test_streams.md

Test streams (GStreamer command-line cheat sheet)

Video test streams

Display a test pattern

The videotestsrc element creates test patterns. Display locally like this:

gst-launch-1.0 videotestsrc ! videoconvert ! autovideosink

This should display the test pattern in a window, that looks a bit like this:

There are multiple test patterns available, such as:

Pattern	Example
videotestsrc pattern=snow
videotestsrc pattern=red (and blue, green, white and black)
videotestsrc pattern=pinwheel
videotestsrc pattern=smpte100 (color test bars)
videotestsrc pattern=colors

For the full list of patterns, see https://gstreamer.freedesktop.org/data/doc/gstreamer/head/gst-plugins-base-plugins/html/gst-plugins-base-plugins-videotestsrc.html

Change the shape of a test pattern

To change the width and/or height, pass width and height immediately afterwards, e.g.

gst-launch-1.0 -v videotestsrc pattern=snow ! video/x-raw,width=1280,height=720 ! autovideosink

Audio test streams

Listen to a test audio (beep)

The element audiotestsrc can make a variety of test sounds:

gst-launch-1.0 audiotestsrc ! autoaudiosink

You can change the pitch using the freq property:

# This creates a higher beep:
gst-launch-1.0 audiotestsrc freq=1000 ! autoaudiosink

The mixing page shows how two different frequency audio test streams can be mixed together.

You can change the volume by setting the volume property between 0 and 1. E.g. for a quiet beep:

gst-launch-1.0 audiotestsrc volume=0.1 ! autoaudiosink

White noise

Set wave to white-noise:

gst-launch-1.0 audiotestsrc wave="white-noise" ! autoaudiosink

There are variations (e.g. red noise) - see the docs for a complete list.

Silence

If you need an audio stream with nothing in:

gst-launch-1.0 audiotestsrc wave="silence" ! autoaudiosink

Combining audio and video test streams

Combine both the test pattern and test audio:

gst-launch-1.0 audiotestsrc ! autoaudiosink videotestsrc ! autovideosink