Re: Playing multiple MP3 songs simultaneously on iPhone
Re: Playing multiple MP3 songs simultaneously on iPhone
- Subject: Re: Playing multiple MP3 songs simultaneously on iPhone
- From: Marion Di Giacomo <email@hidden>
- Date: Wed, 10 Feb 2010 16:30:32 +0100
Hello !
I tried to use AudioQueue on the simulator (I can't test on a device
yet). Do you know if the behaviour is the same on the simulator and on
the device ? Is there only one MP3 hardware decoder running on the
simulator ? Since I used an example and I am a really newbie, I don't
know if I really understood the code I used.
When I tried on the simulator, each track seems to play correctly. I
create one AudioQueue per track, and run them at same time. But I
don't know if it can prove that they will be synchronous.
2010/2/10 William Stewart <email@hidden>:
> On Feb 9, 2010, at 7:09 PM, Steven Winston wrote:
>
> Just for the sake of being pedantic:
> You can use a grand total of 1 HW pathed MP3 at a time.
>
> yes.
>
> That is to say the HW supports having one and only one MP3 running through
> it at once.
>
> yes
>
> You can use the software decoders as many as the system can support at a
> time without the limitation of the CPU running out of resources.
>
> That is also correct.
>
> In practice on the iPhone I've gotten up to 5 simultanous decoding sessions
> to work where 1 is hardware the other 4 are software.
>
> Depends on the model of iPhone. This is probably about right for the 3G (and
> the original model), but for the 3GS I would expect more than this. For the
> iPod touch, the second generation should be better than the numbers you
> quote above as well
> This is also why I proposed the idea of AAC; it is a more efficient codec,
> so you can do more and have more flexibility with it.
>
> Something else that you *might* be able to do (I've not tested this), is to
> utilize 1 MP3 HW decoder and 1 other HW decoder that isn't for MP3 at the
> same time.
>
> nope - the model we provide is for one use case for the hw at a given time
> regardless of format (it is the same h/w block being used)
>
> So for example you might have one AAC and one MP3 HW decoders at the same
> time.
>
> Thanks,
> Steve
>
> On Tue, Feb 9, 2010 at 6:09 PM, William Stewart <email@hidden> wrote:
>>
>> audio queue is fine.
>>
>> it will use a software MP3 decoder (see various documentation on that). If
>> you can use AAC it is better (the decoder is more efficient than MP3, and
>> you can also make the files smaller for the same quality)
>>
>> On Feb 9, 2010, at 6:44 AM, Marion Di Giacomo wrote:
>>
>>> Hello !
>>>
>>> I would like to do a mixing table on iPhone. I have the different
>>> tracks of one song and I want to play them on iPhone simultaneously.
>>> These songs are MP3 files, I want to be able to play up to 15 tracks
>>> simultaneously, and changing volume, muting some tracks, navigating in
>>> the total song, etc.
>>>
>>> Apple MultichannelMixer example seems to do exactly what I want, but
>>> MP3 files need to be decompressed before being played. They seem to be
>>> decompressed to CAF files, and take a lot of space in memory (my songs
>>> can last up to 5 minutes).
>>>
>>> I tried SpeakHere example too, and use AudioQueue. I tried it with
>>> playing 6 AudioQueues simultaneously. It seems to work on the
>>> simulator, but I don't know if it will work on the device, and if it
>>> can do what I want.
>>>
>>> I don't know what is the best way to do this... Can anybody help me ?
>>>
>>> sui
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>
--
Marion Di Giacomo
Diplômée du Génie Informatique à l'UTC (Université de Technologie de Compiègne)
Filière ICSI (Ingénierie des Connaissances et des Supports d'Information)
Mineur TCN (Technologies Culturelles Numériques)
http://mariondigiacomo.fr.st
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