Yes, WavPack is second in my list. FLAC doesn't preserve every chunk? I thought it did. I only gave a quick try but it seemed to have preserved even the most obscure chunks. Let me check: it even seems to preserve "MIDI note associated to marker", which is a very unknown metadata used by SoundForge (& even defined in a buggy way), so I assumed it was saving them transparently.
Btw, what do you think of this? http://www.hydrogenaudio.org/forums/index.php?s=95a0210a0ba3304eca44ac3bd57990cb&showtopic=73895 (didn't know where to post this, that forum seemed related) Brian wrote in a previous answer: "Another consideration is that flac compresses quiet audio files more than loud audio files." So I thought: imagine a pre-processing coupled with FLAC. It would take frames out of the whole song, and try to cross-correlate them with the song itself. When it finds strong matches (under a certain threshold, and starting with a couple of matches), the frame is saved to a pool, and it's subtracted from the song. Then you FLAC the (small) pool, and the song, full of near-silent spots (& silence where pure repetitions occured). At decode time, you unFLAC the pool and the song, and you add back the frames from the pool to the song. I haven't experimented yet, but let's say I try to correlate frames with the song, and I get something like 20 near-repeats, I may end up with a very silent "song leftover", still as long as the song, but maybe in 4bits worth or something? But it would also have bumps of original audio (that didn't find any matching frame). The thing is, I don't really know how FLAC compresses so I don't know if it would compress the "leftover" so much better. And I don't really know how much matching frames you'd find out in music out there, it would be very genre-dependent. But I'm surprised that no one really investigated this (there were old discussions in that forum). Sure, streaming is important, but it's common to fully download a song. As I wrote, I tried various compressors on a drumloop repeated 4 times, and none could benefit from this. It's only a matter of statistics to know how much often repetitions happens in music out there, but it could work more intelligently, like by normalizing matching frames maybe, to even detect repetitions at different levels. Or work in the freq domain. Afterall, music is based on repetition. And repetition is compression's best friend. At the same time this wouldn't be very interesting for my need, which is to compress short samples. Now here too there could be a similar algo, if it's tonal, cross-correlation would detect matching frames, only at a smaller level. Imagine if you convert a violin sound into a pitch period somewhere in its middle, and the residual from that the subtraction of that pitch period in repeated frames. I think the residual would be rather quiet. > "Didier Dambrin" <[email protected]> wrote: > ... >> I like FLAC on the paper because of its metadata preservation, in that >> riff >> tag, which is critical for my needs. > > Try using WavPack, http://www.wavpack.com/ > > This can losslessly compress 32-bit floating > point WAVE-EX files, and faithfully preserves > every chunk (which FLAC does not do). It is > also free. > > Regards, > Martin > -- > Martin J Leese > E-mail: martin.leese stanfordalumni.org > Web: http://members.tripod.com/martin_leese/ > _______________________________________________ > Flac-dev mailing list > [email protected] > http://lists.xiph.org/mailman/listinfo/flac-dev -------------------------------------------------------------------------------- _______________________________________________ Flac-dev mailing list [email protected] http://lists.xiph.org/mailman/listinfo/flac-dev
