Running Rockbox 3.1.3 on Clip+
Some HE-AAC files play back at half speed.
Example file info:
General
Complete name : Witness_-_The_Khmer_Rouge_take_power.m4a
Format : MPEG-4
Format profile : Apple audio with iTunes info
Codec ID : M4A
File size : 4.09 MiB
Duration : 9mn 0s
Overall bit rate mode : Constant
Overall bit rate : 63.5 Kbps
Album : Witness
Album/Performer : BBC Radio
Track name : The Khmer Rouge take power
Grouping : News
Performer : BBC World Service
Composer : BBC iPlayer
Genre : News
Recorded date : 2013-04-18T08:50:00+01:00
Tagged date : UTC 2013-04-18 09:07:25
Writing application : Lavf55.0.100
Audio
ID : 1
Format : AAC
Format/Info : Advanced Audio Codec
Format profile : HE-AAC / LC
Codec ID : 40
Duration : 9mn 0s
Duration_LastFrame : -1ms
Bit rate mode : Constant
Bit rate : 62.7 Kbps
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 48.0 KHz / 24.0 KHz
Compression mode : Lossy
Stream size : 4.04 MiB (99%)
The same file plays normally on PC players such as MPlayer, and on device such as Nokia feature phone.
I used ffmpeg to cut a 30 second sample (240kB) and uploaded it to:
http://www.mediafire.com/?7ej0ekac0gcv57g