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danielgtaylor / jpeg-archive

Utilities for archiving JPEGs for long term storage.
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Adding PPM export to JPEG-recomrpess #43

Closed maadjordan closed 6 years ago

maadjordan commented 8 years ago

Please allow for export in PPM to allow using the matrix methods on different formats (JP2 or others)..

lfos commented 6 years ago

Not sure. The main purpose of jpeg-recompress is to recompress the input as a JPEG with given quality constraints... We cannot use another output format (especially not a lossless format) for this.

maadjordan commented 6 years ago

The aim is to open the provided methods to other formats. It will be a step in the direction of video support

lfos commented 6 years ago

I still do not understand. The purpose of jpeg-recompress is to find the optimal compression ratio (such that the resulting image is as small as possbile without sacrificing visual quality). How can this possibly work with a lossless image format?

maadjordan commented 6 years ago

Beamr has brought jpeg-mini method from still jpeg image to video. if smallfry can be added to FFmpeg as filter to would help in producing a smaller video files. I've roughly tested jpeg-recompress on video files with mjpeg compression (its frames are jpeg without the huff coef header). I've added example file MJPEG_sample.zip .

lfos commented 6 years ago

Extending to videos makes sense. Extending to a lossless image output format (such as PPM) does not.