[FFmpeg-devel] [PATCH 2/3] idet improvements: add reset_count feature

[Michael Niedermayer]

On Sun, Nov 02, 2014 at 06:20:06PM -0800, Kevin Mitchell wrote:
> I made the decay multiplication fixed point. I moved all the fixed
> point logic to macros which hopefully makes it easier to read.
> 
> I also removed the total_frames count since it is now likely to become
> inconsistent with the actual classification totals anyway.
> 
> I've gone back to just outputting rounded integers to av_log so as not
> to break scripts of people who are insane enough to try and parse it
> (bash can't handle float).
> 
> I used your suggestion for formatting fixed point decimal values for
> the metadata tags.
>  doc/filters.texi      |    5 +++
>  libavfilter/version.h |    2 -
>  libavfilter/vf_idet.c |   79 ++++++++++++++++++++++++++++++++++----------------
>  libavfilter/vf_idet.h |   15 ++++++++-
>  4 files changed, 74 insertions(+), 27 deletions(-)
> 48d7ffa6bec7940ae0c348fd09308364a69e7cdc  0001-avfilter-vf_idet-add-a-half_life-option-for-statisti.patch
> From 7171918c2f34118679412da72add7b9056e04209 Mon Sep 17 00:00:00 2001
> From: Kevin Mitchell <kevmitch at gmail.com>
> Date: Sun, 2 Nov 2014 04:37:13 -0800
> Subject: [PATCH 1/2] avfilter/vf_idet: add a "half_life" option for statistics
> 
> This can be useful for videos in which the interlacing pattern changes.
> ---
>  doc/filters.texi      |  5 ++++
>  libavfilter/version.h |  2 +-
>  libavfilter/vf_idet.c | 79 +++++++++++++++++++++++++++++++++++----------------
>  libavfilter/vf_idet.h | 15 ++++++++--
>  4 files changed, 74 insertions(+), 27 deletions(-)
> 
> diff --git a/doc/filters.texi b/doc/filters.texi
> index 33f842b..ae08f32 100644
> --- a/doc/filters.texi
> +++ b/doc/filters.texi
> @@ -5625,6 +5625,11 @@ The filter accepts the following options:
>  Set interlacing threshold.
>  @item prog_thres
>  Set progressive threshold.
> + at item half_life
> +Number of frames after which a given frame's contribution to the
> +statistics is halved (i.e., it contributes only 0.5 to it's
> +classification). The default of 0 means that all frames seen are given
> +full weight of 1.0 forever.
>  @end table
>  
>  @section il
> diff --git a/libavfilter/version.h b/libavfilter/version.h
> index 440c587..dab9b45 100644
> --- a/libavfilter/version.h
> +++ b/libavfilter/version.h
> @@ -31,7 +31,7 @@
>  
>  #define LIBAVFILTER_VERSION_MAJOR  5
>  #define LIBAVFILTER_VERSION_MINOR  2
> -#define LIBAVFILTER_VERSION_MICRO 101
> +#define LIBAVFILTER_VERSION_MICRO 102
>  
>  #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
>                                                 LIBAVFILTER_VERSION_MINOR, \
> diff --git a/libavfilter/vf_idet.c b/libavfilter/vf_idet.c
> index 6f99f39..d0b3aa2 100644
> --- a/libavfilter/vf_idet.c
> +++ b/libavfilter/vf_idet.c
> @@ -32,6 +32,7 @@
>  static const AVOption idet_options[] = {
>      { "intl_thres", "set interlacing threshold", OFFSET(interlace_threshold),   AV_OPT_TYPE_FLOAT, {.dbl = 1.04}, -1, FLT_MAX, FLAGS },
>      { "prog_thres", "set progressive threshold", OFFSET(progressive_threshold), AV_OPT_TYPE_FLOAT, {.dbl = 1.5},  -1, FLT_MAX, FLAGS },
> +    { "half_life", "half life of cumulative statistics", OFFSET(half_life),     AV_OPT_TYPE_FLOAT, {.dbl = 0.0},  -1, INT_MAX, FLAGS },
>      { NULL }
>  };
>  
> @@ -48,6 +49,14 @@ static const char *type2str(Type type)
>      return NULL;
>  }
>  
> +static int av_dict_set_fxp(AVDictionary **pm, const char *key, uint64_t value, int decimal_digits,
> +                int flags)
> +{
> +    char valuestr[44];
> +    snprintf(valuestr, sizeof(valuestr), "%"PRId64".%0*"PRId64, FXP_TO_DECIMAL(value, decimal_digits));
...
> +#define FXP_TO_DECIMAL(value,digits) (value) / PRECISION, (digits), (uint64_t) round(( (value) % PRECISION) / (double) (PRECISION / pow(10.0, (digits) )))

thats still using floating point calculations
round(), pow(), and double are not integer based

also it will give incorrect results i think 0.99999 could get printed
as 0.100 when the remainder is rounded up


[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Frequently ignored answer#1 FFmpeg bugs should be sent to our bugtracker. User
questions about the command line tools should be sent to the ffmpeg-user ML.
And questions about how to use libav* should be sent to the libav-user ML.
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