How to generate a GStreamer pipeline diagram

Introduction

This page will allow you to create a useful diagram of your pipeline, as described in GStreamer's Basic Tutorial.

Steps

1. Install dot:

sudo apt-get install graphviz

The dot command is available in the graphviz package.

2. In the target, run:

export GST_DEBUG_DUMP_DOT_DIR=/tmp/

This will place the .dot generated files in your /tmp/ directory, you can change that directory if you need to.

3. Run your pipeline, for example:

gst-launch-1.0 audiotestsrc num-buffers=1000 ! fakesink sync=false

After the pipeline is over, you can see the .dot generated files with:

ls /tmp

The "PLAYING_PAUSED" one is typically used to generate the diagram.

 0.00.00.972540004-gst-launch.NULL_READY.dot
 0.00.01.051387461-gst-launch.READY_PAUSED.dot
 0.00.01.074729712-gst-launch.PAUSED_PLAYING.dot
 0.00.12.187852589-gst-launch.PLAYING_PAUSED.dot
 0.00.12.201485839-gst-launch.PAUSED_READY.dot
 psplash_fifo

4. In your host machine, generate the diagram from the dot file

This step implies that you know how to transfer the .dot file from your target to your host machine. Once you've done that, you can generate the .png image using the dot command in your host:

dot -Tpng 0.00.12.187852589-gst-launch.PLAYING_PAUSED.dot > pipeline.png

5. Open up your image

Once the image has been created, you can open it using the default image viewer with the command below or with your favorite image viewer.

xdg-open pipeline.png

You will see a graph like the one in Figure 1.

Figure 1: Pipeline's graph

Helper Script

Sometimes you can get a lot of different DOT files generated. If you want to convert each one of them to PNG pictures, you can use this script. Specify the folder where your DOT files are (DOT_FILES_DIR), and the folder where you want to place the generated PNG files (PNG_FILES_DIR).

DOT_FILES_DIR="fs/fs/graphs"
PNG_FILES_DIR="fs/fs/graphs"

DOT_FILES=`ls $DOT_FILES_DIR | grep dot`

for dot_file in $DOT_FILES
do
  png_file=`echo $dot_file | sed s/.dot/.png/`
  dot -Tpng $DOT_FILES_DIR/$dot_file > $PNG_FILES_DIR/$png_file
done

Generate from a GStreamer application

We will see how to create the do file from a C and Python application.

C

Add this to your app after all the elements are created and linked and before you set your pipeline to NULL:

GST_DEBUG_BIN_TO_DOT_FILE(pipeline, GST_DEBUG_GRAPH_SHOW_ALL, "pipeline")

And run the app like:

GST_DEBUG_DUMP_DOT_DIR=. ./application

Python

For Python, use the following:

Gst.debug_bin_to_dot_file(pipeline, GST_DEBUG_GRAPH_SHOW_ALL, "pipeline")

And run the app like:

GST_DEBUG_DUMP_DOT_DIR=. python3 ~/application.py

Convert to PNG

Where you ran the application, you can find a file named pipeline.dot, move it to your computer and convert it to PNG format:

dot -Tpng pipeline.dot > pipeline.png

Open the pipeline.png

xdg-open pipeline.png

You should see a graph like the one shown in Figure 1.

See Also

• GStreamer Debugging

GStreamer Pipeline Diagram Links

• GStreamer Debugging Tools Tutorial.

• DOT Language

• Graph Visualization Software

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