New submission from MosesofEgypt <mosesbobadi...@gmail.com>: --- Issue --- audioop.adpcm2lin and audioop.lin2adpcm currently treat the high 4 bits of each byte as the first code and the low 4 as the second code. In practice this is often the opposite. http://www.drdobbs.com/database/algorithm-alley/184410326 https://wiki.multimedia.cx/index.php/Microsoft_IMA_ADPCM
--- Steps to reproduce --- Run the attached script to decompress the attached wav to two different 16bit signed pcm wav files. The "GOOD" one had the nibbles of each code swapped before being decoded, while the "BAD" one didnt. --- Suggested fix --- I propose an additional optional boolean parameter to these functions to specify which nibble is the first code and which is the second. NOTE: I haven't compiled my changes to test as I do not know how to set up a cpython build environment. This commit is more intended to show how to implement the fix. https://github.com/MosesofEgypt/cpython/commit/4a5ca65833ec79857f065546ae0d90661ce26f5f ---------- files: adpcm_test.zip messages: 306063 nosy: MosesofEgypt priority: normal severity: normal status: open title: Allow specifying code packing order in audioop adpcm functions type: enhancement versions: Python 3.4, Python 3.5, Python 3.6, Python 3.7, Python 3.8 Added file: https://bugs.python.org/file47258/adpcm_test.zip _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue32004> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
