We have a 3GPP Test/Development Audio Only HE-AAC/aacPlus Stream with
Packet Optimization running here:
For comparison, here is the Standard Non Packet Optimized Stream:
This stream is 32kbps HE-AAC/aacPlus Stereo encoded with Orban
Opticodec-PC using the genuine Coding Technologies Encoding
Libraries. The stream will play using QuickTime 7, however only the
core AAC portion of the stream will be heard, without SBR, as
QuickTime 7 does not support HE-AAC/aacPlus, only AAC.
The important aspect of this stream is that it is packet optimized,
such that as many AAC frames as possible are stuffed into a RTP
packet based upon specified MTU size, resulting in higher streaming
efficiency. For the example 32kbps stream, the network throughput is
reduced to about 33.5kbps from a non packet optimized stream of about
39.5kbps, saving about 6kbps or 15%. If you multiply this by say 1000
streams, it is 6Mbps down the drain! This is room for about another
175 streams, not to mention the increased reliability of data
delivery to the mobile device because of increased efficiency.
Crowded 3GPP mobile networks need all the help they can get, as
everyone is now finding out. 3GPP uses LATM transport for audio only
streaming for increased efficiency. Efficiency can be increased even
further by supporting multiple AAC frames in the 3GPP player
application. So far, I have not found one 3GPP mobile device player
that supports this. Thank you QuickTime developers for getting this
right! HE-AAC/aacPlus would be a welcome feature as well.
I would be very interested in other test results with these streams,
particularly devices that can play the packet optimized stream.
Although the streams are HE-AAC/aacPlus, they should play on AAC
players as well, except without SBR.
Greg J. Ogonowski
VP Product Development
ORBAN / CRL, Inc.
1525 Alvarado St.
San Leandro, CA 94577 USA
TEL +1 510 351-3500
FAX +1 510 351-0500