Re: Combining AUHAL input and an AudioConverter
Re: Combining AUHAL input and an AudioConverter
- Subject: Re: Combining AUHAL input and an AudioConverter
- From: William Stewart <email@hidden>
- Date: Tue, 10 May 2005 12:58:22 -0700
On 10/05/2005, at 12:23 PM, Heath Raftery wrote:
On 11/05/2005, at 3:42 AM, Greg Chapman wrote:
On May 10, 2005, at 10:23 AM, Heath Raftery wrote:
What this does is fills out the rest of the ASBD based on the
format.
Alas, it still does not :(
<CONSOLE>
AudioStreamBasicDescription: 0 ch, 48000 Hz,
'Qclp' (0x00000000) 0 bits/channel, 0 bytes/packet, 0 frames/
packet, 0 bytes/frame
</CONSOLE>
I don't think kAudioFormatProperty_FormatInfo will work unless you
fill in the number of channels.
Holy critical observation batman!
<CONSOLE>
AudioStreamBasicDescription: 1 ch, 11025 Hz, 'Qclp' (0x00000000)
0 bits/channel, 35 bytes/packet, 160 frames/packet, 0 bytes/frame
</CONSOLE>
I don't get bytes/frame, bits/channel or flags, but it's certainly
progress! In fact, in the example above, doesn't bytes/frame have
to be 35/160 = 0.21875 bytes/frame? = 1.75bits/frame? Huh?
Nope - the format is packed with multiple frames/packet, there is no
distinct data for you to read/write at the frame (or sample) level -
so both bits/channel and bytes/frame are zero.
Incidentally doubling the number of channels doubles the bytes/
packet only. Different sample rates didn't change anything but
needed to be non-zero.
I think that Qclp only does mono. As for sample rates, it only does
8000 - its a narrow band codec. So, like in my previous email, you
have to set this up as 1 channel, 8000 sample rate - eventually we
get there!
Bill
Taking the code comments' advice, I'll assume the zero fields can
be ignored. Putting all this back into the original application I
was having trouble with that started this thread, I get the same
bad access exception I did originally.
I'll work on it and see if I can get any further, but thank you for
the assistance so far!
Regards,
Heath
--
mailto:email@hidden
tel: +1 408 974 4056
________________________________________________________________________
__
"Much human ingenuity has gone into finding the ultimate Before.
The current state of knowledge can be summarized thus:
In the beginning, there was nothing, which exploded" - Terry Pratchett
________________________________________________________________________
__
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Coreaudio-api mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden