Bugs item #1700821, was opened at 2007-04-14 18:07 Message generated for change (Comment added) made by rhettinger You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=105470&aid=1700821&group_id=5470
Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. >Category: Documentation Group: None Status: Open >Resolution: Accepted Priority: 5 Private: No Submitted By: ncryptor (ncryptor) >Assigned to: Raymond Hettinger (rhettinger) Summary: audioop module - request to add a note Initial Comment: The audioop function lin2lin converts sample sizes of linear pcm fragments. However, when converting to 8-bit, there is a pitfall (that wasted for me a few hours). In some audio formats, such as .WAV files, 16 and 32 bit samples are signed, but 8 bit samples are unsigned. So when converting from 2 to 1 byte wide samples, you need to also add 128 to the result. Example code: new_frames = audioop.lin2lin(frames, old_width, new_width) if 1 == new_width: new_frames = audioop.bias(new_frames, 1, 128) the same, in reverse, has to be applied when converting from 8 to 16 or 32 bit width samples. This wasted so much time for me and is hardly documented. ---------------------------------------------------------------------- >Comment By: Raymond Hettinger (rhettinger) Date: 2007-04-19 01:45 Message: Logged In: YES user_id=80475 Originator: NO I will add a note. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=105470&aid=1700821&group_id=5470 _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
