hi flac list, I read on the site about the decoding -F (or --decode-through-errors) feature: ' By default flac stops decoding with an error and removes the partially decoded file if it encounters a bitstream error. With -F, errors are still printed but flac will continue decoding to completion. Note that errors may cause the decoded audio to be missing some samples or have silent sections.' So is it true that when decoding with -F option, there are only 3 possibilities: - 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? thx in advance -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.xiph.org/pipermail/flac/attachments/20071024/b6e0db2b/attachment.htm
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?
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@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? > > >