From 2e2fa2d6e64e0f87277c507ec9c0fee8eab98533 Mon Sep 17 00:00:00 2001 From: Gyan Doshi Date: Mon, 13 Apr 2020 11:23:24 +0530 Subject: doc/filters: clarify metadata and logging for blackdetect --- doc/filters.texi | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-) (limited to 'doc') diff --git a/doc/filters.texi b/doc/filters.texi index 3931d8d79e..a4f99ef376 100644 --- a/doc/filters.texi +++ b/doc/filters.texi @@ -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. - -In order to display the output lines, you need to set the loglevel at -least to the AV_LOG_INFO value. +recordings. + +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: -- cgit v1.2.3