Hello. As the subject of my email states, I've noticed that oggenc never encodes the same twice. i.e., encoding the same file twice, using the same settings and same OS, never results in identical files (checked using 'diff'). I know that a randomly generated serial number is put it, but it gets better: a diff (- a -u0) between these two encodings is ~120KiB. Umm... why? Should the diff be around 1KiB, at the most? Also, I've compiled by own libao, libogg, etc. (in Linux 2.4.17) and one of the files I've encoded using these utils has a bitrate 2 bits lower than the same track encoded in Windows 95. Why is this? Is there some way to find out whether my compiler (gcc 2.95.3) is creating degenerate ogg files, reminiscent of the recent RedHat compiler bug posted on vorbis.com? -- Karol Pietrzak PGP KeyID: 3A1446A0 --- >8 ---- List archives: http://www.xiph.org/archives/ Ogg project homepage: http://www.xiph.org/ogg/ To unsubscribe from this list, send a message to 'vorbis-request@xiph.org' containing only the word 'unsubscribe' in the body. No subject is needed. Unsubscribe messages sent to the list will be ignored/filtered.
On Mon, Jan 07, 2002 at 02:57:17PM -0500, Karol Pietrzak wrote:> Hello. > As the subject of my email states, I've noticed that oggenc > never encodes the same twice. i.e., encoding the same file > twice, using the same settings and same OS, never results in > identical files (checked using 'diff'). I know that a randomly > generated serial number is put it, but it gets better: a diff (- > a -u0) between these two encodings is ~120KiB. Umm... why?diff only works properly on ascii text. Use cmp for binary files.> Should the diff be around 1KiB, at the most?No, see above.> Also, I've compiled by own libao, libogg, etc. (in Linux 2.4.17) > and one of the files I've encoded using these utils has a > bitrate 2 bits lower than the same track encoded in Windows 95.MSVC will produce very different floating point optimizations from GCC. The differences are harmless, but enough roudoff behavior will change to slightly alter the exact output. It's harmless. (Note though that there is a win32 bug when using -b in batch mode. This is causing the incorrect bitrate after the first file encoded, and appears right now to be a bug in MSVC) Monty --- >8 ---- List archives: http://www.xiph.org/archives/ Ogg project homepage: http://www.xiph.org/ogg/ To unsubscribe from this list, send a message to 'vorbis-request@xiph.org' containing only the word 'unsubscribe' in the body. No subject is needed. Unsubscribe messages sent to the list will be ignored/filtered.
Karol Pietrzak wrote:> > Hello. > As the subject of my email states, I've noticed that oggenc > never encodes the same twice. i.e., encoding the same file > twice, using the same settings and same OS, never results in > identical files (checked using 'diff'). I know that a randomly > generated serial number is put it, but it gets better: a diff (-The CRC is different as well.> a -u0) between these two encodings is ~120KiB. Umm... why? > Should the diff be around 1KiB, at the most?Try cmp -l | wc -l instead (this gives you the number of different bytes).> > Also, I've compiled by own libao, libogg, etc. (in Linux 2.4.17) > and one of the files I've encoded using these utils has a > bitrate 2 bits lower than the same track encoded in Windows 95. > Why is this? Is there some way to find out whether my compilerDifferent compiler, different rounding errors.> (gcc 2.95.3) is creating degenerate ogg files, reminiscent of > the recent RedHat compiler bug posted on vorbis.com?Use the source, Luke! Or just listen to it... if it sounds right to you, there's no problem (for you, at least). <p>Segher <p>--- >8 ---- List archives: http://www.xiph.org/archives/ Ogg project homepage: http://www.xiph.org/ogg/ To unsubscribe from this list, send a message to 'vorbis-request@xiph.org' containing only the word 'unsubscribe' in the body. No subject is needed. Unsubscribe messages sent to the list will be ignored/filtered.