Image transport very slow when using png compression

Open
#207 0 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

Assessment

Difficulty
5/5
Estimated time
Over a week
Newbie friendliness
25/100
Issue type
Feature
Clarity
Needs clarification
Activity status
Stale
Tech stack
cpp
Domain
robotics

Research direction

Start by reviewing the image_transport publisher behavior described in the issue, including the separate topic requirement for each publisher. Compare the proposed worker-pool approach using cv::imencode with publishing through normal publishers. Done should be a documented or implemented approach that increases PNG frame rate without requiring conflicting topic names.

Written by the indexing model from the issue text.

Description

I'm developing a ROS driver for a camera which is using image transport for publishing the images.

When using png as the format for the compressed stream the frame rate decreases drastically. For jpeg I manage to publish 30 fps while for png I only manage to publish 4 fps when setting the png_level to 1 (which is the minimum). I know this issue is due to the CPU intensive png encoding and is something not directly related to image_transport. However, is there any other approach I could use to increase the frame rate while using png compression?

I thought about using a pool of workers with an image transport publisher each, but it didn't work as each image transport publisher must have a different topic name.

The "best" solution I can think of is to encode the image in multiple workers (using cv::imencode) and later or publish them using normal publishers instead of image transport.

Dominant language
C++
Stars
154
Forks
258
Avg merge
2d 1h
Merged PRs (30d)
3

Getting set up

This project ships no dev container, Dockerfile or contributing guide, so setting up is up to you: start from its README, and see our first-contribution guide for the general steps.

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

More from ros-perception/image_common

All issues in ros-perception/image_common

Similar issues

More C++ issues

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.