[flac] decoding with -F

Harry Sack tranzedude at gmail.com
Wed Oct 24 17:35:10 PDT 2007


hi

thx, exactly the explanation i wanted to hear!

i want to try to damage some flac files to hear the effects on the
audio, but does anybody knows if there is a program (like hex editor,
...) that could be used to visually 'search' the  different blocks in
the file, assuming this is even possible.

if it's not, what would be a good way to damage the file in some
places to be able to hear the effect on the audio?

I was also wondering if there is a chance the flac decoder outputs a
wrong sample containing wrong sound rather then outputting a silent
sample or no sample at all. Or is this not possible ?

thx in advance

2007/10/25, Brian Willoughby <brianw at sounds.wa.com>:
> If there are tens of thousands of silent samples, due to errors, then
> you might hear silence.  However, it's more likely to be short enough
> to sound like a glitch.  In fact, fewer erroneous samples will sound
> more like loud distortion than silence, depending upon the difference
> between the missing sample and zero.  This is all assuming individual
> samples.
>
> What's more likely is that a given error will destroy everything from
> the current sample to the end of the block.  That's mostly why the
> documentation mentions silent sections.  If you have a bad FLAC file
> and use -F, you'll probably end up with silent blocks.  The default
> block size for a FLAC file is very similar to the block size of a CD,
> so glitches might sound roughly the same.  One difference is that
> many CD players have digital filters which chirp when there is bad
> data, while a FLAC will not have this same sound effect when errors
> are detected.
>
> Brian W.
>
>
> On Oct 24, 2007, at 07:57, Harry Sack wrote:
> - the decoded sample is error-free and is added to the WAV file
> - the decoded sample has an error but instead this sample is not
> added to the WAV file (so it's just thrown away)
> - the decoded sample has an error but instead a silent sample is
> added to the WAV file (so you can hear in fact silence when there are
> a lot of samples of this kind directly after each other)
>
> is this above correct or are there more situations that can occur in
> the case of corrupted flac files you want to decode using -F?
>
>
>


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