Re: ExtAudioFileWriteAsync- skip on write?
Re: ExtAudioFileWriteAsync- skip on write?
- Subject: Re: ExtAudioFileWriteAsync- skip on write?
- From: Jonathan <email@hidden>
- Date: Thu, 1 Jul 2010 15:13:35 -0700
The strange thing is that with the ExtAudioFileWriteAsync removed, the
playback is fine / no skips.
Once I have the ExtAudioFileWriteAsync line uncommented the audio
skips every so often. Maybe once every minute or so although it's not
a fixed duration when it first skips, nor is it a constant interval.
I don't appear to be receiving any memory warnings or anything. Since
I'm seeing a skip, that would imply that the playback callback isn't
finish in time, right? Or can the render callback that's doing the
ExtAudioFileWriteAsync hold things up (at least in theory)?
On Thu, Jul 1, 2010 at 3:00 PM, Art Gillespie <email@hidden> wrote:
>> Are you calling ExtAudioFileWriteAsync from within
>> the render callback and it works fine?
>
> Yes, though I don't have a 3G handy to test with. (Works fine on 3GS and 4.)
>
>> In other words, I should have
>> to create my own writer thread?
>
> No, there's already an internal thread with ExtAudioFileWriteAsync.
> From the comments at ExtendedAudioFile.h:456
>
> "Writes the provided buffer list to an internal ring buffer and
> notifies an internal thread to perform the write at a later time."
>
> On Thu, Jul 1, 2010 at 2:33 PM, Jonathan <email@hidden> wrote:
>> - Hardware/OS: iPhone 3G (3.1.3)
>> - Yep, I'm calling ExtAudioFileWriteAsync outside the render callback.
>> - ExtAudioFileRef is passed via a struct to the render callback
>>
>> As far as the memory warning goes, I'll have to check that out. I
>> wanted to reply right away, though, to verify something I think your
>> message implies. Are you calling ExtAudioFileWriteAsync from within
>> the render callback and it works fine? In other words, I should have
>> to create my own writer thread?
>>
>> On Thu, Jul 1, 2010 at 2:27 PM, Art Gillespie <email@hidden> wrote:
>>> I'm not seeing this here.
>>>
>>> * What hardware/OS version are you experiencing this with?
>>> * Are you calling ExtAudioFileWriteAsync once *outside* the render
>>> callback with 0 frames and NULL buffers to prime the internal ring
>>> buffer?
>>> * How are you synchronizing access to the ExtAudioFileRef?
>>> * Do you get a memory warning at any point during the writing?
>>>
>>> Best,
>>>
>>> Art
>>>
>>> On Thu, Jul 1, 2010 at 9:57 AM, Jonathan <email@hidden> wrote:
>>>> Hey guys,
>>>>
>>>> I'm still having an issue with ExtAudioFileWriteAsync causing skipping
>>>> periodically on an iPhone. Isn't ExtAudioFileWriteAsync supposed to
>>>> handle buffering, etc? I'm sure that the actual writes could cause
>>>> some blocking, so I did move the function out of the render notify
>>>> callback and into a writer thread, but the audio still skips every
>>>> minute or so (presumably when the data is actually write to disk).
>>>
>>
>
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