amadeus inserts silence at end when compressing

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mattn
Posts: 8
Joined: Tue Dec 02, 2008 11:40 pm

amadeus inserts silence at end when compressing

Post by mattn »

Start with an uncompressed AIFF where the sound goes right to the end (no silence at all at end). Open it with Amadeus and save as m4a (AAC). Now close the file and open the m4a. You will see a silence appended to the end of the file.

Is this a bug or is it an inevitable consequence of the compression process?

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Martin Hairer
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amadeus inserts silence at end when compressing

Post by Martin Hairer »

Start with an uncompressed AIFF where the sound goes right to the end (no silence at all at end). Open it with Amadeus and save as m4a (AAC). Now close the file and open the m4a. You will see a silence appended to the end of the file.

Is this a bug or is it an inevitable consequence of the compression process?
I managed to reproduce this. At this stage, it looks like a bug in the function that decodes the m4a file. (The decoded file is indeed slightly longer than the original, with the remainder filled with silence.) I am rather confident that the file itself is OK, i.e. the encoder works as expected since the same glitch appears if I use iTunes for the encoding.

I haven't yet managed to decide whether the bug is in Apple's file reading API or whether it is my fault for using the API incorrectly. Regards,

Martin

HairerSoft
http://www.hairersoft.com/


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