how much difference is expected after data round trip?

[krisfed]

Hello opus community,

I could use a sanity check from somebody with opus expertise...

We are using opus through libsndfile to read/write OggOpus files, and we observed significant differences between data were are trying to write and the data we read back. The absolute differences for individual values can be as large as about 1.

This was specifically for randomly-generated data in the [-1, 1] range. See my post on libsndflie github for more details, such as repro code, data, and pictures.

The more I am looking into it, the more I am inclined to think this is as expected, and randomly generated data is just a bad edge case and not informative to use. We observe much more reasonable differences with something like a pure tone sine wave. But I would really appreciate a confirmation from somebody more familiar with opus codec.

Thank you!