Re: writing m4a problems continued
Re: writing m4a problems continued
- Subject: Re: writing m4a problems continued
- From: William Stewart <email@hidden>
- Date: Mon, 20 Jun 2005 11:01:26 -0700
You'll need to set the magic cookie first I think, before you start
writing data - probably should have a better error code for this.
Bill
On 20/06/2005, at 7:06 AM, Simon Liu wrote:
Hi Doug & John,
Did you manage to resolve error 0xFFFFFFF8, or -8, from
AudioFileWritePackets? I am converting 2-ch Float32PCM to AAC, with
filetype of kAudioFileM4AType, and I am also getting this error.
Things seem okay as each invocation of
AudioConverterFillComplexBuffer() returns noErr, and the
AudioStreamPacketDescription is filled out. When invoking
AudioFileWritePackets, I start sequentially from 0. Not sure why -8
error is returned...
I believe my input and output ABSDs and AudioFile are setup correctly
(they work when converting with ExtFileAudio).
Two things which may or may not be relevant are:
- I do not set a magic compression cookie
- I have set AudioConverterFillComplexBuffer()'s AudioBufferList
*outOutputData to: 1 buffer, interleaved, 2 channel. (Aside: It
doesn't make sense to have a non-interleaved buffer list for
compressed packet data, right?)
I've attached some debug output which might help (PR means Packets
Rendered):
AudioConverter 0x280a614 [0x50f460]:
CodecConverter 0x510d80
Input: 2 ch, 44100 Hz, 'lpcm' (0x0000000B) 32-bit big-
endian float
Output: 2 ch, 44100 Hz, 'aac ' (0x00000002) 0 bits/channel, 0
bytes/packet, 1024 frames/packet, 0 bytes/frame
AudioConverterFillComplexBuffer: inputPR = 349184, outputPR = 341,
outputByteSize=127016
AudioFileWrite status = -8
AudioConverterFillComplexBuffer: inputPR = 349184, outputPR = 341,
outputByteSize=126853
AudioFileWrite status = -8
AudioConverterFillComplexBuffer: inputPR = 349184, outputPR = 341,
outputByteSize=126200
AudioFileWrite status = -8
AudioConverterFillComplexBuffer: inputPR = 240640, outputPR = 235,
outputByteSize=88001
AudioFileWrite status = -8
EOF
---
Regards,
Simon
On 5/7/05, john <email@hidden> wrote:
Hi Doug,
It errors at every call to AudioFileWritePackets(). I do start
with packet
0. Also, I have the code setup to increment the
packetWritePosition based on
the number of packets that have been written, like the CAAudioFile
code.
Not sure if this means anything, but the first conversion from
AudioConverterFillComplexBuffer() returns 7 bytes, then
things pick up to 379 (app.) and continue at about that rate. The
error
stays the same, regardless.
Thanks!
-- John
John,
That looks like an error code from the MP4 audio file
component ... hm, a
MP4DataInformationAtom has a nil dataReference atom pointer.
When writing .mp4/.m4a, the component requires that you start with
packet 0
and write packets sequentially from there. What packet number are you
writing when this fails? What packet numbers have you written
previously?
Doug
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