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Comment by bawolff | Hacker News Reader

Is this really that new? Its basically just using 2 codecs as a hack to get around the fact that hardware is hard to change and thus hard to make improvements to. So instead use one hardware implemented codec that is fixed, and a software one that can be more easily improved.

Surely someone has done that before?

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I am doing something similar, just for the sake of it, on the PlayStation 1 of all things: a custom video codec that takes advantage of the console's hardware MJPEG decoder, but replaces the software side of the stock codec (normally in charge of decompressing the Huffman encoded bitstream into run-length tuples, which are then fed into the decoder) with a slightly more efficient compression scheme.

I'm also trying to leverage the GPU to post-process decoded blocks by e.g. blending them with the previous frame, on hardware that was never meant to support p-frames in the first place. The whole project is still in its early stages though, so there is nothing I can show off (yet).

There are several digital encoding schemes that add enhancement layers on top of an older, established base layer. It's a key concept of backwards compatibility. Not including cases where additional channels or domains of information are added (e.g. surround sound, 3D video), and only looking at cases where the perceptual quality of the existing channels or domains is improved (e.g. HDR, resolution), here are some examples:

* Progressive JPEG (1992)

* Spectral Band Replication (2001) in aacPlus -> HE-AACv1 (2003), mp3PRO (2001), WMA 10 Pro (2006)

* JPEG XT (2015) - enhancements on top of 1992 JPEG.

* Scalable Video Coding (2004? 2007?) (search for "SVC Annex G")

(Keep in mind that software patents aren't about ideas, but specific techniques being used together to achieve an effect, so this isn't intended to be a list of prior art, but rather a list of the same concept being used elsewhere.)

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