doc/filters: remove old aformat entry.

[ffmpeg] / doc / indevs.texi

diff --git a/doc/indevs.texi b/doc/indevs.texi
index 782c67fc35a1b189efdb7c6e9d415e9ff8bf3a4e..e699e11f42a181a9d15cd531eb7b7c2a48814fd2 100644 (file)
--- a/doc/indevs.texi
+++ b/doc/indevs.texi
@@ -59,7 +59,7 @@ BSD video input device.
 
 Windows DirectShow input device.
 
-DirectShow support is enabled when FFmpeg is built with mingw-w64.
+DirectShow support is enabled when FFmpeg is built with the mingw-w64 project.
 Currently only audio and video devices are supported.
 
 Multiple devices may be opened as separate inputs, but they may also be
@@ -520,6 +520,13 @@ supported using @command{-list_formats all} for Video4Linux2 devices.
 
 Some usage examples of the video4linux2 devices with ffmpeg and ffplay:
 
+The time base for the timestamps is 1 microsecond. Depending on the kernel
+version and configuration, the timestamps may be derived from the real time
+clock (origin at the Unix Epoch) or the monotonic clock (origin usually at
+boot time, unaffected by NTP or manual changes to the clock). The
+@option{-timestamps abs} or @option{-ts abs} option can be used to force
+conversion into the real time clock.
+
 Note that if FFmpeg is build with v4l-utils support ("--enable-libv4l2"
 option), it will always be used.
 @example