[Flac-users] flac validation?

Josh Coalson xflac at yahoo.com
Thu Feb 14 11:28:08 PST 2002


--- Martin Blais <blais at iro.umontreal.ca> wrote:
> how much validation has been done on flac? in other words, apart from
> "it 
> works", how can i trust that i'm not going to lose my data?  i have
> seen at 
> least one bug in the bug db where flac seems to produce erroneous
> files.  do 
> you guys have regression tests?  how many, what data?

yeah, this is probably a good question for a FAQ.

first, I should say that I think flac is the only lossless
compressor out there that has a published test suite.  with
the others you rely on the authors testing or the longevity
of the program.  but with flac you can check out the whole
test suite and run it on any version you like, or tweak it
to try your own data.

flac has three sets of tests I run before every release.
all of them are accessible from CVS.  the test suite scripts
are in flac/test/.

first is a set of unit tests which test individual and
internal libFLAC functions.  the source for these tests
is flac/src/test_unit/.

the second is a set where a bunch of audio data in different
formats is run through the encoder and decoder with many
thousands of combinations of options, including all the
-0 .. -8 kind.  the audio tests include waveforms that are
designed to stress different stages of the encoder.  the
source for these tests is in flac/src/test_streams/.

the third is a similar test where relatively large non-audio
files are again run through many thousands of option
combinations.  throwing wild data at the encoder is another
good way to find problems.  the binary data is in a separate
CVS module since it's so large, under test_files/.

I also have an informal set of tests with a collection of
CD rips that I always run.

I don't make a release unless everything passes.  I don't
think there has been a bug that would give you a bad FLAC
file since 1.0.  the one that is logged on sourceforge
looks suspiciously like a hardware problem because it is
highly non-deterministic.  the submitter hasn't got back
with any more info so I will probably close it out since
it's not repeatable.

Josh


__________________________________________________
Do You Yahoo!?
Send FREE Valentine eCards with Yahoo! Greetings!
http://greetings.yahoo.com




More information about the Flac mailing list