images.md

Images (GStreamer command-line cheat sheet)

Images can be added to video. In addition, video can be converted into images. This page looks at both types.

Including images in video

Gstreamer can show images on video using the imagefreeze element.

Create a video from an image

export PIC="https://upload.wikimedia.org/wikipedia/en/thumb/8/80/Wikipedia-logo-v2.svg/263px-Wikipedia-logo-v2.svg.png"

gst-launch-1.0 \
    uridecodebin uri=$PIC ! \
    imagefreeze ! \
    autovideosink

Create a video from multiple images

Here's the same image four times, done with the help of compsitor (a mixer):

gst-launch-1.0 \
    compositor name=m sink_1::xpos=263 sink_2::ypos=240 sink_3::xpos=263 sink_3::ypos=240 ! autovideosink \
    uridecodebin uri=$PIC ! videoscale ! video/x-raw, width=263, height=240 ! imagefreeze ! m. \
    uridecodebin uri=$PIC ! videoscale ! video/x-raw, width=263, height=240 ! imagefreeze ! m. \
    uridecodebin uri=$PIC ! videoscale ! video/x-raw, width=263, height=240 ! imagefreeze ! m. \
    uridecodebin uri=$PIC ! videoscale ! video/x-raw, width=263, height=240 ! imagefreeze ! m.

Capturing video output as images

Capture an image as PNG

The pngenc element can create a single PNG:

gst-launch-1.0 videotestsrc ! pngenc ! filesink location=foo.png

Capture an image as JPEG

The jpegenc element can create a single JPEG:

gst-launch-1.0 videotestsrc ! jpegenc ! filesink location=foo.jpg

Capturing images every X seconds

This example captures one frame every 3 seconds, and places it in files with the format img00001.jpg. It also displays the video (as the tee command sends the video to both multifilesink and autovideosink). To change the frequency, change the framerate=1/3. e.g. framerate=2/1 would capture a frame twice a second.

gst-launch-1.0 -v videotestsrc is-live=true ! clockoverlay font-desc=\"Sans, 48\" ! videoconvert ! videorate ! video/x-raw,framerate=1/3 ! jpegenc ! multifilesink location=file-%02d.jpg