Harry,
This question belongs on the general [FLAC] list, not the developer
list. The topic would only become a developer issue after it was
determined that a change in the code would be useful and/or possible.
That said, FLAC is already capable of reaching 50% or 40% of the
original. I have seen FLAC reach 30% (ratio = 0.3x) or even less
with my files. It depends upon the content because FLAC keeps all
the content. Other compression formats which are lossy can choose
almost any ratio, because they are throwing away information, and you
can always throw away more. FLAC cannot choose the ratio because it
is keeping all the information, and it must not throw anything away.
The less there is, the lower the ratio.
To put it another way, overly "produced" music will compress less,
while raw recordings of live an natural sounds will compress more.
If you're always seeing 60%, then your CD tracks are probably not
classical or highly-dynamic live jazz music. Death metal white noise
music will probably only compress to about 90% or 80%.
Brian Willoughby
Sound Consulting
P.S. You should carefully study the online FAQ at http://
flac.sourceforge.net/faq.html#general__lowest_bitrate
because it holds the answer to your question. It mentions that
ratios from 100% to 0% are possible, depending upon the track. e.g.
What is the lowest bitrate (or highest compression) achievable with
FLAC?
With FLAC you do not specify a bitrate like with some lossy codecs.
It's more like specifying a quality with Vorbis or MPC, except with
FLAC the quality is always "lossless" and the resulting bitrate is
roughly proportional to the amount of information in the original
signal. You cannot control the bitrate much and the result can be
from around 100% of the input rate (if you are encoding noise), down
to almost 0 (encoding silence).
On Aug 27, 2007, at 04:50, Harry Sack wrote:
hi flac-dev list!
I see, when compressing CD-audio tracks, I can reach up to 60% (ratio
= 0.6x) of the original WAV file after compression. I was wondering
if the FLAC codec could become as good as reaching 50% of the
original WAV file in the future or if we are already at the (almost)
maximum compression possible?
thx
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