Hi!

> From: [EMAIL PROTECTED]
> 
> To fulfill my need to tweak every knob, I made a trivial patch to

        Based on the past couple days of encoding the one knob I really
        really want to tweak is the selecting blurring one - high motion
        scenes could do with a bit of selective blurring but only the 
        encoder knows when that's needed...

> mpeg2enc.cc to allow the amount by which the quantization for
> high-frequency components is increased to be specified on the command
> line.  I couldn't seem to get optional arguments to work with getopt,
> so I resorted to adding --hf-boost|-k, which takes integers from
> 0-512, with 384 the default (as in the current code).  0 is the same

        Hmmm, the option name is confusing - it sounds as if the HF content
        is being boosted (which would increase the bitrate rather quickly
        I'd think) rather than the quantization of the HF.

        Might I suggest "--increase-hf-q" instead?  Or something that 
        has "q" in it at least?

> high-frequency quantization.  I didn't know what the actual high end
> should be, maybe 512 is too limiting.

        If 384 was the default before then perhaps 512 is a bit limiting -
        you're already most of the way to the limit.   What do your tests
        show - any difference between 384 (the default) and 512 ( the new
        max)?   I wonder what 768 would look like ;)

> This might be useful for those that want some extra bitrate reduction
> but find that the current level results in unacceptable artifacts.  I

        I gotta get me a new TV then - I haven't seen artifacts, or rather
        the ones I do see are the "shades of grey" problem which my feeble
        attempt made worse in most cases (as it turns out using the
        yuvmedianfilter on the chroma only is almost as good as y4mblackfix
        was).

> find the difference between 0 and 512 to be very subtle in most cases,
> but the bit rate difference is often not subtle at all.

        Indeed not!   Or rather I should say the difference in bitrate between 
        0 and 384 is not subtle at all - it made *all* the difference in the
        world trying to get a 118min movie onto a single disc.  Without  -N
        the average bitrate was just too high, with it the average came in
        around 4700 and fit quite nicely.

> I'm not necessarily suggesting this go into CVS or anything, but just
> thought I'd share (this email took longer to write than the patch).

        It's Andrew's "baby" so as soon as he comes un-knackered from Real
        Work we'll see what he thinks ;)

        Cheers,
        Steven Schultz


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