New A/V Formats Q&A - Page 2

Eric B · 13th May 2002, 13:43

Is the vorbis 5.1 ready ? And can it be used with a 4.1 system (is the downmix possible in reading ?)

MaTTeR · 13th May 2002, 13:51

@Eric B
Please do some searching and browsing before posting a question of this nature. Vorbis 5.1 has been available for awhile now but full channel coupling isn't implemented yet so expect rather large files. For multi-channel formats your advised to stick with AC3 for now until Vorbis channel coupling matures.

Eric B · 13th May 2002, 14:04

Sorry, but I've searched and not understood.
What does "full channel coupling" mean ? The vorbis 5.1 makes 6 full channel compression ?
I've tried to compress an 382MB AC3 5.1 which make 280MB Vorbis 5.1 whis quality3 an it's very slow. I'would prefer to keep my AC3 file, but I've tried an AC3 in an ogm, and the sound is bad. I've the original SBLive Value. It is a pb with interleave time (I couldn't specify such time as I did in avi with Nandub) or an DirectSound/Wav out pb ?

Neo Neko · 26th January 2003, 21:31

It seems people are asking for it and are having a hard time finding it so I will tack on a link to Nic's wm9enc page here. http://nic.dnsalias.com/WM9Enc.html

hans-jürgen · 13th May 2003, 13:40

Q: Is the new multimedia standard MPEG-4 ready for multichannel MP4 support?
A: Yes, because the MPEG-4 audio part called AAC can contain up to 48 full bandwidth and 15 LFE channels right from the start. This even was one of the main reasons for developing the new format and breaking the backward compatibility with MPEG-1/2 Layer II and III back in the 90's. See http://www.audiocoding.com/wiki/index.php?page=AAC for more infos.

Q: Which real-life MPEG-4 applications have already implemented these features?
A: The open source project FAAC (encoder) including FAAD2 (decoder) is capable of handling at least 7.1 multichannel files, so all freeware applications based on these codecs should be able to support more than two channels: Winamp 2.9x and 3.x, foobar2000, QCD and all other audio players using Winamp plugins.

For video/audio playback there's Mplayer, the MPEG4IP player and Osmo4 which is one of the rare applications that explores the MPEG-4 Systems features at the moment (everything beyond decoding elementary video and audio bitstreams, free authoring tool available). All use or will use FAAD2 for AAC/MP4 playback which will be updated to AAC+ support after the release of Nero Digital. It's unknown at the moment if M4Play from the IBM Toolkit for MPEG-4 can decode more than 2 channels, but nevertheless it's a complete MPEG-4 player based on Java.

Several DirectShow filters for MPEG-4 exist (based on FAAD or other audio decoders) and will be updated to multichannel support soon like 3ivx or do already support it like CoreAAC (audio-only filter). Also free are EnvivioTV and mpegable, though multichannel playback hasn't been confirmed for them yet.

The commercial application Nero Burning ROM is also using FAAD2 for multichannel decoding, so after a bugfix concerning the M/S channel mapping it is able to encode multichannel AAC/MP4 files with its AAC codec (successor of PsyTEL AAC which also suffers from this bug and won't be fixed anymore). The new Nero Digital with a MPEG-4 video codec from Ateme will be the first full-featured MPEG-4 application that uses an AAC+ codec, enabling very low bitrates for the audio part even with 7.1 channels.

Joe_Bloggs · 8th August 2003, 11:27

Hey Christian,
Great work on matroska and all that.

I would like to request that you
touch up your New A/V Formats Q&A post.
It was informative at the time of its
creation but many of its tips etc. are no
longer required.

It is in a prominent position and It could
give the wrong impression to newbies.

I refer to the splitting of ogm files
with nandub. By all means leave it
in as piece of history but perhaps it is
advisable to redirect users to newly created
and better tools that handle ogm and other
container formats. Namely the excellent
VirtualDubMod.

With VirtualDubMod you can edit video and ogm
together as if the sound was PCM ie a .wav file.
Plus it also has matroska support.

13th May 2002, 13:43	#21 \| Link
Eric B Registered User Join Date: May 2002 Location: France/Germany Posts: 119	vorbis5.1 Is the vorbis 5.1 ready ? And can it be used with a 4.1 system (is the downmix possible in reading ?)

13th May 2002, 13:51	#22 \| Link
MaTTeR AC3 5.1 Addict Join Date: Nov 2001 Location: Big Blue Nation_USA Posts: 2,036	@Eric B Please do some searching and browsing before posting a question of this nature. Vorbis 5.1 has been available for awhile now but full channel coupling isn't implemented yet so expect rather large files. For multi-channel formats your advised to stick with AC3 for now until Vorbis channel coupling matures. __________________ Need AC3 & SPDIF setup info?

26th January 2003, 21:31	#24 \| Link
Neo Neko Registered User Join Date: Mar 2002 Location: Kansas City, Missouri Posts: 1,812	It seems people are asking for it and are having a hard time finding it so I will tack on a link to Nic's wm9enc page here. http://nic.dnsalias.com/WM9Enc.html __________________ Opensource will not take over the world. But it will sure improve the lives of most of it! _______________________________________________ Inkscape - Scallable Vector Graphics for everyone. The GIMP - Free raster graphics and photo editing software. Planeshift - Free 3D MMORPG. Cause everyone needs some fun.

13th May 2003, 13:40	#25 \| Link
hans-jürgen Registered User Join Date: May 2003 Location: Hamburg, Germany Posts: 219	MPEG-4 multichannel support Q: Is the new multimedia standard MPEG-4 ready for multichannel MP4 support? A: Yes, because the MPEG-4 audio part called AAC can contain up to 48 full bandwidth and 15 LFE channels right from the start. This even was one of the main reasons for developing the new format and breaking the backward compatibility with MPEG-1/2 Layer II and III back in the 90's. See http://www.audiocoding.com/wiki/index.php?page=AAC for more infos. Q: Which real-life MPEG-4 applications have already implemented these features? A: The open source project FAAC (encoder) including FAAD2 (decoder) is capable of handling at least 7.1 multichannel files, so all freeware applications based on these codecs should be able to support more than two channels: Winamp 2.9x and 3.x, foobar2000, QCD and all other audio players using Winamp plugins. For video/audio playback there's Mplayer, the MPEG4IP player and Osmo4 which is one of the rare applications that explores the MPEG-4 Systems features at the moment (everything beyond decoding elementary video and audio bitstreams, free authoring tool available). All use or will use FAAD2 for AAC/MP4 playback which will be updated to AAC+ support after the release of Nero Digital. It's unknown at the moment if M4Play from the IBM Toolkit for MPEG-4 can decode more than 2 channels, but nevertheless it's a complete MPEG-4 player based on Java. Several DirectShow filters for MPEG-4 exist (based on FAAD or other audio decoders) and will be updated to multichannel support soon like 3ivx or do already support it like CoreAAC (audio-only filter). Also free are EnvivioTV and mpegable, though multichannel playback hasn't been confirmed for them yet. The commercial application Nero Burning ROM is also using FAAD2 for multichannel decoding, so after a bugfix concerning the M/S channel mapping it is able to encode multichannel AAC/MP4 files with its AAC codec (successor of PsyTEL AAC which also suffers from this bug and won't be fixed anymore). The new Nero Digital with a MPEG-4 video codec from Ateme will be the first full-featured MPEG-4 application that uses an AAC+ codec, enabling very low bitrates for the audio part even with 7.1 channels. __________________ ZZee ya, Hans-Jürgen BLUEZZ BASTARDZZ on Myspace, YouTube and Last.fm INDIGO ROCKS on Myspace and Last.fm Last edited by hans-jürgen; 30th June 2003 at 10:18.

13th May 2002, 14:04	#23 \| Link
Eric B Registered User Join Date: May 2002 Location: France/Germany Posts: 119	Sorry, but I've searched and not understood. What does "full channel coupling" mean ? The vorbis 5.1 makes 6 full channel compression ? I've tried to compress an 382MB AC3 5.1 which make 280MB Vorbis 5.1 whis quality3 an it's very slow. I'would prefer to keep my AC3 file, but I've tried an AC3 in an ogm, and the sound is bad. I've the original SBLive Value. It is a pb with interleave time (I couldn't specify such time as I did in avi with Nandub) or an DirectSound/Wav out pb ?

8th August 2003, 11:27	#26 \| Link
Joe_Bloggs Registered User Join Date: Apr 2003 Location: London Posts: 49	Hey Christian, Great work on matroska and all that. I would like to request that you touch up your New A/V Formats Q&A post. It was informative at the time of its creation but many of its tips etc. are no longer required. It is in a prominent position and It could give the wrong impression to newbies. I refer to the splitting of ogm files with nandub. By all means leave it in as piece of history but perhaps it is advisable to redirect users to newly created and better tools that handle ogm and other container formats. Namely the excellent VirtualDubMod. With VirtualDubMod you can edit video and ogm together as if the sound was PCM ie a .wav file. Plus it also has matroska support.