Re: How do you pause, stop and reset an AUFilePlayer in IOS5?
Re: How do you pause, stop and reset an AUFilePlayer in IOS5?
- Subject: Re: How do you pause, stop and reset an AUFilePlayer in IOS5?
- From: Aran Mulholland <email@hidden>
- Date: Wed, 01 Aug 2012 11:51:06 +1000
Is the reason you are calling AUGraphStop because you are getting more
accurate current time stamps from the various AUFilePlayers?
On Wed, Aug 1, 2012 at 12:30 AM, Beleg Da'Bear <email@hidden> wrote:
> There is a quarter of a second, maybe half a second delay on my iphone 4. It
> is not really noticeable unless you know to look for it. I shaved a little
> time off by calling only ConfigureAndInitializeAudioProcessingGraph
> (applicable if you used the MixerHost as a template) instead of the 4 other
> set up routines
>
> From: Aran Mulholland <email@hidden>
> To: Beleg Da'Bear <email@hidden>
> Cc: "email@hidden" <email@hidden>
> Sent: Monday, July 30, 2012 7:25 PM
>
> Subject: Re: How do you pause, stop and reset an AUFilePlayer in IOS5?
>
> Does restarting the AUGraph mean the app is unresponsive when you hit play?
>
> On Tue, Jul 31, 2012 at 7:04 AM, Beleg Da'Bear <email@hidden> wrote:
>> I figured it out. In case you ever run into the same problem, here was my
>> solution
>> 1. On startup, I initialize the AUGraph with an array of file player
>> audio units. I set the play head of each track in the file player audio
>> unit
>> array to zero.
>> 2. On “pause” , first I stop the AuGraph. Then I loop through the
>> array
>> of file player audio units and capture the current playhead position. Each
>> time the pause button is pressed, I make sure I add the new current
>> playhead position to the old playhead position to get its true position.
>> 3. When the user hits play, I re initialize the AuGraph just as if I
>> was coming to the page for the very first time, only I set the playhead to
>> the number I stored when the user hit “pause” instead of telling it to
>> play
>> at the start of the file.
>> 4. If the user clicks stop, I set the stored playhead position to
>> zero
>> and then stop the AuGraph.
>>
>> This may not be the most efficient way to do things, I still think that
>> using kAudioUnitProperty_ScheduleStartTimeStamp to start the multiple file
>> player audio units in a few seconds in the future would work better, but
>> since I could not get that to work and this method is working for me, I
>> will
>> take it. My only issue at this point is that when I pause and then play
>> again, it starts the playhead a second or a second and a half earlier then
>> when I expect it too. But I am sure I will be able to figure out this
>> minor
>> bug when I get back to this project over the weekend.
>> Aran,
>> Robert,
>> Thanks for your pointers as well the link to Doug Wyatt’s code.
>> This was helpful in getting me on the right path
>>
>> From: Beleg Da'Bear <email@hidden>
>> To: Aran Mulholland <email@hidden>
>> Cc: "email@hidden" <email@hidden>
>> Sent: Thursday, July 26, 2012 11:51 AM
>>
>> Subject: Re: How do you pause, stop and reset an AUFilePlayer in IOS5?
>>
>> Yes. My thinking is that, since all my tracks are the same size, I can
>> assign the playback head to the same number that i get from the first
>> track.
>> (my tests have indicated this will work). However there is still the
>> problem
>> scheduling when the playback should begin. Typically I would want the File
>> Player to start right away. I can accomplish this by setting mSampleTime =
>> -1. However since this is all happening in a loop, I want the playback to
>> begin after a slight delay, perhaps 1 second from the current time. Does
>> anyone know what I would need to set mSampleTime to in this case?
>> Code:
>>
>> // tell the file player AU when to start playing (-1 sample time means
>> next
>> render cycle)
>> AudioTimeStamp startTime;
>> memset (&startTime, 0, sizeof(startTime));
>> startTime.mFlags = kAudioTimeStampSampleTimeValid;
>> startTime.mSampleTime = -1;
>> AudioUnitSetProperty(fileUnitArray[mycount],
>> kAudioUnitProperty_ScheduleStartTimeStamp, kAudioUnitScope_Global, 0,
>> &startTime, sizeof(startTime));
>>
>>
>>
>>
>> From: Aran Mulholland <email@hidden>
>> To: Beleg Da'Bear <email@hidden>
>> Cc: Robert Martin <email@hidden>;
>> "email@hidden" <email@hidden>
>> Sent: Tuesday, July 24, 2012 7:43 PM
>> Subject: Re: How do you pause, stop and reset an AUFilePlayer in IOS5?
>>
>> If you knew the host time that you started the region at you could get
>> the host time when you hit pause and work this out without asking the
>> API.
>>
>> On Tue, Jul 24, 2012 at 11:47 PM, Beleg Da'Bear <email@hidden>
>> wrote:
>>> Thanks. after I took out the bits stopping the AuGraph as well as adding
>>> in
>>> a step I skipped (I forgot to do kAudioUnitProperty_ScheduleFilePrime) I
>>> get
>>> the pause play behavior that I am looking for, however as I expected
>>> pausing
>>> and then playing again causes the 8 tracks to get slightly out of synch.
>>> I
>>> suspect that this is happening because I have a for loop that cycles
>>> through
>>> my FilePlayer Audio Unit array to capture the current sample time and
>>> this
>>> must be introducing a slight delay for the time it takes to loop through
>>> all
>>> 8 tracks. Do you know of a way to get the sample time for all 8 files at
>>> the same time?
>>>
>>> From: Aran Mulholland <email@hidden>
>>> To: Beleg Da'Bear <email@hidden>
>>> Cc: Robert Martin <email@hidden>;
>>> "email@hidden" <email@hidden>
>>> Sent: Monday, July 23, 2012 8:15 PM
>>>
>>> Subject: Re: How do you pause, stop and reset an AUFilePlayer in IOS5?
>>>
>>> Don't stop the AUGraph. The time it takes to start is too long. the
>>> AUFilePlayer will just fill the buffer with 0's if it is not playing
>>> and probably sets the "norender" flag as well. This way when you start
>>> the player again it start playing straight away.
>>>
>>>
>>> On Tue, Jul 24, 2012 at 4:52 AM, Beleg Da'Bear <email@hidden>
>>> wrote:
>>>> Upon closer inspection it looks like I am not always getting the value I
>>>> should for the sample frame.
>>>> When I do this the first time:
>>>> AudioTimeStamp ts;
>>>> UInt32 size = sizeof(ts);
>>>> AudioUnitGetProperty(myArrayOfFileUnits[count],
>>>> kAudioUnitProperty_CurrentPlayTime, kAudioUnitScope_Global, 0, &ts,
>>>> &size);
>>>> I get the number I would expect. the second time I hit pause
>>>> ts.mSampleTime
>>>> = -1.
>>>> Any thoughts on why this would be the case?
>>>> As a follow up question, Should I be worried about the time it takes to
>>>> looping through an array of FilePlayer units to get the sampleTime for
>>>> each
>>>> unit? In other words is it possible that I will capture the current play
>>>> head for each track at a slightly different time, thus making them
>>>> misaligned when I hit play again? If this is the case, how would I work
>>>> around that problem?
>>>>
>>>>
>>>> From: Beleg Da'Bear <email@hidden>
>>>> To: Robert Martin <email@hidden>; Aran Mulholland
>>>> <email@hidden>
>>>> Cc: "email@hidden" <email@hidden>
>>>> Sent: Monday, July 23, 2012 2:01 PM
>>>>
>>>> Subject: Re: How do you pause, stop and reset an AUFilePlayer in IOS5?
>>>>
>>>> Thanks. I tried this method out this weekend and I am having trouble
>>>> making
>>>> it work. Should I be stopping and starting the AudioGraph each time?
>>>> Here is my aproch (My code complicates things a little because I am
>>>> trying
>>>> to play/pause 8 files at the same time.)
>>>> If the user presses the play button.
>>>> 1. Loop through the 8 FilePlayer audio units scheduling the start frame
>>>> of
>>>> each unit to 0;
>>>> 2. call AUGraphStart
>>>> If the user presses the pause button.
>>>> 1. Loop through the 8 FilePlayer audio units and get the sample frame of
>>>> the
>>>> curently playing tracks.
>>>> 2. Store this number for later (if the user hits pause a second time add
>>>> the
>>>> new number to the old number, i.e. SampleFrame=SampleFrame +
>>>> ts.mSampleTime;)
>>>> 3. call AudioUnitReset
>>>> 4. Stop the AuGraph
>>>> When the user unpauses the pause button
>>>> 1. Loop through the 8 FilePlayer audio units and set the startFrame to
>>>> the
>>>> number we stored
>>>> 2. call AUGraphStart
>>>> When the user hits stop
>>>> 1. stop the AUGRAPH
>>>> 2. Reset the sampleFrame to zero for all FilePlayer audio units
>>>> The behavior I am seeing is that the music plays fine the first time
>>>> that
>>>> the play button is pressed. Pressing pause or stop stores the value I
>>>> expect
>>>> to see in the startFrame, however pressing play again does nothing. I
>>>> hear
>>>> nothing. The odd thing is that If I press pause and then play realy
>>>> really
>>>> quickly, it works as I want it to, however I think this is because I am
>>>> hitting play because the AUGraph had a chance to really stop. but I am
>>>> not
>>>> sure. Any ideas what I am missing?
>>>>
>>>>
>>>> Thanks.
>>>>
>>>>
>>>> From: Robert Martin <email@hidden>
>>>> To: Aran Mulholland <email@hidden>
>>>> Cc: Beleg Da'Bear <email@hidden>;
>>>> "email@hidden"
>>>> <email@hidden>
>>>> Sent: Thursday, July 19, 2012 1:13 AM
>>>> Subject: Re: How do you pause, stop and reset an AUFilePlayer in IOS5?
>>>>
>>>> It's a bit more complicated than that.
>>>>
>>>> What you'll get from 'getting' kAudioUnitProperty_CurrentPlayTime is the
>>>> -offset- time from when you last set
>>>> kAudioUnitProperty_ScheduledFileRegion.
>>>>
>>>> If you schedule a new region with that time, you won't resume at the
>>>> correct
>>>> place if you pause/resume more than once.
>>>>
>>>> Here is a copy of Doug Wyatt's note on this from 2006, since I no longer
>>>> have the link:
>>>>
>>>> "To change the play position:
>>>>
>>>> [1] obtain the current play position:
>>>> AudioTimeStamp ts;
>>>> UInt32 size = sizeof(ts);
>>>> AudioUnitGetProperty(mFilePlayerAU,
>>>> kAudioUnitProperty_CurrentPlayTime, kAudioUnitScope_Global, 0, &ts,
>>>> &size);
>>>> Float64 sampleFrame = ts.mSampleTime;
>>>>
>>>> Now you know where playback is, relative to the beginning of the
>>>> event timeline that you scheduled. If you scheduled the beginning of
>>>> a file to play at the beginning of the timeline, then the play
>>>> position is the same as the position in the file (except in the case
>>>> of sample rate conversion, which is another wrinkle.....)
>>>>
>>>> [2] stop:
>>>>
>>>> AudioUnitReset(mFilePlayerAU, kAudioUnitScope_Global, 0);
>>>>
>>>> [3] start again. Here you can specify the starting sample offset in
>>>> the file.
>>>>
>>>> For example, to implement pause/resume, you'd obtain the play
>>>> position before pausing, and add that to the position in the file
>>>> where you last started. That would be the playRegion.mStartFrame when
>>>> scheduling the first event when you resume."
>>>>
>>>> Rob
>>>>
>>>>
>>>>
>>>> On Jul 18, 2012, at 7:36 PM, Aran Mulholland <email@hidden>
>>>> wrote:
>>>>
>>>>> You can't pause the AUFilePlayer. What you can do is call something
>>>>> like
>>>>>
>>>>> AudioTimeStamp ts;
>>>>> UInt32 size = sizeof(ts);
>>>>> AudioUnitGetProperty(filePlayerUnit_,
>>>>> kAudioUnitProperty_CurrentPlayTime, kAudioUnitScope_Global, 0, &ts,
>>>>> &size);
>>>>> Float64 sampleFrame = ts.mSampleTime;
>>>>>
>>>>> to get the currently playing sample frame, then call
>>>>>
>>>>> AudioUnitReset(filePlayerUnit_, kAudioUnitScope_Global, 0);
>>>>>
>>>>> To stop it and if you want to resume playback (from pause), schedule a
>>>>> new region with the sample time you had before you called
>>>>> AudioUnitReset. Be nice if it had a pause, but not hard to implement
>>>>> yourself.
>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>
>>
>>
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| References: | |
| | >How do you pause, stop and reset an AUFilePlayer in IOS5? (From: "Beleg Da'Bear" <email@hidden>) |
| | >Re: How do you pause, stop and reset an AUFilePlayer in IOS5? (From: Aran Mulholland <email@hidden>) |
| | >Re: How do you pause, stop and reset an AUFilePlayer in IOS5? (From: Robert Martin <email@hidden>) |
| | >Re: How do you pause, stop and reset an AUFilePlayer in IOS5? (From: "Beleg Da'Bear" <email@hidden>) |
| | >Re: How do you pause, stop and reset an AUFilePlayer in IOS5? (From: "Beleg Da'Bear" <email@hidden>) |
| | >Re: How do you pause, stop and reset an AUFilePlayer in IOS5? (From: Aran Mulholland <email@hidden>) |
| | >Re: How do you pause, stop and reset an AUFilePlayer in IOS5? (From: "Beleg Da'Bear" <email@hidden>) |
| | >Re: How do you pause, stop and reset an AUFilePlayer in IOS5? (From: Aran Mulholland <email@hidden>) |
| | >Re: How do you pause, stop and reset an AUFilePlayer in IOS5? (From: "Beleg Da'Bear" <email@hidden>) |
| | >Re: How do you pause, stop and reset an AUFilePlayer in IOS5? (From: "Beleg Da'Bear" <email@hidden>) |
| | >Re: How do you pause, stop and reset an AUFilePlayer in IOS5? (From: Aran Mulholland <email@hidden>) |
| | >Re: How do you pause, stop and reset an AUFilePlayer in IOS5? (From: "Beleg Da'Bear" <email@hidden>) |