[FFmpeg-devel] [PATCH] Add negate filter.

[Jason Garrett-Glaser]

On Thu, Dec 2, 2010 at 3:38 PM, Jason Garrett-Glaser <jason at x264.com> wrote:
> On Thu, Dec 2, 2010 at 3:08 PM, Michael Niedermayer <michaelni at gmx.at> wrote:
>> On Thu, Dec 02, 2010 at 11:18:44PM +0100, Stefano Sabatini wrote:
>>> On date Thursday 2010-12-02 22:55:24 +0100, Michael Niedermayer encoded:
>>> > On Thu, Dec 02, 2010 at 08:45:24PM +0100, Stefano Sabatini wrote:
>>> > > On date Wednesday 2010-12-01 20:57:19 +0100, Stefano Sabatini encoded:
>>> > > > On date Wednesday 2010-12-01 03:25:47 +0100, Michael Niedermayer encoded:
>>> > > > > On Tue, Nov 30, 2010 at 11:22:43PM +0100, Stefano Sabatini wrote:
>>> > > > > > > From 3c16bf49c0f9f4c3c72d9eea49ae35a47d58d961 Mon Sep 17 00:00:00 2001
>>> > > > > > > From: Stefano Sabatini <stefano.sabatini-lala at poste.it>
>>> > > > > > > Date: Fri, 26 Nov 2010 17:31:11 +0100
>>> > > > > > > Subject: [PATCH] Add negate filter.
>>> > > > > > >
>>> > > > > > > Ported from the libavfilter-soc repo with per-component negation
>>> > > > > > > addition.
>>> > > > > > > ---
>>> > > > > > > ?doc/filters.texi ? ? ? ? | ? 22 ++++++
>>> > > > > > > ?libavfilter/Makefile ? ? | ? ?1 +
>>> > > > > > > ?libavfilter/allfilters.c | ? ?1 +
>>> > > > > > > ?libavfilter/vf_negate.c ?| ?184 ++++++++++++++++++++++++++++++++++++++++++++++
>>> > > > > > > ?4 files changed, 208 insertions(+), 0 deletions(-)
>>> > > > > > > ?create mode 100644 libavfilter/vf_negate.c
>>> > > > > >
>>> > > > > > I'll apply in three days unless objections.
>>> > > > >
>>> > > > > is it faster than using a LUT ?
>>> > > >
>>> > > > 32246490 dezicycles in nolut, 1 runs, 0 skips
>>> > > > 27420150 dezicycles in nolut, 2 runs, 0 skips
>>> > > > 29323650 dezicycles in nolut, 4 runs, 0 skips
>>> > > > 36039801 dezicycles in nolut, 8 runs, 0 skips
>>> > > > 34124634 dezicycles in nolut, 16 runs, 0 skips
>>> > > > 39557091 dezicycles in nolut, 32 runs, 0 skips
>>> > > > 37006964 dezicycles in nolut, 64 runs, 0 skips
>>> > > > 37271243 dezicycles in nolut, 128 runs, 0 skips
>>> > > > 36437873 dezicycles in nolut, 256 runs, 0 skips
>>> > > > 37591370 dezicycles in nolut, 512 runs, 0 skips
>>> > > > 37119779 dezicycles in nolut, 1024 runs, 0 skips
>>> > > > 37390082 dezicycles in nolut, 2048 runs, 0 skips
>>> > > >
>>> > > > 22483590 dezicycles in lut, 1 runs, 0 skips
>>> > > > 16486965 dezicycles in lut, 2 runs, 0 skips
>>> > > > 14703345 dezicycles in lut, 4 runs, 0 skips
>>> > > > 13340126 dezicycles in lut, 8 runs, 0 skips
>>> > > > 14286336 dezicycles in lut, 16 runs, 0 skips
>>> > > > 17345394 dezicycles in lut, 32 runs, 0 skips
>>> > > > 18178503 dezicycles in lut, 64 runs, 0 skips
>>> > > > 18047690 dezicycles in lut, 128 runs, 0 skips
>>> > > > 18159589 dezicycles in lut, 256 runs, 0 skips
>>> > > > 17833263 dezicycles in lut, 512 runs, 0 skips
>>> > > > 17624724 dezicycles in lut, 1024 runs, 0 skips
>>> > > > 17303343 dezicycles in lut, 2048 runs, 0 skips
>>> > > >
>>> > > > Updated (with some simplifications).
>>> > > [...]
>>> > >
>>> > > I'll apply in few days if there are no more comments.
>>> >
>>> > There should be a vf_lut.c that does generic LUT based filtering and vf_negate
>>> > should use that filter
>>>
>>> Do you mean apply_lut in libmpcodecs/vf_eq2.c? Why not to implement
>>> some lut in libmpcodecs/vf_geq.c?
>>
>> We need a generic LUT filter, aka specify LUT entries and filter each pixel
>>
>> We need a generic expression filter this is not implementable as LUT as the
>> filter can use any pixels from the input frame not just a 8bit sample but
>> like several megabytes. 2^(2^20) is too big for a LUT
>
> See mt_lut for a good existing implementation (in Avisynth Masktools).
> ?They have both a 1D and 2D LUT (obviously not a 3D one, for the
> reason you mentioned).
>
> Though, to be fair, for complex expressions, a 3D LUT might still be
> better than an expression filter.
>
> Jason
>

Also, you can interpolate a LUT, so it doesn't have to be a full 2^24 entries.

Jason