One discussion I don’t recall seeing here is that about audiofile formats. Now might be the right time to begin what could be an ongoing discussion over the next few months, based on “news to me” heard on THIS WEEK in RADIO TECH, with guest radio engineer Greg Ogonowski who specializes in streaming formats for everything from radio station delivery feeds to streaming radio stations over cell phones, iTunes and everything else. According to him, the format known as HE-AAC has come to be the best of the best for high audio quality in a low size package.
This link is a good starting point to learn about HE-AAC
http://en.wikipedia.org/wiki/HEAAC
Here at KDX we record in WAV, 22.05kHz, mono for our permanent master copy, convert to 56kbps, 22.05kHz MP3 for streaming, and stream at 24kbps, 22,05kHz, mono and 16kbps, 11.025kHz, mono over the internet. The MP3 stream is fed to FM 107.1 and AM 1550, and is better than AM wide-band to this listener’s ear, almost as good as the best mono FM. It is a sound intended for small loudspeakers in table and portable radios.
But having heard this latest news we are starting to investigate AAC, the format upon which HE-AAC is built, and wonder what audiofile experiences or thoughts you might have?
Formats
AAC+ is a variant from the H-264 which is used in movie DVD audio tracks and the HD Blu-Ray. It is also used in the HD video streaming format “MP4”
It is becoming the standard for mobile device media delivery because it requires very little bandwidth utilization for high quality audio.
KROCKS records in WAV at 64 bit sampling stereo for mastering, then converts down to 320Kps, 48Khz sample stereo for post production, then creates a finished master at the same bit rate and sample rates in stereo.
For on air playback I convert the finished production 320’s down to 256Kps 44.1Khz stereo and for distribution via podcast the file is converted down to 64Kps, 22050Khz stereo.
Our streams consists of 3 24/7/365 feeds. A 100 slot 128Kps 44.1Khz stereo, a 100 slot 48Khz 22050 stereo and a 300 slot 24Kps 44.1Khz stereo AAC+.
RFB
Useful info guys. Thanks!
Useful info guys. Thanks!
AAC
AAC was specifically created for low-bitrate streams
at higher Bitrates AAC us practically useless,
you’d might as well be MP3.
The folks with 128 kbps AAC are doing that just to seem fancy.
I think the conversion is something like this
25 kbps AAC = 128 Kbps MP3 quality.
But keep in mind, most everything plays MP3,
not everything will take AAC.
Wasting
The folks with 128 kbps AAC are doing that just to seem fancy.
I think the conversion is something like this
25 kbps AAC = 128 Kbps MP3 quality.
That is indeed an accurate observation, and quite a waste of the purpose of what AAC was designed for. Running AAC or AAC + on any bitrate higher than 96Kps is really defeating the purpose for what ACC and AAC + was written.
Slowly more players are becoming AAC/AAC+ compliant. For example, players that already come “factory ready” are:
Winamp
Windows Media Player
Real Audio Player
VLC Player
The Flash player cannot by itself decode an AAC or AAC + STREAM. It can play AAC/AAC+ files. In order to have Flash play AAC/AAC+ streams, the requirement is a 1K price tag server program which uses RTTP protocol, or Red Hat.
The reason is that AAC/AAC+ has a slightly different header bit than regular MP3. When a player connects to a stream server, the defining bit first sent by the server upon connection of any player defines the stream type. Flash will make the connection to an AAC/AAC+ stream, but will simply sit there and not know what to do next because the base Flash player does not recognize that identifier header bit. You will see the Flash player connect, its timer count, but further than that..it does not know “how” or “what” to do with the data feeding into it..resulting in no sound.
Some software developers have written Flash based players that “fake” the header bit so the player knows what to do. However they do not just give it away, it comes with a price, almost as expensive as the Adobe RTTP server program!
The best “default” to go with when choosing an embedded player for a website to play an AAC/AAC+ stream is the one that is already incorporated into all Window’s platforms…Windows Media Player.
RFB
VLC Anyone?
VLC is a very sophisticated free media player.
The first time I saw the three letters “VLC” was in the connection line on my Shoutcast Server window, where other people connected with Winamp or other media players.
But lately I was looking for something to playback some Flash videos, and it turns out that VLC will play back anything, audio, video, you name it.
Since earlier posts in this thread talked about HD-AAC v2, the audio format, I haven’t yet tried to play that format with the VLC Player, but I bet it’ll do it. I recently began streaming in AAC and do know that the AIMP free player will capture AAC streams. Write that down.
But after all this talk I haven’t reached this point – let’s hit the Reset Button.
As you know, Audio Players can be used to receive streams, podcasts, audiofiles… or SEND a playlist to a transmitter or stream and thus form the foundation of a radio station!
Case in point, my playlist for KDX Worldround Radio is sent from a Winamp Audio Player, and as you know many people use Zara to send their programs.
Question: can the VLC Player be used to transmit radio programming?
I am asking because you may already know.
I am only starting to sniff around the VLC Player and will eventually figure it out.
Goodbye for now.
Winamp plays AAC
Winamp has played AAC for many years. It’s in the file associoation menu.
AAC on VLC
Yes, PhilB, Winamp is capable of playing AAC streams.
And we may now add VLC Media Player to that list, I easily got it to receive the HD-AAC v2 stream from my server.
This is useful information for those streaming in AAC mode, as listeners will need to use a compliant media player to access the stream.
A few years ago some of the media player software didn’t respond to MP3, but that changed very fast as MP3 became so popular.
Winamp Status
When sold by Nullsoft the Winamp download became unavailable for awhile, except for a few download sites who offered a Winamp download without listing version information, making me suspicious of those sources.
But the new owner, Radionomy, has posted an announcement
http://forums.winamp.com/showthread.php?t=374929