On Fri, May 29, 2009 at 12:41:10PM -0400, Alex Converse wrote: > On Fri, May 29, 2009 at 12:00 AM, Kostya <kostya.shish...@gmail.com> wrote: > > > > On Thu, May 28, 2009 at 05:53:51PM -0400, Alex Converse wrote: > > > Hi, > > > > > > This patch seems to vastly improve HCB selection in the AAC encoder. > > > The screenshot demonstrates its results. (out-1 is before, out-2 is > > > after, chunk is input) > > > > > > Regards, > > > Alex Converse > > > > I believe it does, the question is why? > > I see two changes - in codebook selection (which does the same thing > > on the first glance) and in its traversal. > > The first chunk of the new code iterates over each stage (swb) and > figures out the total cost to get to each state (hcb) by staying in > that state from the previous stage and by transitioning to that state > from the lowest cost state of the previous stage. > > The old code seems to also iterate over each chunk and figures out the > cost to get to each state (hcb) by staying in that state from the > previous stage then it seems to compute, as it's alternate cost, the > cost of navigating to that state in the previous stage plus the cost > of the lowest cost stage of *this state* (including run increase > penalties but not the navigation cost). If that cost is lower, we mark > it as a transition from the lowest cost state this stage. That second > quantity and how it is handled doesn't seem to make a lot of sense.
Indeed, so that was my error. > > Does the second part fix some bug, simple ineffectiveness or simply > > needed for changed codebook selection scheme? > > > > The second part simply walks us back to the proper place to look at > the previous state on a run > 1. It's hard to evaluate on it's own > since the old code it interfaced with doesn't make a lot of sense. Apply as single patch then. > [...] > > --Alex _______________________________________________ FFmpeg-soc mailing list FFmpeg-soc@mplayerhq.hu https://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-soc
