gets better!

This is a sure winner. Video is the hottest thing on the Internet right now. People want this type of experience. Users like me avoid YouTube for all the rubbish but this makes it worthwhile and I am sure that my usage is going to go up because of it. The best ways to watch on-line video to date.

StubbleUpon Video Screenshot

Can I Change the Bit Rate of an Mp3?

I have seen this question come up a lot in the search terms that people use to get to Rooster’s Rail. So much so that I decided to answer the question here.

The short answer is no.

So I guess that deserves an explanation. Mp3 is an audio format that uses complicated compression formula that results in a much smaller file but retaining audio quality based upon what bit rate and sample rate was used to encode the file. Simply put:

Smaller file size = less quality

That is lower bit rate and sample rate.

Bigger file size = better quality

Higher bit rate and sample rate

Then there are mixes of the sample rate and bit rate that produces results that are in-between. There is also a file format called VBR or variable bit rate. I am not going to go into that here but that is basically where the bit rate varies according to the complexity of the music or audio file and results in a file size that can be smaller but retains a higher quality than an otherwise static bit-rate.

This bit rate and sample rate are dictated by the person that encodes the original file. The original file is often a .wav file wich is very large but of high quality. For example The Global Geek Podcast as a .wav file and goes for about one hour is over 500MB. Once encoded to an .mp3 file is between 20 and 25MB. I dictate the bit-rate and sample rate when I encode the file.

So lets say that you get that file which is encoded at 64bit and a sample rate of 44100khz. You want to lower the bit rate to make the file smaller. Sure you could using a program such as RazorLame, decode the file and then re-encode it at a lower bit rate such as 44bps (bit-rate). But the resultant quality would be lower than if I had used the original .wav file and encoded it at 44bps. This is because the best quality that you have is 64bps, that is as good as it gets. The quality can get no better than that. So in conjunction with the fact that .mp3 is a lossy file format and will get worse in quality every time it is opened and closed or encoded you end up with pretty much crap.

Same can be said if you wanted to go up in quality and therefore bit-rate. If you had a file that was encoded at 64bps there is no way on earth to make it better quality than what it is. If anything going up in bit-rate will make it worse because it will very successfully highlight the imperfections that are a result of encoding something as an .mp3 file. When a file is compressed in this way it decreases in quality regardless of the bit-rate. It all has to do with the fact that to make it a smaller file you have to ditch some of the data that the original file contains. That said it would take a very good ear to detect the imperfections in a high bit-rate encoded audio file, but it is there.

Moral of the story is that if you have an .mp3 file leave it as it is. Unless you can get the original source file there is no way to increase or decrease the quality and maintain any sort of standard about the quality of it. I hope this clears up a bit of confusion that there appears to be out there.
I tried to think of a good analogy to use for this post and could not, but this is the lame one that I did come up with:

Trying to change the bit rate of an .mp3 file is like baking a cake and then deciding that you want to know how to make it so it has less sugar in it than what you originally put in it and still have the cake!

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.

Odeo Cripples Functionality

Odeo LogoOdeo seem to be updating and improving their services every other day of late. However, it is not every day that you see such a great service actually remove a feature and make it harder for users to utilise their service. They have indeed done so and perhaps in doing so shooting themselves in the foot.

One of the great features that is available to Odeo users is to have an "inbox". If you were to place a button on your website, be it blog or some other site you have enabled your readers to leave you audio comments by clicking the link. They get taken to a page that has a recording interface, which is simple and easy to use and the result is great audio. You as the user of Odeo get that recorded audio in your inbox once it is sent to you. You are notified of this by an email.

Another great feature is that you can subscribe to an RSS feed of your own inbox! So this is a great way to receive feedback on anything. Including podcasts. Seb and I saw it as a great way to get feedback for Global Geek Podcast, so we set up an account. The advantage of getting audio as feedback is that you could go to your inbox once you were notified and click the new Odeo comment that was left for you. You can listen to it. But the biggest feature was that you could click a "download as MP3" button and download the audio comment and insert it into a podcast! The result was excellent and we loved it.

The ability to download the MP3 has been removed from the play window! So what the hell is Odeo thinking in removing this key functionality. It means that it is impossible to download the audio from the page to your local machine. Rather it makes it a pain in the butt to do it.

I found that there is a work-around but it is messy: Open Audacity, set the source to "stereo mix" get ready to hit record… Open the Odeo message that you want to record. Flip back to Audacity and hit record, nip over to the Odeo page and click play. Go back and hit stop on the recording when it has finished. As I said messy. In addition the audio that you end up with is less than ideal and requires a bit of editing.

I am utterly dismayed as to why Odeo have removed this from their site. The only thing that I can think of is that they want users to listen to audio, only from them and not from another source. Perhaps they were not aware that the service was being utilized in this way and they have done it ignorantly, I just don't know. Sebastian has suggested that perhaps they are beginning to think about implementing a pay service and this has something to do with it. But since when has any site reduced their services as opposed to offering more. We are not the only podcast doing this. I can honestly say that if this situation remains as it is; the blogging and podcasting community could deliver some negative press, big time.

Global Geek Podcast has mentioned Odeo on every show that we have done. Not only that there is a link on the Global Geek Podcast website to Odeo, there is a link to Odeo on Rooster's Rail, Seb's Random Thoughts and we have plugged them for their service and functionality since utilizing their service. It is not like we have not given back to Odeo. This I feel is the thanks that we get.

Global Geek Podcast have sent off an email to Odeo in regards to this issue and we await a response, I will let you know what we get back from them when and if we do.

Update: Please check out the Follow-up Story