We're hiring!
*

GStreamer buffer flow analyzer

Guillaume Desmottes avatar

Guillaume Desmottes
April 25, 2019

Share this post:

GStreamer's logging system is an incredibly powerful ally when debugging but it can sometimes be a bit daunting to dig through the massive amount of generated logs. I often find myself writing small scripts processing gst logs when debugging. Their goal is generally to automatically extract some specific information or metrics from the generated logs. Such scripts are usually quickly written and quickly disposed once I'm done with my debugging but I've been wondering how I could make them easier to write and to re-use.

gst-log-parser is an attempt to solve these two problems by providing a library parsing GStreamer logs and enabling users to easily build such tools. It's written in Rust and is shipped with a few tools that I wrote to track actual bugs in GStreamer elements and applications.

One of those tool is a buffer flow analyzer which can be used to provide various information regarding the buffers exchanged through your pipeline. It relies on logs generated by the upstream stats tracer, so no modification in GStreamer core or in plugins is required.

First step is to generate the logs, this is easily done by defining these env variables: GST_DEBUG="GST_TRACER:7" GST_DEBUG_FILE=gst.log GST_TRACERS=stats

We can then use flow for example to detect decreasing pts or dts:

cargo run --release --bin flow gst.log check-decreasing-pts

Decreasing pts tsdemux0:audio_0_0042 00:00:02.550852023 < 00:00:02.555653845

Or to detect gaps of at least 100ms in the buffers flow:

cargo run --release --bin flow gst.log gap 100

gap from udpsrc0:src : 00:00:00.100142318 since previous buffer (received: 00:00:02.924532910 previous: 00:00:02.824390592)

It can also be used to draw graphs of the pts/dts produced by each src pad over time:

cargo run --release --bin flow gst.log plot-pts
Graph of the pts/dts produced by each src pad over time.


These are just a few examples of the kind of information we can extract from stats logs. I'll likely add more tools in the future and I'm happy to hear suggestions about other features that would make your life easier when debugging GStreamer.


Visit Guillaume's blog.

Comments (0)


Add a Comment






Allowed tags: <b><i><br>Add a new comment:


Search the newsroom

Latest Blog Posts

Asymmetric Multi Processing with Linux & Zephyr on the STM32MP1

03/03/2021

In the embedded world, many modern SoCs such as the ST Microelectronics STM32MP1 now include coprocessor cores which can be used for a wide…

Adding HEVC/H.265 support for NXP's i.MX 8M

17/02/2021

Our recent efforts on the Hantro kernel driver have resulted in the addition of H.264 decoding support and multiple performance improvements.…

Network adaptive streaming with Hwangsaeul

08/02/2021

Hwangsaeul, or H8L, a remote surveillance streaming solution, utilizes the capability of libsrt to collect statistics from open SRT sockets…

Trimming apitrace workload captures for better Mesa testing

01/02/2021

Complex, real-world correctness tests and performance analysis are now possible thanks to gltrim, a new tool recently added to apitrace,…

GStreamer on Windows: adding WebRTC support to a gst-build install

28/01/2021

Earlier this week, WebRTC became an official W3C and IETF standard. GStreamer has a powerful and rapidly maturing WebRTC implementation.…

Implementing a performance boosting algorithm in Coccinelle

21/01/2021

Last year, from June to September, I worked on the kernel development tool Coccinelle under Collabora. I implemented a performance boosting…

Open Since 2005 logo

We use cookies on this website to ensure that you get the best experience. By continuing to use this website you are consenting to the use of these cookies. To find out more please follow this link.

Collabora Ltd © 2005-2021. All rights reserved. Privacy Notice. Sitemap.

Collabora Limited is registered in England and Wales. Company Registration number: 5513718. Registered office: The Platinum Building, St John's Innovation Park, Cambridge, CB4 0DS, United Kingdom. VAT number: 874 1630 19.