Guetzli simple to use

guetzli github Warehouse

guetzli github

Introduce

Guetzli It's a kind of JPEG Encoder , Designed to achieve excellent compression density with high visual quality .Guetzli The resulting image is usually better than libjpeg The resulting image of the same quality is small 20-30%.Guetzli Generate order only （ Non progressive ）JPEG, Because they provide faster decompression speed .

Installation and use

It's easy to install according to the documentation , It's just more . My side is based on docker To achieve the , The generated image file has been pushed to the remote , You can use docker pull keyson/guetzli:latest Get mirror .

Container generation ：

docker run -itd --name guetzli-test -v D:\docker_com\guetzli-docker\sync\images:/data/sync --privileged=true keyson/guetzli

Into the container ：
docker exec -it -u root guetzli-test /bin/bash

Run the command guetzli, You can see the following instructions ：

[email protected]:/data/sync# guetzli #  Due to the soft chain in the image , Call anywhere guetzli All right 
Guetzli JPEG compressor. Usage:
guetzli [flags] input_filename output_filename

Flags:
  --verbose    - Print a verbose trace of all attempts to standard output.
  --quality Q  - Visual quality to aim for, expressed as a JPEG quality value.
                 Default value is 95.
  --memlimit M - Memory limit in MB. Guetzli will fail if unable to stay under
                 the limit. Default limit is 6000 MB.
  --nomemlimit - Do not limit memory usage.

There are few parameters , And it's easy to understand . Parameter description ：

• –verbose： Print a detailed trace of all attempts at standard output .
• –quality Q ： Target visual quality , With JPEG Mass value representation . The default value is 95.
• –memlimit M： With MB Memory limit in units . If you can't keep below the limit ,Guetzli Will fail . The default limit is 6000 MB.
• –nomemlimit： Unlimited memory usage .

A simple example

I use an original image with the size of 1592KB Pictures of the . Use Guetzli On the 4 Compress again to see the result .
for the first time
guetzli th15.jpg output.jpg

The second time
guetzli output.jpg output2.jpg

third time
guetzli output2.jpg output3.jpg

The fourth time
guetzli output3.jpg output4.jpg

You can see the state of the runtime container , It really eats memory ：

You can see the result ：

The original size of the picture is 1592KB Of （ On my computer ） After four times of compression , Turned into 653 KB, The important thing is that it is difficult to see whether the image quality is reduced . This is really awesome .

Conclusion ： have access to guetzli Compress the picture many times . Of course, if you want to finish it at one time , Parameters can be changed to reduce quality .

matters needing attention

• Guetzli Use a lot of memory . According to official documents , Should be 1Mpix Provide 300MB Of memory .
• Guetzli Used a lot of CPU Time . Every time 1MPix The input image uses approximately 1 Minutes of CPU.