Do radio People Understand Compression?

[bigtom101]

I think this hits the nail on the head...

You only need to read iBiquity's website and the "CD-like digital audio quality" and "digital clarity" claims for HD Radio to see how blatantly 'digital' has been used to misinform and misrepresent coded audio, by the marketing people.

And by that same token, satellite radio at one point was touting its sound quality...which even in the early days wasn't too much to write home about. Now with all the extra channels...yeech. Even worse.

I've heard some decent sounding HD stations...and I've heard some that were just "WTF?!?" - KC101 in CT for example. A station in HD near me, last time I checked, was feeding the output of a analog composite STL to the HD encoder. The blend from analog to HD is underwhelming to say the least - but since there aren't any HD 2 channels it sounds passable. The CC stations in NY have a strange "ssss" artifacting on HD, at least to my ears. The others in town don't. Much as poster above had to retrain himself using photoshop for photography, I think many of us have to approach processing for digital platforms differently. The "This Week In Radio Tech" podcast has a episode with Cornelius Gould where he talks about how to process for digital - very informative and worth a listen. I still need to get around to building a lightbulb compressor...

Shameless plug with a side story: my internet radio station "toy" is all digital - virtual audio cables handle everything from the automation output to the processing out to the encoder. I tried adding a complellor to smooth out the sound, but throwing in a D to A and A to D conversion ended up just adding some noise...and for some reason Breakaway didn't like having it (meters flashing red...even with the levels aligned - took out the compellor and all was well!). All the processing is on the same box as the automation - http://tunein.com/radio/Jammin-105-s141863/. This is digital done right - all the files in the NexGen are sourced from CD, uncompressed. The only bit reduction is the codec - pretty cool what you can fit on a desktop tower that used to take up rack space and needed physical patch cables. I'm waiting to get a updated encoder to go AAC+ - should sound better then...

 

[gtomas]

This is digital done right - all the files in the NexGen are sourced from CD, uncompressed. The only bit reduction is the codec

This is how it should be! As standard.

I'm waiting to get a updated encoder to go AAC+ - should sound better then...

Do yourself and your listeners a favor, and set it for AAC (not AAC+) at 128 kbps.


Regards,
Goran Tomas

 

[bigtom101]

Do yourself and your listeners a favor, and set it for AAC (not AAC+) at 128 kbps.

Regards,
Goran Tomas

Done...I switched from an older version of Simplecast to edcast to get AAC. I have 2 streams set up - one at 128k (http://jammin.servemp3.comAAC LC), and one for mobile set to 64k (http://jammin2.servemp3.comAAC HE).

On a related note...why after 10 years of more advanced codecs like AAC do people still love MP3's @ 128? And what codecs are on the horizon to replace AAC?

 

[gtomas]

Done...I switched from an older version of Simplecast to edcast to get AAC. I have 2 streams set up - one at 128k (http://jammin.servemp3.comAAC LC), and one for mobile set to 64k (http://jammin2.servemp3.comAAC HE).

Thumbs up!

You might want to try switching from 64 kbps to 48 kbps with HE-AAC. In my experience, it's not a significant difference in audio quality and if bandwidth is an issue, 48 kbps is cheaper.

On a related note...why after 10 years of more advanced codecs like AAC do people still love MP3's @ 128?

That's the one I would like to know the answer to, as well!

I've listen to the panel on an AES conference with people who invented MP3 and then AAC later on, and they were so desperate to realize a decade or so later, their first born child (MP3) got to be so widely spread and used, that the better codecs such as AAC have taken so long to get some traction... They discussed how they learned a lot with MP3 and corrected it's problems and weaknesses in AAC, but MP3 doesn't want to go. The other thing they were desperate about (and preaching to the quire) is the modem-speed Internet bitrate of 128 kbps that has became a de facto standard bitrate. Even today, when no body uses 56k modems any more and in the age of 8 Mbps ADSL, people still stick to the 128 kbps...

And what codecs are on the horizon to replace AAC?

There are newer codecs such as HD-AAC which combines lossy encoding with lossless encoding and I think that shows a way to the future. The bandwidth just keep getting higher and higher, there's fiber and dark fiber everywhere and even with the ADSL, high bitrate, high quality streaming is not an issue any more. Since in the future the bandwidth is just going to increase, I think the next step in streaming will be lossless encoding, maybe requiring about 800-900 kbps for full fidelity, no compromise sound quality

I mean 800 kbps is already only 1/10th of the common 8 Mbps ADSL download speed (at least in Europe)...


Regards,
Goran Tomas

 

[GeneSavage]

As a streamer who had to make the decision between mp3 & AAC, I can tell you why I chose mp3: just like Visa, it's accepted nearly everywhere.

If I use AAC, anyone coming to my page who ISN'T running Window 7 or better (98% of my visitors) won't hear anything when they load the page. If they click the Windows Media Player link, it will tell them it can't play it.

While there are plug-ins available, and both iTunes and Winamp support AAC, WMP is by far the most common and default player on most desktops. Most people are running Windows, most in fact are running XP, and they can't be bothered to figure out how to download a plug-in and install it and reload the page when there are 600,000 other stations waiting to be checked out.

As to why AAC isn't more widely supported, I think it is a licensing issue. You have to pay to use AAC decoders in your software, don't you?

There will come a time when AAC will hit critical mass, and I will switch to streaming in AAC. Sadly, that time is not today. If I could afford to run two streams, my second one would ABSOLUTELY be AAC for the mobile listeners.

...BTW, as far as 128 kbps being the standard, I got an email from a listener in France... said they loved our station because it was one of the FEW internet-only stations they could get from the US on Shoutcast that didn't stutter or freeze... "not once!"

I stream at 96 kbps.

 

[Chuck]

I share your concerns about AAC, even though it is obviously better than MP3. I too have experimented with running higher streaming rates using MP3, but it has ended up with many of our regular listeners saying that it stuttered and buffered. That's not good.

I've traveled to Europe several time in the last few years and noted that most Internet connections on the continent are much faster than you normally get in the USA. In Europe, higher streaming rates make a lot of sense. In the US, at least from an Internet point of view, I'm afraid we are a third world country. When you add cell phones into the mix, I'm finding that a stream much over 64 Kbs is not very reliable. Therefore, I stream at a lower than ideal rate. AAC might solve that problem at least for iPhone users, but I'm not sure if it works on other operating systems. Does Android do AAC?

I'd certainly consider changing to AAC, but I'm worried that many listeners would not be able to handle it. The obvious answer is to do two streams, but so far streaming our signal has been nothing more than a money loser. There is no apeal to doubling our costs. We are a traditional FM station that coincidentally streams. We do it mostly so our local listeners can have us on at work. It is nice to be able to supply a couple of hundred people in distant locations around the world with our programming, but they contribute nothing to the bottom line.

 

[gtomas]

There is a solution for concerns regarding playback of AAC. It's called Flash and it's been around for some time, as well...

If you build a Flash player in your web page that plays your stream, not only will it handle AAC, HE-AAC and other audio codecs, but it also doesn't require any separate player software to be installed on your PC. Your listeners will be able to listen to you no matter if they are running any variant of Windows, Mac OS or Linux/Unix. Just open a web page and listen. You can enrich your player if you want, with various other niceties or necessities, such as linking to iTunes and Amazon for currently playing items, announcing upcoming shows and game shows, pictures, twitter chat, Facebook and banners and commercials.

The only exception is iPhone - in terms of supporting Flash player, not AAC (Apple was one to support AAC LC in their players and devices early on). You can make a fall-back code in your web page for iDevices or you will probably want to make your own app anyway.

The other technology you can use is Windows Silverlight, but it looks Microsoft might kill Silverlight with Windows 8. Interestingly, iPhone does support Silverlight.

Both Flash and Silverlight might become obsolete once HTML5 establishes itself as a standard, as it will allow standardized audio and video streaming within all browsers.

There are no additional fees for AAC decoding that you as end-consumer would have to pay. Just like with MP3. In fact AAC is supported by the majority of players and it has been for at least 7 years now, including WinAmp, QuickTime, Flash player, VLC Media Player, foobar, etc.


Regards,
Goran Tomas

 

[Fieldtech1]

I dont see a need for streams over 128kbps as many wireless AND residential ISPs clamp down on excessive use and place caps on data consumption. Even on really good speakers, a well encoded 128kbps mp3 stream sounds 'acceptable' to me, and im pretty picky, so most user listening on little Logitech speakers at their desk will find is acceptable as well.

 

[PTBoardOp94]

Chuck Levins's "Pittsburgh Jazz Channel" uses 56 kbps AAC with Shoutcast. The quality is more than acceptable for listening on speakers at the office.

A station I consulted for got on the AAC bandwagon really early. This was when 56kbps internet was still common, around 2002. They encoded a 64 kbps AAC stream and a 24 kbps MP3 stream. The 24 kbps stream sounded like two tin cans. Turned out that people would rather complain about the AAC stream not working than use the bad MP3 stream.

 

[gtomas]

Rant mode on.

I guess it's a matter of different personalities, but I always strive to do things the best that I can. And as such, I strive to make a radio station sound the best that it can.

Which is probably why these kind of comments bother me. Now I understand technical and operating reasons such as re-buffering and streaming cost. Luckily, here in Europe we have forgotten about these. People watch "HD" (another marketing trick) videos on YouTube and elsewhere that are about 800 kbps, which makes a 128 kbps audio stream no issue at all, in terms of bandwidth and aggregated traffic.

But it's this attitude of "people won't notice" and "sounds acceptable" and "good enough" that I've heard so many times, that bothers me. Settling for less. Settling for acceptable. Settling for the lowest common denominator. I think this attitude is why we have so badly sounding radio stations today. It's this attitude of driving the quality down, or at best in the middle, rather than driving it high.

We don't need to use music in WAVs, MP3 sounds good enough... No body will notice. We don't need to buy the best processor we can buy, let's buy a cheaper one. "You think people listening in their cars will notice?" We don't need high quality streams - you think people listening on their laptops care?

We don't care, if we choose the acceptable.

People who care about music, don't listen on office speakers. They typically listen on headphones. A lot of people listen on headphones. And if anything, listening on headphones reveals much more audio quality issues and coding artifacts. Did you listen to your station's stream on headphones for a couple of hours per day? Can you enjoy the audio quality? Or do you after 3 hours find you can't listen any more because it is fatiguing? Try it.

Why do you choose to set the bar for the office clerk who makes coffee, and not music and radio lovers that listen to your station for the music and programming? They are trying to enjoy it, but you are not giving them opportunity. Personally, in this day of age, I wouldn't listen to your 56 kbps stream at all. There are stations that care and will give me a much better audio quality that I can enjoy. How many other listeners are you driving away?

You know, if you increase the audio quality, the office clerks won't care. People who really listen music and care about your station, will. The reverse, doesn't apply though.

Rant mode off.


Regards,
Goran Tomas

 

[rrsounds]

Rant mode on.

I guess it's a matter of different personalities, but I always strive to do things the best that I can. And as such, I strive to make a radio station sound the best that it can.
<snip>
But it's this attitude of "people won't notice" and "sounds acceptable" and "good enough" that I've heard so many times, that bothers me. Settling for less. Settling for acceptable. Settling for the lowest common denominator. I think this attitude is why we have so badly sounding radio stations today. It's this attitude of driving the quality down, or at best in the middle, rather than driving it high.

We don't need to use music in WAVs, MP3 sounds good enough... No body will notice. We don't need to buy the best processor we can buy, let's buy a cheaper one. "You think people listening in their cars will notice?" We don't need high quality streams - you think people listening on their laptops care?

We don't care, if we choose the acceptable.
<snip>
Regards,
Goran Tomas

Good rant, Goran. If you want to be able to claim to having a premium product, then you need to use your best judgment to take advantage of every opportunity to raise or at least maintain quality. Or you can go for the lowest common denominator. Depends upon one's life philosophy, I guess.

"Good enough isn't good enough." -Steve Jobs


Kind Regards,
David

 

[radiorob2.0]

I want to scream every time a radio station talks about HD radio and says "High Definition", it's not.

Our competitor is tone death regarding the issues of mp3's. Their oldies station aired a version of The Cordettes "Mister Sandman" that sounded like it had gone through a flanger effect as it had been mp3'ed to death. Their country station is airing a Rascal Flatts song that is obviously an mp3. You'd figure somebody would notice those songs sounded like ass but apparently not.

 

[GeneSavage]

Although I didn't say my stream was "good enough," I feel the need to respond.

I use FLAC files compressed from WAV files ripped from the best CD versions of the songs I have whenever possible.

I have made sure I'm running the bleeding edge latest alpha version of LAME's encoder in order to provided the highest fidelity with the current bitrate I'm using.

I've listened for hours upon hours of my stream via headphones to get the audio processing right where it needs to be. I find my stream LESS fatiguing than 99% of the FMs in town, and have received compliments from those within the audio processing industry (especially when they realized what I was using!).

I'd love to be stream FLAC, or at the least, mp3 320 kbps.

However, as a programmer of a 3kw FM told me once:

"people won't listen to what they can't hear."

When the infrastructure supports higher fidelity streaming, I will provide higher fidelity streaming.

In the meantime, I'd challenge you to listen to my 96 kbps plain ole mp3 stream, which (untrained) listeners have told me "sounds better than FM" and "sounds pretty close to CD."

You will be able to hear the difference; but I do NOT think you will be annoyed at how I've massaged the bits:

http://loudcity.com/stations/blacklight-radio/tune_in

 

[LibertyNT]

You know I've streamed at 96 kbps myself for awhile as well.
I just recently upped it to 128 and can't really tell any difference.

at one time I streamed at 32 kbps (years ago) and it sounded spectacular.

It's all about the processing.

most of my music files are mp3 or wav, I cannot tell them apart.

 

[Sgeirk]

To answer the original question: in a nutshell, no. Some do. The vast majority? Not.

Not everybody understood generation loss in the 80s, either.

 

[bigtom101]

As a streamer who had to make the decision between mp3 & AAC, I can tell you why I chose mp3: just like Visa, it's accepted nearly everywhere.

If I use AAC, anyone coming to my page who ISN'T running Window 7 or better (98% of my visitors) won't hear anything when they load the page. If they click the Windows Media Player link, it will tell them it can't play it.

While there are plug-ins available, and both iTunes and Winamp support AAC, WMP is by far the most common and default player on most desktops. Most people are running Windows, most in fact are running XP, and they can't be bothered to figure out how to download a plug-in and install it and reload the page when there are 600,000 other stations waiting to be checked out.

As to why AAC isn't more widely supported, I think it is a licensing issue. You have to pay to use AAC decoders in your software, don't you?

There will come a time when AAC will hit critical mass, and I will switch to streaming in AAC. Sadly, that time is not today. If I could afford to run two streams, my second one would ABSOLUTELY be AAC for the mobile listeners.

...BTW, as far as 128 kbps being the standard, I got an email from a listener in France... said they loved our station because it was one of the FEW internet-only stations they could get from the US on Shoutcast that didn't stutter or freeze... "not once!"

I stream at 96 kbps.

I thought about this, but since my station(s) are on Tune In & SHOUTcast, and hopefully soon iTunes, if someone found me they most likely have an AAC codec on their device (most BlackBerries, Android, and all iOS can decode various flavors of AAC). The only thing I need to find is a cheap/free flash AAC player for web browsers since Tune In is hit or miss with AAC.

I can notice the difference between MP3 and AAC, especially on a good stereo system - and at lower bitrates, AAC really does sound better than MP3.

I have my server with a very reliable stream provider in Italy - haven't had any trouble with them so far with buffering or latency issues. My broadband connection is FiOS, and so far I haven't had any issues with them either.

A properly processed MP3 stream at 128 will sound fine, depending on the source material and the encoder. Anything less (in stereo), and I start hearing the swishy coding artifacts. Maybe in another 3 years or so AAC will be the norm as all the Windows XP boxes start truly going away in the consumer arena.

 

[Sgeirk]

AAC+ is becoming a new standard, for sure. 64 kbps AAC+, when processed well sounds better than 128 mp3.

 

[RolfTaylor]

AAC+ is becoming a new standard, for sure. 64 kbps AAC+, when processed well sounds better than 128 mp3.

You will find many disagree with this statement. It will be better with regards to "swishies" for sure.

On the other hand, Spectral Band Replication (the "+" in AAC+) seems to have a wider variability that other types of coding artifacts with regards to perception. By this I mean that the average performance as measured in proper listening tests seems to less-accurately represent performance. I have not seen the numbers, but I would be wiling to bet the test results show a wider standard deviation that for listening tests of pure perceptual coders.

I base this on the fact I have never clued into the "synthetic quality" of the high end despite having spent _lots_ of time listening to AAC+ (during product development) on headphones and good speakers. On the other hand, I know of several people who's opinion I trust (Goran and Cornelius for example) who not only hear it, but find it very annoying.

AAC+ AKA HE-AAC has it's place, but it is appropriately used only in select cases (such as POTs codecs, Satellite Radio, or low bit rate IBOC etc)

Just MHO

R8)LF

 

[satech]

AAC+ AKA HE-AAC has its place, but it is appropriately used only in select cases (such as POTs codecs, Satellite Radio, or low bit rate IBOC etc)

IBOC / HD Radio does not use AAC+. iBiquity's "HDC" codec is claimed to be "based on" AAC+, but it is still entirely proprietary, and they have not released to the public the exact details of how it works. All we know is that it also uses SBR "fake treble", and performs similarly to -- although many say slightly worse than -- AAC+ at equal bitrates.

 

[gtomas]

AAC+ is becoming a new standard, for sure. 64 kbps AAC+, when processed well sounds better than 128 mp3.

You will find many disagree with this statement. It will be better with regards to "swishies" for sure.

<- - snip -->

I base this on the fact I have never clued into the "synthetic quality" of the high end despite having spent _lots_ of time listening to AAC+ (during product development) on headphones and good speakers. On the other hand, I know of several people who's opinion I trust (Goran and Cornelius for example) who not only hear it, but find it very annoying.

You are blessed!

Maybe it won't happen to you, though I suspect it eventually will... Once your brain "clues in" on the artificially synthesized high-end that always has the same texture to it, you will hear it every time you listen to HE-AAC. The higher bitrate helps to mask this a little bit, but it is essentially unavoidable with HE-AAC simply because the way the codec works.

Perhaps it's easiest to hear on the music that you really know well and listened to it on CD, that has a very nice and soft cymbals or hi-hat. If you are used to the original sound of the high-end and listen to it coded with HE-AAC (AAC+) even at 64 kbps or 96 kbps, you will hear the high-end that's completely different than the original. It will have harsh, metallic and "gritty" sound to it.

And if you play another song that in the original (WAV/CD) has a different texture of the high end, after being encoded with HE-AAC (AAC+) you will hear exactly the same texture of the high-end as in the previous song with soft hi-hats. That's the problem of HE-AAC. By design it's not transparent and it will never be and the high-end always has the same "gritty" texture to it.

AAC, on the other hand, can sound transparent and faithful to the original if used with at least 128 kbps.

HE-AAC creates an artificial high-end, which is how it can achieve wide frequency response at very low bitrates. That's what it was designed for. It was not designed to give high audio quality. It was designed to give wider frequency response at very low bitrates.

The marketing people and some manufacturers that use HE-AAC in their products, have then created this claim of 48 kbps or 64 kbps HE-AAC v2 sounding as good as _________ (fill in with whatever you consider good quality) to make a strong selling point. They've claimed (and still do) better than analog FM quality. Which is how 48 kbps HD Radio channels came about.

But it's not true and long-term listening will prove it. Just ask anybody who has listened to any form of digital radio that uses SBR technology in the encoder - HD Radio in USA, DAB+ in Australia, HE-AAC encoded satellite radio, HE-AAC encoded web streams...

We need to use higher bitrates (like 128 kbps) and codecs such as AAC in digital transmissions, to claim any level of audio quality that will match analog FM or CD quality.


Regards,
Goran Tomas