Possibly getting a better audio download by mixing parts of 2 different codecs?

2024-12-24 07:13:59

Could it be possible to combine 2 codecs to get a slightly more original audio file?
For example, for YouTube, the 251 codec id is a VBR ~115kbps Opus codec, sometimes tops out around 160kbps.
The 140 codec id is a sort of CBR 140kbps AAC stream. which also has a 16khz cut.

To my ears the AAC has barely a slight improvement in the low end reproduction (might also just be an artifact). But I'm wondering if it's possible to combine the best parts of each codec, since each of them is going to spread the bitrate differently over different parts of the audio spectrum.
So in the simplest concept idea, maybe you combine the audio data from 0 to 10khz of the AAC stream, and 10-20khz of the OPUS stream.

Re: Possibly getting a better audio download by mixing parts of 2 different codecs?

Reply #1 – 2024-12-24 20:17:56

in general it's going to be really tough to know which parts are "best" without knowing the original (but if it was known, could just take the original, ofc)

> maybe you combine the audio data from 0 to 10khz of the AAC stream, and 10-20khz of the OPUS stream

if they can be perfectly time-aligned, this should be doable by using linear-phase lowpass/highpass filters and then summing them
I wouldn't bother personally, but if it's something exceptional without any other source available anywhere, then maybe taking a backup in both formats is a good idea