On Mon 3 Sep 4:04 pm Ivo Emanuel Gonçalves wrote: > > can the flac encoder be used to compress non-wave data? > No, it's not possible. That's actually very silly.
Actually, there is no reason it should not run on the data fine, if presented to it appropriately. Input data is a binary stream, and any input will work correctly. With music data, most algorithms rely on the fact that adjacent samples are close to each other in value, so flac works out an equation that fits the data closely, then relies on knowing that the error (the residuals) are small, so it uses a nifty encoding scheme (Golomb-Rice I think) using extra 'padding' bits at the start to efficiently store the small numbers without needing to write the leading zeros as well. This process will work on any data, but for most inputs the output will probably be a bit bigger, as the polynomials will not fit the data well. The compression algorithm you use should really be tailored to the application for which you need it, but any input will work. I checked this on a pdf file: flac --force-raw-format --endian=little --channels=2 --bps=24 --sample-rate=24000 --sign=unsigned Arsene\ Lupin\ contre\ Herlock\ Sholmes.pdf The values you choose for channels etc are purely arbitrary, but will affect the compression (I got a ratio of 1.004, only slightly larger than the input). To decompress: flac -d --force-raw-format --endian=little --sign=unsigned Arsene\ Lupin\ contre\ Herlock\ Sholmes.flac -o test.pdf The output file was perfectly readable, and bit-perfect as expected. Nicholas _______________________________________________ Flac mailing list Flac@xiph.org http://lists.xiph.org/mailman/listinfo/flac