contest rules and OGG format
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- KVRAF
- Topic Starter
- 3057 posts since 9 Apr, 2003
I gather that OGG is a variable-bit-rate format
so I wonder if the technical rules could specify Q5 or lower for OGG, 128 bits or lower for MP3, and either way, time 2:00:00 or less, maybe filesize < 2.2 MB or however it comes out ... something like that?
so I wonder if the technical rules could specify Q5 or lower for OGG, 128 bits or lower for MP3, and either way, time 2:00:00 or less, maybe filesize < 2.2 MB or however it comes out ... something like that?
5 twelve
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- KVRAF
- 12977 posts since 29 Sep, 2003 from Ottawa, Canada
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- KVRAF
- 7672 posts since 9 Nov, 2003 from Netherlands
As far as I know; ogg can be set rate or vbr, just as mp3's so I'd say ogg for the contests should be 128 also
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- KVRAF
- 6496 posts since 26 Nov, 2004 from Frederick, MD
According to www.vorbis.com (their faq page) it sounds like, and I have previously heard that, it is a variable rate compression format only (however, this is based on 2003 information):
Vorbis' audio quality is not best measured in kilobits per second, but on a scale from -1 to 10 called "quality". This change in terminology was brought about by a tuning of the variable-bitrate algorithm that produces better sound quality for a given average bitrate, but which does not adhere as strictly to that average as a target.
This new scale of measurement is not tied to a quantifiable characteristic of the stream, like bitrate, so it's a fairly subjective metric, but provides a more stable basis of comparison to other codecs and is relatively future-proof. As Segher Boessenkool explained, “if you upgrade to a new vorbis encoder, and you keep the same quality setting, you will get smaller files which sound the same. If you keep the same nominal bitrate, you get about the same size files, which sound somewhat better.” The former behavior is the aim of the quality metric, so encoding to a target bitrate is now officially deprecated for all uses except streaming over bandwidth-critical connections.
For now, quality 0 is roughly equivalent to 64kbps average, 5 is roughly 160kbps, and 10 gives about 400kbps. Most people seeking very-near-CD-quality audio encode at a quality of 5 or, for lossless stereo coupling, 6. The default setting is quality 3, which at approximately 110kbps gives a smaller filesize and significantly better fidelity than .mp3 compression at 128kbps.
Vorbis' audio quality is not best measured in kilobits per second, but on a scale from -1 to 10 called "quality". This change in terminology was brought about by a tuning of the variable-bitrate algorithm that produces better sound quality for a given average bitrate, but which does not adhere as strictly to that average as a target.
This new scale of measurement is not tied to a quantifiable characteristic of the stream, like bitrate, so it's a fairly subjective metric, but provides a more stable basis of comparison to other codecs and is relatively future-proof. As Segher Boessenkool explained, “if you upgrade to a new vorbis encoder, and you keep the same quality setting, you will get smaller files which sound the same. If you keep the same nominal bitrate, you get about the same size files, which sound somewhat better.” The former behavior is the aim of the quality metric, so encoding to a target bitrate is now officially deprecated for all uses except streaming over bandwidth-critical connections.
For now, quality 0 is roughly equivalent to 64kbps average, 5 is roughly 160kbps, and 10 gives about 400kbps. Most people seeking very-near-CD-quality audio encode at a quality of 5 or, for lossless stereo coupling, 6. The default setting is quality 3, which at approximately 110kbps gives a smaller filesize and significantly better fidelity than .mp3 compression at 128kbps.
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- The Teach
- 8273 posts since 23 Jul, 2002 from flatness
so ... amend rules to specify .ogg quality level 3 (4 ??? ) acceptable to everyone ???
slainte rob
slainte rob
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- KVRAF
- 12977 posts since 29 Sep, 2003 from Ottawa, Canada
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- KVRAF
- 7672 posts since 9 Nov, 2003 from Netherlands
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- KVRAF
- Topic Starter
- 3057 posts since 9 Apr, 2003
from a table at http://en.wikipedia.org/wiki/Vorbis , it looks like quality level 4 would be about right, with an average bitrate of ~128 kbps
also, an ogg at q4 uses about 900 kb of filesize per minute of audio, less than an MP3 at 128 kbps (which uses about 1000 kb/min)
I learned that you can specify a fixed bitrate for ogg, but that kind of defeats the purpose of using it at all, which is to get better sound for the same filesize (or smaller)
[edit: better make that q4.00, for encoders that can specify fractional quality levels]
also, an ogg at q4 uses about 900 kb of filesize per minute of audio, less than an MP3 at 128 kbps (which uses about 1000 kb/min)
I learned that you can specify a fixed bitrate for ogg, but that kind of defeats the purpose of using it at all, which is to get better sound for the same filesize (or smaller)
[edit: better make that q4.00, for encoders that can specify fractional quality levels]
Last edited by hao nao on Sat Sep 03, 2005 12:36 pm, edited 2 times in total.
5 twelve
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- Banned
- 1842 posts since 4 Aug, 2004 from just right here
What is the advantage of OGG? Is it better quality than wave or is it a smaller file size than wave?
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- KVRAF
- Topic Starter
- 3057 posts since 9 Apr, 2003
both OGG and MP3 are smaller than the source WAV file
assuming compression to about 10% of the WAV's filesize, OGG doesn't seem to flatten the sonic detail as much as MP3
but there might be cases where the MP3 @ 128 comes out sounding better than the OGG @ q4, depending on the source material
assuming compression to about 10% of the WAV's filesize, OGG doesn't seem to flatten the sonic detail as much as MP3
but there might be cases where the MP3 @ 128 comes out sounding better than the OGG @ q4, depending on the source material
5 twelve
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- jaaathmaster
- 2690 posts since 1 Jun, 2001 from Marlow, S. Bucks, UK
Some people seem not to vote for .OGG stuff on the basis that it's not a widely-supported format, for instance, apparently a lot of CD car players apparently play mp3, but few play ogg... Personally I've never had any trouble playing .ogg files (Winamp, VLC and Media Player Classic all do just fine, as does my cheapo DVD player) but it appears some do... Even if .oggs do seem to have more fidelity per kbps than mp3s. It seemed to be causing some controversy in the gossip thread anyway.. Just a consideration..
Funny though, I remember when this new fangled MP3 arrived, it were all Realaudio and .AIFFs afore that lad... Technology's got to move on at some point...
Funny though, I remember when this new fangled MP3 arrived, it were all Realaudio and .AIFFs afore that lad... Technology's got to move on at some point...
Music with dinner is an insult both to the cook and the violinist.
- Beware the Quoth
- 33109 posts since 4 Sep, 2001 from R'lyeh Oceanic Amusement Park and Funfair
Not that many portable players will either...griels wrote:Some people seem not to vote for .OGG stuff on the basis that it's not a widely-supported format, for instance, apparently a lot of CD car players apparently play mp3, but few play ogg...
my other modular synth is a bugbrand
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- The Teach
- 8273 posts since 23 Jul, 2002 from flatness
just to clarify ... im not ditching .mp3 for the contests ... just want to specify a quality rating for .ogg like we specify a bitrate for .mp3 ...
... and not sure how accurate this is but ...
http://wiki.xiph.org/index.php/PortablePlayers
slainte rob
... and not sure how accurate this is but ...
http://wiki.xiph.org/index.php/PortablePlayers
slainte rob
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- KVRian
- 574 posts since 9 Jul, 2002 from Between Autechre and BoC
one more vote for Ogg
Madness wrote:Quit stuffing around posting dumb questions ..... and get on with making music.
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- KVRAF
- 6496 posts since 26 Nov, 2004 from Frederick, MD
pHz, sounds like q4.00 should be the standard for .oggs.
I've never used them but . . . Since .ogg is primarily a variable rate format, and .mp3 is either, have any of you tried comparing file size & quality between .ogg and variable rate .mp3? Depending on the source material variable bit-rate .mp3s are going to be smaller file sizes for the same overall quality. Seems that every time I see a comparison, it's apples to oranges. And why is constant bit-rate .mp3 the standard pretty much everywhere?
I've never used them but . . . Since .ogg is primarily a variable rate format, and .mp3 is either, have any of you tried comparing file size & quality between .ogg and variable rate .mp3? Depending on the source material variable bit-rate .mp3s are going to be smaller file sizes for the same overall quality. Seems that every time I see a comparison, it's apples to oranges. And why is constant bit-rate .mp3 the standard pretty much everywhere?