Why checksum uncompressed audio? |
Why checksum uncompressed audio? |
Oct 25 2009, 08:06
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#1
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Group: Members Posts: 231 Joined: 6-April 09 Member No.: 68706 |
FLAC and Wavpack (likely others too) use error detection codes for uncompressed audio data.
Why not for compressed? I could find only 2 differences: -you have to decompress the data to verify correctness, which (sometimes greatly) reduces verification performance -you have more data to be checksumed, which slightly reduces compression / verification performance What am I missing? |
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Oct 25 2009, 09:12
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#2
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Group: Members Posts: 142 Joined: 13-December 04 Member No.: 18660 |
The checksum is meant to proof that the decoded data is the same as the source (e.g. wav file). A checksum of the encoded data will only proof that the file hasn't changed. Off course you could have booth.
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Oct 25 2009, 16:53
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#3
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Group: Members Posts: 231 Joined: 6-April 09 Member No.: 68706 |
The checksum is meant to proof that the decoded data is the same as the source (e.g. wav file). A checksum of the encoded data will only proof that the file hasn't changed. Off course you could have booth. AFAIK (not very far) neither FLAC nor WavPack store checksums of the whole audio, but separate ones for each block. Therefore they aren't useful for comparisons with the source. |
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_mē_ Why checksum uncompressed audio? Oct 25 2009, 08:06
kjoonlee FLAC does store the checksum of the whole audio da... Oct 25 2009, 18:05
Bylie WavPack by default uses blockbased CRC's and, ... Oct 25 2009, 19:18
_mē_ OK, now I get it.
I didn't know that there are... Oct 25 2009, 21:35
odyssey What is your goal? You don't need to decode an... Oct 25 2009, 22:28
_mē_ Silent data corruption.
I verify my music collecti... Oct 26 2009, 14:54
rpp3po Verification time should be disk-bound. I don... Oct 26 2009, 15:15
_mē_ If it was disk bound, FLAC and WavPack would have ... Oct 26 2009, 17:17
rpp3po Just checked an old comparison. Wavpack 4 really o... Oct 26 2009, 17:48![]() ![]() |
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