7MB png resulted in 20MB jpg

[erikng]

I am curious if this is expected. After running a 7MB png (5120x2880 resolution) in guetzli darwin and waiting over 45 minutes for it to process, the file grew by 13MB.

Using a tool like Pixelmator took 5 seconds to convert the same png to a jpg at 84 quality, which resulted in a 4.9MB file.

./guetzli ./in.png ./out.jpg -verbose should result in quality 84, correct?

[guihkx]

Care to share the picture you've used?

[kornelski]

BTW, the quality setting is a made-up arbitrary scale, and it's not comparable between encoders (Guetzli's 84 may look the same as 80 in one encoder, or 95 in another encoder, and it may even vary depending on image content).

[robryk]

@pornel Guetzli's quality was mapped so as to correspond to libjpeg's quality for yuv444 (more precisely, Butteraugli score for quality X is the median Butteraugli score libjpeg generated at quality X on a corpus of images). This doesn't mean that there's an ideal correspondence between the two (libjpeg generates, as expected, a wide range of Butteraugli scores for the same quality on different images), but that comparing them is not completely silly.

@erikng Guetzli's default quality is 95. I'd really appreciate seeing the file you're talking about.

[taestell]

I exported some photos from Aperture as a JPEG at quality "10". Then I exported the same photos as PNGs and used Guetzli to convert them to JPEG (using the default quality setting). In each of my tests the Guetzli-produced JPEG was the larger file. Any advice?

[thehelp1]

The pictures are fine, can you get help to solve the cdi issues. It will make a difference.

…

On Mar 21, 2017 1:02 PM, "Travis Estell" ***@***.***> wrote: I exported some photos from Aperture as a JPEG at quality "10". Then I exported the same photos as PNGs and used Guetzli to convert them to JPEG (using the default quality setting). In each of my tests the Guetzli-produced JPEG was the larger file. Any advice? — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#76 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AZNZWF868JMGB-q3-9eQtbUDEyV5_2z4ks5roB67gaJpZM4Mhfzq> .

[DeeDeeG]

@taestell Not sure if you're being sarcastic, but in case you're being serious: Guetzli exports at quality 95 by default. It also tends to make large-ish outputs for a given quality setting, hopefully looking better to make up for it. Guetzli can only go down to quality 84.

There is no way to output a Guetzli JPG that will be smaller than another typical encoder's quality 10 output.

A quality 10 jpeg is probably unusable 99% of the time. so... I have a feeling you weren't being serious. :|