[flac-dev] exhaustive-model-search issue results in multi-gigabyte FLAC file

Leigh Dyer leigh at bandcamp.com
Tue Jul 16 01:51:11 PDT 2013

On 16/07/13 6:31 PM, Martijn van Beurden wrote:
> On 16-07-13 09:07, Leigh Dyer wrote:
>> Hi,
>> On a particular input file, FLAC (testing with current git) greatly
>> inflates its output if I encode at level 7, which enables
>> --exhaustive-model-search. The source is a 24-bit WAV file of about
>> 60MB; flac -6 encodes this to a 43MB FLAC file, but flac -7 produces a
>> 9.1GB (!) file.
> That is a very serious bug, as the encoder should always take verbatim
> frames as its baseline. Can you supply the output of flac's analyse
> function (option -a on the command line) to give us some more
> information on what the resulting file looks like?

Certainly -- I've uploaded the analysis files for both the -6 and -7 
encodes, in case you wanted to compare:


The encode seems to proceed normally until 59% of the way through the 
file, but then it takes a couple of minutes to proceed through to 61% of 
the way through -- it's during this period that the file inflates up to 
9GB in size. The last 39% or so of the encode proceeds normally, too.


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