Continuous waveform

[dy]

For large ranges, when a pass width becomes too narrow, the more fruitful strategy would be to render continuous waveform, similar to audacity suggestion.

That can be done when data has integral stats, eg. for each texture row.
Alternatively, we can collect texture data for levels and render multiple textures in result.

* 
|   * 
| * | 
| | |
* * * ...
| * *
* | *
* * |

So we collect a row-stats texture, where every pixel represents 4 level values corresponding to the texture row.
In shader we lerp vertically, to make transition gradual, not sharp levels.