HydrogenAudio

Hydrogenaudio Forum => Listening Tests => Topic started by: SevenSystems on 2017-11-03 14:00:16

Title: AAC decoder in foobar2000 MUCH better than AVAudioPlayer's for low bitrates
Post by: SevenSystems on 2017-11-03 14:00:16
Hi,

first post! I'm just finishing the implementation of a "folder-based" music player app for iOS (a la foobar2000), and I'm noticing that when playing back low bitrate (~ 64 kbps) AAC-encoded streams (in M4A), foobar2000 on Windows sounds SO much better than iOS's AVAudioPlayer that it's night and day. AVAudioPlayer is totally muffled and almost unbearable.

Anyone had similar experiences? Any settings you can tune in AVAudioPlayer? What decoder does foobar2000 use, lame?
Title: Re: AAC decoder in foobar2000 MUCH better than AVAudioPlayer's for low bitrates
Post by: mpuzirew on 2017-11-03 14:55:32
LAME is ENcoder, not DEcoder. And moreover, it's for mp3, not AAC :)))
AFAIK, foobar2000 uses ffmpeg-based decoders for most formats. If a player is correctly designed, there must not be much difference from the others in sound quality. I don't know mush about AVAudioPlayer. Taking it for granted that it sounds bad at low bitrates, the only explanation that comes to mind - HE-AAC decoding implementation is broken. Lack of high freq as result.
Title: Re: AAC decoder in foobar2000 MUCH better than AVAudioPlayer's for low bitrates
Post by: saratoga on 2017-11-03 15:29:07
Aac-he or AAC-lc? If HE, make sure you are configuring SBR decoding or your results will be poor.
Title: Re: AAC decoder in foobar2000 MUCH better than AVAudioPlayer's for low bitrates
Post by: SevenSystems on 2017-11-04 15:00:11
Aac-he or AAC-lc? If HE, make sure you are configuring SBR decoding or your results will be poor.

Thanks for the heads up! I'll have to check if this can be enabled manually on AVAudioPlayer. The file is indeed SBR. There seem to be other people having similar problems:

https://stackoverflow.com/questions/45801960/aws-elastic-transcoder-he-aac-sbr-in-ios