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dirkvdb / ffmpegthumbnailer

Lightweight video thumbnailer that can be used by file managers to create thumbnails for video files
GNU General Public License v2.0
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Add PNG compression level command line option #214

Open DarjanKrijan opened 2 years ago

DarjanKrijan commented 2 years ago

Would it be possible to add a PNG compression level option?

I measured the time of PngWriter::writeFrame for a 256x192 image between default compression (6) and 0 compressoin by adding png_set_compression_level(m_PngPtr, 0); there:

default compression: 15.6ms 0 compression: 1.6ms

I have my ~/.cache containing the thumbnails directory symlinked to a volatile ramdisk and rather have the generated thumbnails be generated quicker uncompressed and also loaded quicker by the file manager, saving a good bunch of seconds for larger video directories. For other people an even better compression than the default level 6 might be desired.

I'd do this myself and do a PR but I think someone that worked with this before gets this passed down way quicker.

DarjanKrijan commented 2 years ago

I just noticed gnome based DEs re-read and compress the output of the thumbnailer again before putting them in ~/.cache/thumbnails, adding metadata to the PNG header doing so. In my opinion there's no reason whatsoever to use compression for the actual thumbnailers at all.