Minor Issue on libopus 1.3-rc default framesize adjustment
Hi, I couldn't post on the IRC for some reason, that's why I want to post it here. On the libopus 1.3-rc (release candidate), I found it best to change the Framesize setting to 40. In my case I could increase bitrate from 48kbps to 51kbps, where artifacts are hardly heard, while keeping the same file size. These 3 extra bits, may seem little, but they're the difference between noticeable artifacts at 48kbps (in the stereo spectrum) to nearly fully transparent at 51kbps; all the while keeping the same file size.
Audio quality overall improved slightly thanks to this setting. Setting it larger or smaller, did not increase quality or decrease filesize. With that I just want to say that in my opinion, the newer release candidate, runs better with Framesize 40. It would be nice to further be able to finetune this (between the ranges of 20-60) to see where the exact best setting is located. The best framesize setting, could be 30, or it could be 45, without the ability to tune it any other than 20, 40, or 60, I wouldn't know... Not sure if Opus can support such a feature?
Just like CPU complexity is by default set to 10, I think framesize should be set to 40 by default, on the RC candidate (1.3).
Aside from allowing a 6% higher bitrate, while keeping the same file size, it also allows for going much lower in bitrate before capping off the high frequencies. For instance, For stereo music, I can go as low as 24kbps at almost 48kHz (I think it's capped to 32, but it's mostly inaudible); and for mono I can go as low as 12kbps, before the high frequencies are cut. Using Framebuffer 20 or 60, has higher tresholds.