flac dev - Jul 2013 - exhaustive-model-search issue results in multi-gigabyte FLAC file

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:

http://wootangent.net/~lsd/blah/6.ana
http://wootangent.net/~lsd/blah/7.ana

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.

Thanks
Leigh

Leigh Dyer wrote:
> Certainly -- I've uploaded the analysis files for both the -6 and -7 
> encodes, in case you wanted to compare:
> 
> http://wootangent.net/~lsd/blah/6.ana
> http://wootangent.net/~lsd/blah/7.ana
> 
> 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.
What happens if you top and tail the file from say 57% to 64% of
the file and try an encode that?

Erik
-- 
----------------------------------------------------------------------
Erik de Castro Lopo
http://www.mega-nerd.com/

On 16/07/13 8:10 PM, Erik de Castro Lopo wrote:
> Leigh Dyer wrote:
>
>> Certainly -- I've uploaded the analysis files for both the -6 and
-7
>> encodes, in case you wanted to compare:
>>
>> http://wootangent.net/~lsd/blah/6.ana
>> http://wootangent.net/~lsd/blah/7.ana
>>
>> 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.
>
> What happens if you top and tail the file from say 57% to 64% of
> the file and try an encode that?
The first time I tried, the resulting file encoded just fine, but after 
trying a few more times, cutting at slightly different points, I was 
able to get a snippet of that section that exhibits the problem. This is 
short enough that I think I can link to it here:

http://wootangent.net/~lsd/blah/snippet6.wav

This results in a 4.1GB file when encoded with -7.

Thanks
Leigh