Hi, with the Lame MP3 encoder I reduce the amplitude of the input signal prior to encoding with the --scale option to prevent clipping that can be introduced due to resampling errors. Is Vorbis prone to this sort of clipping? <p>Headless --- >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.
Headless <head-less@dna.ie> wrote:
: Hi,
:
: with the Lame MP3 encoder I reduce the amplitude of the input signal
: prior to encoding with the --scale option to prevent clipping that can
: be introduced due to resampling errors.
:
: Is Vorbis prone to this sort of clipping?
Well, if the record industry would stop trying to put out the loudest CD
ever with each subsequent release...
--
agreenbu @ nyx . net andrew michael greenburg
http://www.nyx.net/~agreenbu/
--- >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 Thursday 03 July 2003 09:17, Headless wrote:> with the Lame MP3 encoder I reduce the amplitude of the input signal > prior to encoding with the --scale option to prevent clipping that can > be introduced due to resampling errors. > > Is Vorbis prone to this sort of clipping?Well, Vorbis doesn't get the output volume level *exactly* the same as the original, 100% of the time... that's just a problem inherent to lossy codecs. As Andrew already mentioned, of course the real problem (IMO) is that studios compress the crap out of everything and then jack it up so the average volume is as high as possible. Which means an error of 1 dB in the encoder could make something clip that didn't before. If you're asking if Vorbis is naturally worse at this than Lame, then the answer is probably not, although lame is a very well-tuned encoder, given the constraint that it's having to use the mp3 format. As far as I can tell, oggenc does not have an option built-in to adjust volume of the input before encoding like lame does. If it's a concern, you can just encode your files normally, and use something like vorbisgain to tag the files so they play back without clipping and at a consistent volume. (Vorbisgain is at http://sjeng.org/vorbisgain.html) Of course, this only works for decoders that are smart enough to read and use vorbisgain tags (which is most of them that handle Ogg Vorbis files anyway, but not all of them); less-sophisticated players will play the file back at full volume. Or, if you prefer actually changing the volume of the data before encoding (rather than merely tagging like vorbisgain does), you'd want something like 'normalize' (http://www1.cs.columbia.edu/~cvaill/normalize/) that you can run on the WAVs before encoding. This has the disadvantage that it makes irrevocable changes to the file, and you can't get back the "original" volume even if you wanted, which bothers some purists. But it has the advantage that the files are played at the same volume everywhere. -- Graham Mitchell - computer science teacher, Leander High School "Man is the best computer we can put aboard a spacecraft... and the only one that can be mass-produced with unskilled labor." -- Wernher von Braun --- >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 Friday 04 July 2003 00:17, Headless wrote:> Hi, > > with the Lame MP3 encoder I reduce the amplitude of the input signal > prior to encoding with the --scale option to prevent clipping that can > be introduced due to resampling errors. > > Is Vorbis prone to this sort of clipping? >It can be, for much the same reasons as mp3. oggenc has a --scale option as well, if you want to use it. Or you could just encode normally, and use the replaygain stuff that others have mentioned. That works well if your player(s) support it. Mike --- >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 03-Jul-2003 Headless wrote:> Hi, > > with the Lame MP3 encoder I reduce the amplitude of the input signal > prior to encoding with the --scale option to prevent clipping that can > be introduced due to resampling errors. > > Is Vorbis prone to this sort of clipping?Yes, it's a lossy codes, so it can slightly change the volumes, just like MP3. AND there is the treble-boost bug which amplifies the signal by a few dB at low (<6) quality rates. <p>Bye. --- >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.