On date Tuesday 2015-11-10 00:25:30 +0100, Marton Balint encoded:
> This option can be used to select useful frames from an ffconcat file which is
> using inpoints and outpoints but where the source files are not intra frame
> only.
>
> Signed-off-by: Marton Balint <c...@passwd.hu>
> ---
> doc/filters.texi | 17 +++++++++++++++++
> libavfilter/f_select.c | 27 +++++++++++++++++++++++++++
> 2 files changed, 44 insertions(+)
>
> diff --git a/doc/filters.texi b/doc/filters.texi
> index 471ec3f..ade571d 100644
> --- a/doc/filters.texi
> +++ b/doc/filters.texi
> @@ -13196,6 +13196,16 @@ value between 0 and 1 to indicate a new scene; a low
> value reflects a low
> probability for the current frame to introduce a new scene, while a higher
> value means the current frame is more likely to be one (see the example
> below)
>
> +@item concatdec_select
> +The concat demuxer can set the @var{lavf.concat.start_time} and the
> +@var{lavf.concat.duration} packet metadata values which are also present in
> the
> +decoded frames.
> +
> +The @var{concatdec_select} variable is -1 if the frame pts is at least
> +start_time and either the duration metadata is missing or the frame pts is
> less
> +than start_time + duration, 0 otherwise, and NaN if the start_time metadata
> is
> +missing.
Add also a single explanation, like this:
That means that an input frame is selected if its pts is within the
interval set by the concat demuxer.
I wonder if it would make sense to export the input index
(lavf.concat.index), and use it here in place of -1.
> +
> @end table
>
> The default value of the select expression is "1".
> @@ -13270,6 +13280,13 @@ Send even and odd frames to separate outputs, and
> compose them:
> @example
> select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even]
> overlay=y=h
> @end example
> +
> +@item
> +Select useful frames from an ffconcat file which is using inpoints and
> +outpoints but where the source files are not intra frame only.
> +@example
> +ffmpeg -copyts -vsync 0 -segment_time_metadata 1 -i input.ffconcat -vf
> select=concatdec_select -af aselect=concatdec_select output.avi
> +@end example
I guess that the lavf.concat metadata is set so that start_time and
duration corresponds to the inpoint and outpoint interval, right?
> @end itemize
>
> @section selectivecolor
> diff --git a/libavfilter/f_select.c b/libavfilter/f_select.c
> index 2b926e1..14a23d2 100644
> --- a/libavfilter/f_select.c
> +++ b/libavfilter/f_select.c
> @@ -82,6 +82,8 @@ static const char *const var_names[] = {
>
> "scene",
>
> + "concatdec_select", ///< frame usefulness based on pts and frame
> metadata originating from the concat demuxer
probably you can give a more explicative description ("useful" is
pretty generic)
[...]
Looks good otherwise.
--
FFmpeg = Fiendish and Friendly Mortal Portable Erroneous Gospel
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