PtBi version 5

I just released a new major version of PtBi, with 2 new features.

Dolby Digital 5.1 decoding

PtBi can now decode audio streams transmitted in Dolby Digital 5.1 format. Together with the existing DTS 5.1 decoding, this should now allow for true surround sound from almost any source. I believe that PtBi is the only Blackmagic Intensity capture program with this type of audio support.
This was easier than I expected, at least at first, because the decoding library functions very similarly to the one I used for DTS, but I was stuck for hours without any progress. It turns out that someone thought it would be a good idea to standardize a bitstream format such that it can be either big-endian or little-endian. Ugh.

SMAA integration

In addition to the existing FXAA, PXAA and TPXAA post-processing AA modes PtBi now also supports SMAA1x. SMAA1x has slightly better edge quality and motion stability than FXAA. I’ll look into integrating SMAA with my predication filters at some point in the future.


Also, I plan to release the source code for PtBi soon-ish. I was always reluctant to do this, since some of it is based on code I wrote almost a decade ago which is pretty terrible, but I cleaned it up slightly now. And some parts of it, like how to integrate the AA modes in OpenGL or how to use the various libraries for audio decoding/playback might be useful to someone. Also, it could help people identify and solve problems with AMD cards, which are always very hard for me to test/debug without access to the hardware.

Audio programming and DTS decoding

Since I recently gained the option of connecting digital audio to my capture card, and since some people requested it, I added audio handling to PtBi. This required less effort than I originally anticipated, partly due to the ease of use of the bass audio library. It’s a tiny .dll and quite well documented.

One disappointment was discovering that the Blackmagic Intensity Pro doesn’t handle more than 2 audio channels. However, with some bit fiddling, it’s possible to reconstruct and decode DTS 5.1 encoded audio frames from the left/right channels supplied by the hardware. While this could mean that PtBi now may or may not violate any number of software patents in some countries, I doubt anyone cares.

Since I was getting into this audio stuff, I also added some quick features I could use such as a general audio level boost and stereo to quadrophonic expansion.