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Old 7th January 2004, 22:48   #5  |  Link
KpeX
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Vorbis & OGG FAQ [Replaced by Opus]

1. What is OGG? What about Vorbis? What's the difference?

[Like we can see in wikipedia Opus replace Vorbis (and Speex) and can use OGG container or also MKV, WEBM, MPEG-TS and MP4.
It have better performance and compatibility than Vorbis. See also both encoders in hydrogenaudio wiki: Opus and Oggenc]

Vorbis is an open-source general purpose lossy encoded audio compression format developed to be free and completely unpatented.

OGG is the native container for Vorbis, it can also contain other audio formats such as FLAC and Speex. Referring to OGG audio is technically incorrect just as referring to AVI audio or MP4 audio is incorrect, all of these refer to containers. You may have also heard of OGM, which is a modification of OGG to support video, other types of audio, chapters, subtitles, and more. For more information see the OGM FAQ.


2. How can I encode to Vorbis?

[Only the Rarewares links work and have the last recommended Vorbis encoders. Also the Opus tools, and here Opus 1.3.
And ffmpeg support also Vorbis and Opus codecs. The rest of links are oldies.]

You can download OagMachine, BeSweet or HeadAC3he to transcode your AC3 into an Ogg Vorbis file. As usual Doom9 has ()an excellent guide to get you started. A good start point for quality(q) settings is around q2 and this will provide you with a file that averages 96kbps. Unlike MP3, when discussing Vorbis, we dont mention bitrates but discuss in terms of -q modes(quality).

As vorbis is an open-source audio compression format, there are many encoders available, and although they are often referred to as 'forks', they are fully compliant Vorbis encoders. A list of the most common encoders follows:

1) Xiph 1.1.1: The 'official' Ogg Vorbis encoder. (Download link).
2) aoTuV: vorbis tuning by Aoyumi, found to have excellent performance in listening tests. Aoyumi's earlier tunings are now incorporated into the official libvorbis 1.1, but further betas are available from Aoyumi's site.(Homepage), libvorbis dlls.
3) QKTune: A vorbis tuning by QuantumKnot. (Download).
4) GT3b2: A vorbis tuning by Garf. (Download).

There are many more tunings available, the best source for your Vorbis software needs is usually to check out the Vorbis page at Rarewares.


3. How can I upgrade BeSweet or HeadAC3he to a different version of Vorbis?

For BeSweet: If BeSweet finds libvorbis.dll in the besweet directory, it will use that instead of the OGG Vorbis DirectShow filters. Note that for some compiles you'll also need libmmd.dll in the same directory. Get them both from RareWares.

For HeadAC3he: HeadAC3he uses a special vorbis.dll for encoding, get it once again from RareWares.

[We don't need now BeSweet or HeadAC3he]

4. GT3b1? 1.0.1? Which encoder version should I use? What are the best settings?

[Hydrogenaudio wiki for Vorbis and Opus]

Different encoder versions have different bitrate tunings. Vorbis 1.x is well tuned for low bitrates, GT3b1 has some high-bitrate enhancements, and development continues of course. AoTuV versions perform consistently superior in vorbis listening tests. Combined versions are available as well. In general, the -q settings are excellent VBR presets and usually don't need additional parameters. For more information see (Hydrogenaudio's recommended Vorbis encoders and settings).

5. Is it possible to transcode to 5.1 channel vorbis?

Yes, Vorbis supports multichannel audio. Correct channel coupling has yet to be implemented as of Vorbis 1.1.1 so in general it is not recommended when transcoding from AC3; the bitrate required to get a good quality 5.1 Vorbis stream will likely be close to as high as the original AC3 stream.

[Of course Opus also support multichannel]

6. What containers will allow me to use Vorbis + Video? Will Vorbis in AVI ever work?

Currently, Matroska and (OGM) support Vorbis with video quite well. Vorbis in AVI will probably never work due to the complexity of Vorbis streams and the difficulty of correctly synching such a stream in AVI. However, AVI works with many other things that it's not supposed to so who knows.

[Opus is supported in MKV, WEBM, MPEG-TS and MP4]

7. Is it possible to pass 5.1 vorbis over S/PDIF?

There are not any known receivers or amps that support Vorbis decoding, so raw Vorbis cannot be passed over S/PDIF. However there are several filters that support reencoding six channel audio to AC3 on the fly: (Dolby Out DS) filter by Haaan , and AC3Filter can be used to encode AC3 over S/PDIF on the fly. Although this reencoding process will theoretically result in a quality loss, using the full 640 kb/s bitrate allowed will result in an excellent listening experience.

[The same for Opus, but now with HDMI (instead SPDIF) conexion the players can send PCM multichannel decoded from Vorbis or Opus]

8. How can I encode to OGG vorbis under linux / *nix?

The vorbis tools ( for encoding and decoding ogg ) are part of most modern linux distributions, check your distributions' repositories for binary packages. As always debian users can get plenty of vorbis apps from (www.rarewares.org/debian.html.) You can also grab and build the source from vorbis.com. For basic encoding/decoding needs, you'll want to install libogg, libvorbis, and vorbis-tools (in that order).

Vorbis encoding is also supported in (VLC) and several other encoding tools.

[And also with ffmpeg for linux]

Last edited by tebasuna51; 29th September 2021 at 10:11.
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