| 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.
Joe
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