MP3 Hardware Decoding on iPad (was Subscription problem)
MP3 Hardware Decoding on iPad (was Subscription problem)
- Subject: MP3 Hardware Decoding on iPad (was Subscription problem)
- From: "Juan P.Pertierra" <email@hidden>
- Date: Tue, 18 May 2010 11:19:26 -0400
Thank you, I think this answers my question! I've wondered if in the special case of decoding the entire file at once, the software decoder would be faster, just because the hardware decoder might have been designed to work in real-time explicitly. I guess it is possible for the hardware decoder to not provide much advantage over software when decoding the whole file as fast as possible. Another possibility is that my tests with Audio Queue Offline Render were incorrectly setup...I will look at this again.
Sorry again for the multiple posts, for some reason I can't see my own posts to the list, even though I have the option set in my preferences.
Thanks! Juan
Sent from my iPad On May 18, 2010, at 10:53 AM, "Paul Sanders" < email@hidden> wrote:
> It's admittedly a little weird to write a 6 minute
MP3 to PCM directly in memory. That's a lot of memory.
Yes, about 60MB by my calculation. If you need to
directly address your decoded audio, you might consider using a memory-mapped
file (i.e. decode to a file and then map that file into memory). That
way the OS can manage the memory for you, based on your pattern of access and
other demands on the system. I believe the iPad supports
this.
If you're generating some kind of waveform display from
the raw PCM data, there are more efficient ways at low zoom levels.
Paul Sanders.
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