ExtAudioFile seeking bug in m4a files?
ExtAudioFile seeking bug in m4a files?
- Subject: ExtAudioFile seeking bug in m4a files?
- From: "Stephen F. Booth" <email@hidden>
- Date: Sat, 5 Dec 2009 14:27:38 -0800
I've run in to what I think is a bug in ExtAudioFile when seeking in
m4a files. Essentially, after seeking to a frame ExtAudioFileTell()
indicates the incorrect frame (off by the number of priming frames as
elucidated by Doug Wyatt earlier this month) and subsequent calls to
ExtAudioFileRead() followed by ExtAudioFileTell() give even stranger
results:
2009-12-05 14:14:45.958 EAFBug[349:a0f] Tell after opening: -2112
2009-12-05 14:14:45.960 EAFBug[349:a0f] Tell after reading 2048 frames: -64
2009-12-05 14:14:45.960 EAFBug[349:a0f] Tell after reading 2048 frames: 1984
2009-12-05 14:14:45.960 EAFBug[349:a0f] Tell after reading 2048 frames: 4032
2009-12-05 14:14:45.960 EAFBug[349:a0f] Tell after reading 2048 frames: 6080
2009-12-05 14:14:45.960 EAFBug[349:a0f] Tell after reading 2048 frames: 8128
2009-12-05 14:14:45.961 EAFBug[349:a0f] Tell after reading 2048 frames: 10176
2009-12-05 14:14:45.961 EAFBug[349:a0f] Tell after reading 2048 frames: 12224
2009-12-05 14:14:45.961 EAFBug[349:a0f] Tell after reading 2048 frames: 14272
2009-12-05 14:14:45.961 EAFBug[349:a0f] Tell after reading 2048 frames: 16320
2009-12-05 14:14:45.961 EAFBug[349:a0f] Tell after reading 2048 frames: 18368
2009-12-05 14:14:45.962 EAFBug[349:a0f] Tell after seeking to 220500: 218388
2009-12-05 14:14:45.977 EAFBug[349:a0f] Tell after reading 2048 frames: 222888
2009-12-05 14:14:45.977 EAFBug[349:a0f] Tell after reading 2048 frames: 224936
2009-12-05 14:14:45.977 EAFBug[349:a0f] Tell after reading 2048 frames: 226984
2009-12-05 14:14:45.977 EAFBug[349:a0f] Tell after reading 2048 frames: 229032
2009-12-05 14:14:45.978 EAFBug[349:a0f] Tell after reading 2048 frames: 231080
2009-12-05 14:14:45.978 EAFBug[349:a0f] Tell after reading 2048 frames: 233128
2009-12-05 14:14:45.978 EAFBug[349:a0f] Tell after reading 2048 frames: 235176
2009-12-05 14:14:45.978 EAFBug[349:a0f] Tell after reading 2048 frames: 237224
2009-12-05 14:14:45.979 EAFBug[349:a0f] Tell after reading 2048 frames: 239272
2009-12-05 14:14:45.979 EAFBug[349:a0f] Tell after reading 2048 frames: 241320
I have not yet checked to see if the frames returned immediately after
a seek are the correct ones.
For comparison, here is the same code run on an AIFF file:
2009-12-05 14:14:55.526 EAFBug[349:a0f] Tell after opening: 0
2009-12-05 14:14:55.527 EAFBug[349:a0f] Tell after reading 2048 frames: 2048
2009-12-05 14:14:55.527 EAFBug[349:a0f] Tell after reading 2048 frames: 4096
2009-12-05 14:14:55.527 EAFBug[349:a0f] Tell after reading 2048 frames: 6144
2009-12-05 14:14:55.528 EAFBug[349:a0f] Tell after reading 2048 frames: 8192
2009-12-05 14:14:55.528 EAFBug[349:a0f] Tell after reading 2048 frames: 10240
2009-12-05 14:14:55.528 EAFBug[349:a0f] Tell after reading 2048 frames: 12288
2009-12-05 14:14:55.528 EAFBug[349:a0f] Tell after reading 2048 frames: 14336
2009-12-05 14:14:55.528 EAFBug[349:a0f] Tell after reading 2048 frames: 16384
2009-12-05 14:14:55.529 EAFBug[349:a0f] Tell after reading 2048 frames: 18432
2009-12-05 14:14:55.529 EAFBug[349:a0f] Tell after reading 2048 frames: 20480
2009-12-05 14:14:55.529 EAFBug[349:a0f] Tell after seeking to 220500: 220500
2009-12-05 14:14:55.536 EAFBug[349:a0f] Tell after reading 2048 frames: 222548
2009-12-05 14:14:55.536 EAFBug[349:a0f] Tell after reading 2048 frames: 224596
2009-12-05 14:14:55.536 EAFBug[349:a0f] Tell after reading 2048 frames: 226644
2009-12-05 14:14:55.537 EAFBug[349:a0f] Tell after reading 2048 frames: 228692
2009-12-05 14:14:55.537 EAFBug[349:a0f] Tell after reading 2048 frames: 230740
2009-12-05 14:14:55.537 EAFBug[349:a0f] Tell after reading 2048 frames: 232788
2009-12-05 14:14:55.537 EAFBug[349:a0f] Tell after reading 2048 frames: 234836
2009-12-05 14:14:55.537 EAFBug[349:a0f] Tell after reading 2048 frames: 236884
2009-12-05 14:14:55.537 EAFBug[349:a0f] Tell after reading 2048 frames: 238932
2009-12-05 14:14:55.538 EAFBug[349:a0f] Tell after reading 2048 frames: 240980
I'm happy to post my code, but I wasn't sure if this is a known issue
or if I am doing something wrong.
I'm running 10.6.2 on a MacBook Pro.
Stephen
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