.ogg files

[Patrick]

how does one go about converting a file to the .ogg extension, what are the benefits and what extensions can be converted (mp3 for example?)

[Maes]

They are just a compressed audio format, like wma or aac. Thus, any uncompressed or compressed audio format can be compressed to ogg, although if something is already compressed you are more properly referring to "transcoding", e.g. "playing back" the original, turning it into raw uncompressed audio data, and compressing it again in the other format, which is not recommended.

It's preferable to start from the original audio source, without any compression applied to it.

To create .ogg files you need an .ogg vorbis codec.

http://www.vorbis.com/

Licensing and finding binaries is a bit murky, so the fastest way to get a WORKING encoder with an usable interface is to download Audacity or CDex.

[Mindless Rambler]

Ogg Vorbis is higher quality and lower file size than MPEG-1 Audio Layer 3, though it is only higher quality if you convert it from the original audio source like Maes said, otherwise it will be th same as the .mp3 you converted it from, or lower.

[Maes]

Well, that's also quite debatable.

MP3's primary limitation is that it low-pass filters everything at 16 KHz before encoding, while .ogg doesn't try to do that but rather tries to encode everything as faithfully as possible (as do other formats) the result is that for equal bitrates, you can expect .ogg to have greater frequency response than .mp3, but not the same accuracy.

In other words, saying that .ogg will sound as good with the same or even a smaller bitrate compared with mp3 , is a myth, or something that can only be true under restricted circumstances.

(Link coming...)

[Mindless Rambler]

Maes said:

(Link coming...)

You mean this?

http://en.wikipedia.org/wiki/Ogg_Vorbis#Listening_tests

[Patrick]

i guess the real question is if there is any benefit to making an mp3 into an ogg, because i've noticed that ogg files are considerably smaller than mp3 files.

[CODOR]

Maes said:
MP3's primary limitation is that it low-pass filters everything at 16 KHz before encoding, while .ogg doesn't try to do that but rather tries to encode everything as faithfully as possible (as do other formats) the result is that for equal bitrates, you can expect .ogg to have greater frequency response than .mp3, but not the same accuracy.

Not necessarily, Vorbis encoders will apply a lowpass filter if they have to (try encoding something at -q -1 and look at the resulting cutoff around 14kHz). Conversely, encoding MP3s with LAME and the -k option will result in no lowpass filter. Of course, in both cases the encoder is free to throw away any frequencies based upon psychoaccoustics in order to attain the desired bitrate (so yeah, in most cases anything above 16kHz).

In general, listening tests show that Vorbis achieves a high sound quality at a lower bitrate than MP3. Here's some listening tests at Hydrogenaudio that I'll refer to but am too lazy to read right now... :-)

Janitor said:
i guess the real question is if there is any benefit to making an mp3 into an ogg, because i've noticed that ogg files are considerably smaller than mp3 files.

Not really. As Maes points out, encoding one lossy format from another results in data being thrown away twice (it will never sound as good as the previous format, and will almost always sound worse). The only way you'll get the size and quality benefits from Vorbis is if you encode the original lossless files from before they were MP3 encoded.

[Maes]

Mindless Rambler said:

You mean this?

http://en.wikipedia.org/wiki/Ogg_Vorbis#Listening_tests

Nope, I can't find what I was looking for :-( It compared MP3, OGG and WMA, and it showed the results as a series of green, yellow and red bars on a frequency bar.

A green bar extending through some frequencies means "faithful reproduction", yellow meant "preserved frequencies but less accuracy", red meant "absolutely wrong".

MP3 in general was "green" all the way to 16 KHz (with 128k kbps) and had nothing after that, while OGG, with 128 kbps was green up to 14 KHz, and yellow up to 18 KHz or something, while it just got worse with smaller bitrates. So, no real advantage over MP3 there. It just traded some "green" vs a broader "yellow" band.

@Janitor: not turning an MP3 into an OGG (ofc it can be done, but it will be like doing a dub of a dub), but using OGG instead of MP3 in the first place. For now, I can only think of disadvantages in doing so, like incompatibility with 99% of the available portable MP3 players (hell, even the available desktop codecs fail quite often due to format chages), while MP3 is ubiquitous, reliable and stable.

At least it's not an apparently worse format for the same bitrate as MP3, but it's not consistently better for smaller bitrates either, as proponents claim (once they also claimed that 64 kbps WMA = CD quality but that turned out to be complete bullshit).

In any case, if you really need to convert MP3 to OGG, use CDex to convert your MP3 to uncompressed audio first (WAV) and then re-encode the WAVs as OGG. However, be sure to use a higher bitrate than the one the MP3s had: e.g. 160 kbps for former 128kbps MP3s, that's the only way to minimize further artifacts/compression losses. If you have the original CDs or audio files used to make those MP3s, use CDex to rip and encode them directly to OGGs.

[Jodwin]

...also keep in mind that OGG is optimized for variable bitrate, while MP3 is for constant bitrate...

[CODOR]

Maes said:
In any case, if you really need to convert MP3 to OGG, use CDex to convert your MP3 to uncompressed audio first (WAV) and then re-encode the WAVs as OGG.

Or save a step and use foobar2000, which can convert MP3 directly to Vorbis (and a whole pile of other formats)...

[Patrick]

What I'm trying to do is find a more compressed format that i can convert some of the ambient Doom 64 tracks into, simply to keep my wad small, thus making life for mt 56k modem easier when it comes time to upload.

[Maes]

Janitor said:

What I'm trying to do is find a more compressed format that i can convert some of the ambient Doom 64 tracks into, simply to keep my wad small, thus making life for mt 56k modem easier when it comes time to upload.

Sorry, but if you meant "dramatically more compressed" like e.g. twice or thrice as small as good old mp3, for the same quality, you're out of luck.

If keeping the size small is imperative, you'll have to use no more than 64 kbps with ANY format you're using. Some will sound -perhaps much- better than others at that bitrate, especially if you use high quality encoding (e.g. trading a greater encoding time for increased precision with reduced bitrate, I have made some 64 kbps MP3 that sounded quite OK). Even 40 kbps or 32 kbps can sound good for the intended purpose: it's going to be a game soundtrack, muffled behind sound effects. Check out some newgrounds animation: some have excellent sound, and the newgrounds standard is using no more than 40 kbps, yet trading encoding time vs quality can do miracles.

However no currently known compressed music format is going to make a modem's life easier. If what you're trying to compress is just instrumental music, consider using alternatives such a standard MIDI file, or, if available, a tracker module.

[Mindless Rambler]

Maes said:

However no currently known compressed music format is going to make a modem's life easier.

What about FLAC? lol

[Maes]

Mindless Rambler said:

What about FLAC? lol

What about ADPCM compressed WAV ? Or just zipping WAV files? lmao