PNG | compress_level of 7-9 are not used because they take too long and do not finish within 1s/image. compress_level=0 is not used because that indicates no compression (raw ARGB format).
| PNG seems to be a lossless encoding, the images seem to be identical pixel by pixel when displayed (i.e. after zooming in extensively on the landing pad). The compression seems to be at around 75-65% of its original size depending on the setting, and the tests were cut down to not include compress_level larger than 6 (as those are generally going to take more than 1 second per image). However, compress_type=2 and compress_type=3 are special in that they take constant time for all compress_level settings (at around 145ms/image). | The entire test takes a very long time run (~45min), and uses approximately 20MB of memory. log_1701815705 | log_1710086119-PI |
AVIF | The quality setting is an integer from 0-100 , but only increments of 10 are tested. Although quality=-1 is a valid setting, it is the same as quality=100 . The chroma setting is for the chroma subsampling during the compressing process. There are 3 settings: quality=100 represents lossless quality, although it is only lossless in the case when chroma=444 .
| There is not a very noticable difference between the different chroma settings. When the quality is from 0 to 20, the picutre quality is bad. When the quality is from 30 to 40, the picture quality is ok. It is noticable but not too bad. When the quality is from 50 to 60, the picture quality is good. There is a difference, but it is small. When the quality is from 70 to 90, the picture quality is great. The difference between the original and the compressed version is almost identical. | The entire test takes a very long time to run (~1h). log_1706392787 | log_1710099000-PI |
HEIF | The quality setting is an integer from 0-100 , but only increments of 10 are tested. Although quality=-1 is a valid setting, it is the same as quality=100 . The chroma setting is for the chroma subsampling during the compressing process. There are 3 settings: quality=100 represents lossless quality, although it is only lossless in the case when chroma=444 .
| | The entire test took a very long time to run (~2h) log_1710115496 | log_1710687824-PI |
JPEG | The quality setting is an integer from 0-100 , but only increments of 10 are tested. The default chroma subsampling for JPEG is 420, it was not varied throughout the test. | | The test didn’t take long to run (~10mins) log_1710721697 | log_1710721997-PI |