Re: WMA on the iPhone
Re: WMA on the iPhone
- Subject: Re: WMA on the iPhone
- From: Marco Papa <email@hidden>
- Date: Sun, 11 Jan 2009 15:29:55 -0800
Date: Sat, 10 Jan 2009 16:09:43 -0500
From: Norman Franke Lists <email@hidden>
Subject: Re: WMA on the iPhone
To: CoreAudio API <email@hidden>
Message-ID: <email@hidden">email@hidden>
Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes
I'd guess the issue is that the iPhone may not have enough CPU to
decode WMA and do anything else. Transcoding, if possible, would allow
the audio hardware to do the heavy lifting.
-Norman Franke
There's plenty of CPU to decode on the iPhone. I know of at least three other products on the AppStore that use the FFMPEG library to decode WMA, and encode on-the-fly into another format (likely Linear PCM) and feed the resulting audio to the iPhone audio queues. This is with WMA streams as high as 192 Kbps, which is plenty for good sound.
-- Marco
On Jan 10, 2009, at 4:35 AM, Brian Willoughby wrote:
> MP3 was not designed as an interim memory storage format. It's
> totally inappropriate to convert to MP3 as a bridge between other
> technologies. The inventors of MP3 would shudder. Even if you
> don't care about quality, you'll probably find it harder to support
> MP3 playback, and all the encoding and decoding would surely sap the
> CPU.
>
> What's wrong with convert-on-the-fly to Linear PCM? You could even
> use the 8.24 native format for the iPhone, or whatever the exact
> format is. That would entail very little CPU overhead. With a
> circular buffer, it would not even require significantly more memory.
>
> Brian Willoughby
> Sound Consulting
>
>
> On Jan 10, 2009, at 00:05, Marco Papa wrote:
>> My app plays MP3 and AAC streams using Audio Queue Services. I
>> would like to add streaming WMA (Windows Media Audio) . One
>> suggestion that I have had is to use the version of ffmpeg which
>> has been ported to the iPhone, let it parse the streamed audio
>> (currently I do it with Audio File Stream Services) and convert on-
>> the-fly from WMA into MP3 and feed the resulting MP3 stream to
>> Audio Queue services. Would this work? Any other ideas?
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