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

Jason Garrett-Glaser jason
Fri Dec 3 00:38:21 CET 2010


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



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