Re: afconvert producing 4K stubs in Leopard, but converting properly in Tiger...Need a hand!
Re: afconvert producing 4K stubs in Leopard, but converting properly in Tiger...Need a hand!
- Subject: Re: afconvert producing 4K stubs in Leopard, but converting properly in Tiger...Need a hand!
- From: Robert Martin <email@hidden>
- Date: Fri, 29 Aug 2008 10:35:57 -0400
Joe, yes! Something is 'off' in those AIFs. Apparently, some of
the .aif files that my app was processing had an 8 byte discrepancy
between their actual size, and their 'reported' size. Under Tiger,
coreAudio just truncated to the actual size and processed without a
hiccup. But under Leopard, if the sizes are not exactly the same, the
length is returned as '0' - which effectively hands you back an empty
converted file.
Bill mentioned that they may change this behaviour in the future.
On Aug 29, 2008, at 9:42 AM, Joe Holt wrote:
A few weeks ago Rob Martin asked about an afconvert encoding problem
he was having. I'm seeing the same problem. Some AIF files generate
empty output files. Rob said that this is changed behavior in
Leopard, that the same audio source files encode fine on Tiger. I
haven't been able to test this as I don't have any Tiger machines
left. It's definitely annoying. Here's what verbose afconvert reports:
$/usr/bin/afconvert -v -f m4af -d 'aac ' -s 3 -u vbrq 64 input.aif
output.m4a
Input file: input.aif, 0 frames
strategy = 3
user property 'qrbv' = 64
Formats:
Input file 2 ch, 48000 Hz, 'lpcm' (0x0000000E) 16-bit big-
endian signed integer
Output file 2 ch, 32000 Hz, 'aac ' (0x00000000) 0 bits/
channel, 0 bytes/packet, 1024 frames/packet, 0 bytes/frame
Stereo
Output client 2 ch, 48000 Hz, 'lpcm' (0x0000000E) 16-bit big-
endian signed integer
AudioConverter 0x814a34 [0x11b520]:
PCMConverter 0x120570
Input: 2 ch, 48000 Hz, 'lpcm' (0x0000000E) 16-bit big-endian
signed integer
Output: 2 ch, 48000 Hz, 'lpcm' (0x0000000C) 16-bit little-
endian signed integer
CodecConverter 0x1205f0
Input: 2 ch, 48000 Hz, 'lpcm' (0x0000000C) 16-bit little-
endian signed integer
Output: 2 ch, 32000 Hz, 'aac ' (0x00000000) 0 bits/channel, 0
bytes/packet, 1024 frames/packet, 0 bytes/frame
Input layout tag: 650002
Output layout tag: 650002
Output file: output.m4a, 0 frames
It's curious that it thinks the input file has 0 frames. That would
explain the empty output file!
The same file run through LAME is encoded to mp3 properly. But it's
interesting that FLAC complains and generates no output file:
$ /usr/bin/flac --best -s -f -o output.flac input.aif
input.aif: ERROR: got partial sample
Makes me think there's something "off" about the AIF file that the
Tiger version of afconvert is able to ignore or work around, but
that Leopard is tripping over.
The AIF file was generated in iTunes from a test mp3. I can't find
any AIF analysis tools so I'm stuck with wondering what's up with
these particular files. Any help would be appreciated. I'm building
a transcoder farm for an audio company with mixed Mac and Linux
servers. I'd rather not downgrade to Tiger.
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