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A
acrowne
Known Participant
April 27, 2011
Question

Distorted sound quality in AIR 2.6 on iOS

  • April 27, 2011
  • 2 replies
  • 2507 views

I am experiencing significant distortion of mp3 audio files (a child speaking) in my iPad app built with AIR 2.6. I have tested the audio files on the device in other apps, and can confirm that the problem is specifically with my app, not a problem with the audio file or the device. This is a critical issue for me and is preventing me from submitting my app.

I am using AS3, not Flex, and I am using a SoundChannel to play the file.  Does AIR software decode mp3s or is it using the hardware?  Are there mp3 compression settings that are better/worse for AIR audio?  I tried a 48kbps Mono file and got a little distortion, so I bumped it up to 96kbps Stereo and got a lot of distortion!

Anybody have experience with this? 

Adrian

PS.  I am completely unable to search by forum on Adobe's site.  I can use the general search, but once I am in Mobile Development there is a separate "Search this Forum" field, and that always turns up 0 results no matter what.  It would sure be great if this could be fixed so that we could find each other's threads better.

This topic has been closed for replies.

2 replies

C
chotgor1
Inspiring
May 6, 2011

I noticed it too. While testing FLVPlayback of a live stream, on iphone 3gs and 4 at the same time, the iphone 4 was giving that weird jittered audio and the same build of the app on 3gs was playing without any problem. I think on iphone 4, when I run a newly installed app for the 1st time, it was doing the weird audio then if I close app and open the problem is gone, or maybe other way. I was using CS5.5 with air 2.6.

The audio was mp3 / 48-64kbps.

I think it went away after I made some changes with GPU settings or the nativeapplication activate state etc, something not related to audio I made change and somehow it is gone. It was using retina display on iphone 4, so I assumeit was a cpu load issue.

I have that app built with cs5 and PFI and there was no audio issue like this.

I hope this helps , and thanks for great work.

S
sanika Kulshreshtha
Participating Frequently
April 28, 2011

Hi Adrian,

Thanks for reporting the issue. To answer your questions, AIR only uses Software decoding. Could you please elaborate what kind of distortion are you observing? Does the audio stutter or you hear noise? Is the sound file packaged along with your application? It would be great if you could send me a small application which demonstrates the problem, my id is sanika at adobe dot com. Also, is this an iPad only application. Would it be possible for you to try it on an iPhone/iPod and see if it is specific to iPad?

Thanks,

Sanika

A
acrowneAuthor
Known Participant
April 29, 2011

Thanks sanika.  I will see if I can put together a small test app demonstrating the problem, and in the process will see if it is iPad only or iPhone and iPad.  The distortion is high-frequency, almost static-like sounds.  I did not notice it as much when I recorded my own voice which is lower than the child's voice I used.  Anyway, I will put something together soon and send it over.

Thanks,

Adrian

S
sanika Kulshreshtha
Participating Frequently
May 3, 2011

Hi Adrian,

High-frequency sound is possible if you have recorded your audio was recorded using SPEEX encoding(which always uses 16 Khz rate), and are playing it using the sound object, which exposes the data at 44100 Hz. Could you please confirm the SoundCodec that you used while recording? You could try changing the SoundCodec to Nellymoser and see if it solves your problem.

Thanks,

Sanika

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