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doc/filters: clarify metadata and logging for blackdetect

This commit is contained in:
Gyan Doshi 2020-04-13 11:23:24 +05:30
parent 4e0cf81b49
commit 2e2fa2d6e6
2 changed files with 13 additions and 5 deletions
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17
doc/filters.texi
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@ -6532,11 +6532,20 @@ Default is disabled.
Detect video intervals that are (almost) completely black. Can be
useful to detect chapter transitions, commercials, or invalid
recordings. Output lines contains the time for the start, end and
duration of the detected black interval expressed in seconds.
recordings.
In order to display the output lines, you need to set the loglevel at
least to the AV_LOG_INFO value.
The filter outputs its detection analysis to both the log as well as
frame metadata. If a black segment of at least the specified minimum
duration is found, a line with the start and end timestamps as well
as duration is printed to the log with level @code{info}. In addition,
a log line with level @code{debug} is printed per frame showing the
black amount detected for that frame.
The filter also attaches metadata to the first frame of a black
segment with key @code{lavfi.black_start} and to the first frame
after the black segment ends with key @code{lavfi.black_end}. The
value is the frame's timestamp. This metadata is added regardless
of the minimum duration specified.
The filter accepts the following options:

1
libavfilter/vf_blackdetect.c
View File

@ -136,7 +136,6 @@ static int request_frame(AVFilterLink *outlink)
return ret;
}
// TODO: document metadata
static int filter_frame(AVFilterLink *inlink, AVFrame *picref)
{
AVFilterContext *ctx = inlink->dst;