I am trying to get my head round this...

Suppose a net radio station broadcasts a music stream in wma at 64 kbps. I capture it on my PC, using the analogue soundcard by recording the "Stereo Mix" (aka "What you Hear") input - as a lossless WAV file in a format for mastering to AudioCD (16bit/stereo/44.1KHz). Then for long-term storage, I save the recording as a FLAC file.

If, instead, I *COMPRESSED* the recorded WAVE file (or the FLAC file derived from it) and saved it as a WMA at 64 kbps - would the resultant audio file be of the *SAME QUALITY* as the original broadcast music stream?

Or would I get the same degradation as would occur by writing a compressed audio file to CD and then re-ripping at the same compression level (the technique often quoted by inexperts to "get-round" DRM issues on music downloads)?

Thanks

You would get the similar(*) degradation as if you had written a compressed audio file to CD and re-ripped at the same compression level.

(*)Most likely worse since you're also re-sampling.

I haven't done any tests myself, and I haven't read about any ABX tests where a file was re-encoded with the same format and bitrate. So, the following is just conceptual & theoretical...

Re-compression - With lossy compression, data is throw-away every time you compress. Information is lost when the file is compressed to 64kbps. This information is truly lost and it is not recovered when the file is de-compressed. More information is lost when it's compressed the 2nd time. On the other hand, it's smart lossy-compression, and most of the information retained during the first compression will again be retained during the 2nd compression (assuming the same bitrate). For the best-possible results, you can use a higher bitrate for the 2nd compression, or you can use a lossless format.

Streaming Capture - This is digitally lossless. (The losses have already occurred during compression.) However, it's a digital-to-analog-to-digital process, and you can get some noise and distortion from the analog circuitry in the sound card. You can avoid the analog step by using software like Total Recorder which has a virtual soundcard. There may be software that can directly capture the streaming WMA as-is, but I've never looked for it.

Thanks both for this expert analysis. I think it's clearer in my head now.

Actually I have made use of some of that other software to capture the WMA files directly; so my storage of these incurs no further loss of quality. They sound the same/no worse than they did when I listen to the audio streamed over the internet. I will probably store them on an 8GB flash-MP3 player for convenient playback when I want to re-listen.