Why are you using opus not eac3

Hey, it's all quite simple. The original E-AC3 5.1 640kbps audio stream in Netflix sources is ~120MB in size, and transcoding to Opus 128kbps after downmixing to stereo reduces the size to ~20MB with minimal discernable quality losses.

You are free to disagree with that last statement, but in this case I hardly understand why you'd get my release to begin with since the video quality loss is much more important.

You will not see me reencode clearly lossy audio (128-192kbps) any lower, because there's little benefits to that. The idea that lossy audio should never be reencoded under no circumstances is dumb. You are always reencoding from a lossy video (unless you got access to masters? Personally I don't.) but the difference is that the potential for compression is usually much higher. It's rarely the case for audio because most online services only serve already heavily compressed audio. Netflix's highest tier surround streams have quite a high bitrate, with a high potential for further compression down the line.

As you may know, 128kbps Opus is transparent in most cases (even more so when it's an audio track and not actual music). You may discern a quality difference with great audio gear or in rare, well-documented, edge cases, however the audio quality remains much higher than the video quality, even compared to Netflix's own video stream I'd argue, so let alone mine.

All in all, this choice was driven by the fact reencoding E-AC3 5.1 640kbps -> Opus 2.0 128kbps saves more than 2GB in the release total size, which results in almost a 50% size reduction. As for the downmixing, I don't expect many of the users that download my weekly releases to have surround sound systems.

If you don't like any of this, I invite you to get another release that better suits your needs.