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An implicit assumption is that "smaller file size is better" and if this discussion were about audio would probably be mp3 vs ogg vorbis... but flac is the BEST

by mikece 6y ago

An implicit assumption is that "smaller file size is better" and if this discussion were about audio would probably be mp3 vs ogg vorbis... but flac is the BEST to em because I want all of the audio data in the best lossless compression scheme. As a photographer, I would like to have ALL of my image data in a losslessly compressed format as well. What is the FLAC equivalent in the photo/image space?

NikolaNovak 6y ago
TIFF, I believe? https://en.wikipedia.org/wiki/TIFF https://en.wikipedia.org/wiki/TIFF
- sigio 6y ago
  There are lossless versions of PNG, BPF and there is also a lossless JPEG enhancement.
  - mceachen 6y ago
    PNG is always a lossless format. You can only control the level of compression. There are tools that let you re-encode a PNG after applying a lossy filter, but the PNG still encodes it losslessly.
- mceachen 6y ago
  TIFF is just a image container. I'd make sure when you save as TIFF, you specify a bit depth equal to your source image, and a format that isn't lossy (like standard JPEG). If you've got a standard sRGB 8-bit-per-channel image, though, the loss from JPEG at q95 or q100 is negligible, and means your image still enjoys wide app compatibility. If it's something else (like a raw format from a DSLR), the best you can do is retain the original file. Also: don't forget file metadata! I inadvertantly deleted all EXIF headers from a number of my original images many years ago because I used jpegtran (without the -copy option!) to losslessly rotate images. I ended up adding a bunch of heuristics in PhotoStructure to automatically infer missing metadata to repair this mistake.
adrianmonk 6y ago
Some formats that are lossless: PNG, FLIF. Some formats that have a lossless mode: TIFF, WebP, BPG, JPEG XR. FLIF claims to have the best ratios, and they have some benchmark info on their web page (https://flif.info/ https://flif.info/). There are other things to consider like encoding/decoding speed, compatibility, and patents/licensing.
- adrianmonk 6y ago
  [replying to myself since I can't edit now] Oops, I failed to mention JPEG XL! JPEG XL is newer technology, more likely to be supported by browsers, and it pretty much obsoletes FLIF. It's still pretty new but may be the best bet. More info: https://jpeg.org/jpegxl/index.html https://jpeg.org/jpegxl/index.html

by mikece 6y ago

NikolaNovak 6y ago

TIFF, I believe? https://en.wikipedia.org/wiki/TIFF https://en.wikipedia.org/wiki/TIFF

sigio 6y ago
There are lossless versions of PNG, BPF and there is also a lossless JPEG enhancement.
- mceachen 6y ago
  PNG is always a lossless format. You can only control the level of compression. There are tools that let you re-encode a PNG after applying a lossy filter, but the PNG still encodes it losslessly.
mceachen 6y ago
TIFF is just a image container. I'd make sure when you save as TIFF, you specify a bit depth equal to your source image, and a format that isn't lossy (like standard JPEG). If you've got a standard sRGB 8-bit-per-channel image, though, the loss from JPEG at q95 or q100 is negligible, and means your image still enjoys wide app compatibility. If it's something else (like a raw format from a DSLR), the best you can do is retain the original file. Also: don't forget file metadata! I inadvertantly deleted all EXIF headers from a number of my original images many years ago because I used jpegtran (without the -copy option!) to losslessly rotate images. I ended up adding a bunch of heuristics in PhotoStructure to automatically infer missing metadata to repair this mistake.

adrianmonk 6y ago

Some formats that are lossless: PNG, FLIF. Some formats that have a lossless mode: TIFF, WebP, BPG, JPEG XR. FLIF claims to have the best ratios, and they have some benchmark info on their web page (https://flif.info/ https://flif.info/). There are other things to consider like encoding/decoding speed, compatibility, and patents/licensing.

adrianmonk 6y ago
[replying to myself since I can't edit now] Oops, I failed to mention JPEG XL! JPEG XL is newer technology, more likely to be supported by browsers, and it pretty much obsoletes FLIF. It's still pretty new but may be the best bet. More info: https://jpeg.org/jpegxl/index.html https://jpeg.org/jpegxl/index.html