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Douglas McCarroll
Douglas McCarroll
Inspiring
December 2, 2013
Answered

Is Voice Playback broken in AIR?

  • December 2, 2013
  • 2 replies
  • 4199 views

Hi All,

As I reported previously (here) it appears that voice playback is broken in AIR, i.e. voices with certain frequency profiles are played back with a distinct and unpleasant ringing noise added to them.

I've created this bug, and included a 'simplest case demo' that clearly shows the problem:

https://bugbase.adobe.com/index.cfm?event=selectBug&CFGRIDKEY=3651790

The bug's status has been "ToTest" with a reason of "NeedMoreInfo" since mid-October. The demo that I included should make this issue quite easy to test and confirm, and I've replied to the one question that Adobe staff asked, so it's unclear whether "NeedMoreInfo" is accurate.

Perhaps Adobe has other priorities, and doesn't consider voice playback to be essential to a framework focused on games, but audio playback seems like pretty basic functionality to me. I'm concerned that it has somehow fallen off of Adobe's radar.

On the other hand, I'm also concerned that I may simply be doing something incorrectly in my code. Might someone on this list might be willing to take a look at the demo project attached to the above bug (demo is here) and either confirm the problem or tell me what I'm doing wrong?

Note that the audio file contained in the demo is the worst example that I've found, i.e. the voice's frequency profile causes significant ringing when played in AIR. If you listen to the MP3 file that is included in the project directly, i.e. without AIR, you won't hear the ringing.

Help?

Douglas

This topic has been closed for replies.
Correct answer Colin Holgate

I'm converting an 96 Kbps WAV file. When I open it in Audacity the project rate is 96 Kbps. But when I export the file as an MP3, the export dialog's Options button takes me to a dialog that seems to determine the bitrate of the MP3 file. There's no 44.1 Mbps option there.

This happens even if I first change the project rate to 44.1.

But, no problem, I've found an app called Total Audio Converter that offers a 44.1 Mbps MP3 option.

I'll test with both 44.1 and 128 versions tomorrow and report back.


You’re getting mixed up. The sample rate wants to be 44.1 KHz, and you can choose that in the Project Rate menu in the bottom left of the Audacity window.

The data rate is something else, and that ought to be 128 kbps.

Using 44.1 kbps as a data rate would be poor quality.

So, your final sound will be 16 bit, 44.1 KHz sample rate, 128 kbps data rate.

2 replies

T
Adobe Employee
Tangbo
Adobe Employee
January 3, 2014

Hi Douglas

I have sent mail to the issue owner , he will follow it latter, Sorry for responding it so late.

-Bo

Douglas McCarroll
Douglas McCarrollAuthor
Inspiring
January 3, 2014

Thanks Bo 

J
Justin_as3_rules
Known Participant
December 5, 2013

Hi Douglas, I have not had the ringing that you describe with the app I have published so far. 

All of my sound files are .wav. 

I have a variety of sound, including voice, music and basic sound effects.  I believe all of them are sampled at 44100, but am not sure of this. 

Depending on the sound, at times I have selected raw compression and this works fine.

I am using Flash Pro CS6.

I have tested on all sorts of tablets, including Ipad, Ipad mini and Samsung devices.

Maybe it is the device you are testing on?

Justin

Douglas McCarroll
Douglas McCarrollAuthor
Inspiring
January 1, 2014

Hi Justin,

I somehow missed your reply, even though I'm signed up for email notifications on this thread. I'm not sure what happened - sorry about that - and thanks for replying!

I'm not surprised that you're getting good audio quality using WAV audio. This problem is clearly related to AIR's (Flash's?) handling of MP3 files. While I obviously can't see 'under the hood', my guess is that AIR MP3 decoding uses a 'different' algorithm to decompress the files. I mean, different from virtually everyone else, as none of my other software/devices have any problems with these files. Perhaps Adobe uses an algorithm that is less CPU intensive than most? - perhaps for good reasons?   But, sadly, it makes a fair amount of my voice audio sound like crap.  

> Maybe it is the device you are testing on?

I don't think so - I'm hearing this on multiple devices, both Android and iOS.

If you (or anyone else seeing this post) could take a look at the minimal case example project that I attached to this bug, I'd be grateful. I'm not totally confident that I haven't made some simple coding error. Or perhaps someone could suggest a workaround. I don't think that it will work for me to switch to using WAV files. In my experience WAV audio is about 30 times as large as MP3 versions of the same audio. Perhaps I could use other settings - 8 bit vs. 16 bit, etc. - and reduce the size but it seems unlikely that I'd get my audio down to even a 'mere' 5 times as large - which would still take 5 times as long to download, 5 times as much storage space, etc. My app is all about audio, and lots of it, so I need a compressed format.

Thanks,

Douglas

J
Justin_as3_rules
Known Participant
January 21, 2014

Hi ....quick question......when you import the sound into flash library, what is the sampling rate that you set the sound at......what is the bit rate of the sound itself.....my guess is that the two are close but not identical and not a multiple of each other.....leading to the artifact.

Justin

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