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Gear / Technical Help => Post-Processing, Computer / Streaming / Internet Devices & Related Activity => Topic started by: shackaholic on June 23, 2008, 10:01:41 PM

Title: problem with 24/96 flac file
Post by: shackaholic on June 23, 2008, 10:01:41 PM
I have a recent show as one 24/96 FLAC file. The file is 1.2 GB and was recorded straight to FLAC from his 722.

I basically cannot do anything with this file other than play it.

When decoding it with Trader's Little Helper, I get this error message:

Quote
MMW080619T01.FLAC:  flac fingerprint cannot be checked since it was unset in the streaminfo block.

There were errors.

When I decode with FLAC Front End, I get this error message:

Quote
MMW080619T01.FLAC: WARNING, cannot check MD5 signature since it was unset in the
 STREAMINFO
MMW080619T01.FLAC: done

This is what shntool says about the file:

Quote
C:\Documents and Settings\Mike's\Desktop\mmw2008-06-19.flac24>shntool len *.wav
    length     expanded size   cdr  WAVE problems filename
    74:15.603    2566427540    cxx   --   -----   MMW080619T01.wav
    74:15.603    2566427540 B                     (total for 1 file, 1.0000 over
all compression ratio)

Is there any way I can manipulate this file so that I can open it in Soundforge and start getting it down to 16 bits? Soundforge will not accept the file. I've tried renaming it to .raw extension but I don't understand what setting to check on some of them, such as byte order (little endian vs. big endian) and how many bytes to set the header/trailer.

I've tried using shntool fix on the file but that didn't work either since the file isn't 16/44.

Anyone know what is causing this and better yet how to fix it? Should I just scratch all that and see if the taper still has the recording on his HD on his 722 and just have him re-transfer?


Title: Re: problem with 24/96 flac file
Post by: scb on June 23, 2008, 10:12:00 PM
it's 24/96 and it's 74 minutes?  that's an uncompressed file that's over 2 gigs.  i don't know what you can do to solve it, but I'm guessing that's the issue?
Title: Re: problem with 24/96 flac file
Post by: shackaholic on June 23, 2008, 10:24:08 PM
yeah, it's 74 minutes and was recorded straight to flac in 2496.

uncompressed, it's like 2.5 gigs.

if it were just the fact that it exceeds the 2 gb limit, i could get around that by cutting into two chunks with cd wave and downsampling and then dithering each chunk. then i would think i could join them afterwards, unless if for some reason that's not correct in an audiophile way. i think i even tried this earlier today and it didn't work though. i can't remember if that was the exact way i tried it though since i've attempted so many things on this file.

the error messages about the checksums in the streaminfo are confusing me. i've never seen an error like that.

i
Title: Re: problem with 24/96 flac file
Post by: Chris K on June 23, 2008, 11:23:18 PM
for a workaround, can you play the file on the 722 and send a digi out to an audio card on your cpu and re-record it in wav format?
Title: Re: problem with 24/96 flac file
Post by: Sebastian on June 24, 2008, 03:18:39 PM
It looks like the MD5 checksum of the audio (commonly known as the FLAC fingerprint or FFP) is missing from the file's header. As per the specification of the FLAC format (http://flac.sourceforge.net/format.html#metadata_block_streaminfo), every FLAC file is required to have at least one STREAMINFO metadata block. The STREAMINFO block contains basic information about the file, such as the sample rate and the MD5 checksum.

My guess is that when recording, the 722 leaves 128 bits in the file header blank and writes the MD5 checksum when the whole file is recorded (seems logical because the 722 can't know the checksum until after the recording is complete). I assume there was an error between finishing the recording and updating the file header.

You can try telling the FLAC decoder to just ignore all errors while decoding:
flac -d --decode-through-errors <file>
That way, you will at least be able to decode the FLAC file.