General questions on mp3 Surround, mp3 SX, and mp3D
Questions related to the Fraunhofer IIS mp3 Surround Evaluation Software V3
Questions related to Fraunhofer IIS mp3 Stereo eXtended (mp3 SX)
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General questions on mp3 Surround, mp3 SX, and mp3D
What is mp3 Surround?
mp3 Surround is a format for storing compressed multi-channel audio material. It allows encoding multi-channel sound data in high quality at bit rates comparable to those currently used to encode stereo material. Most important, the new format is completely backward compatible to existing stereo mp3 software and devices.
What is mp3 Stereo eXtended (mp3 SX)?
mp3 SX is a utility for automatic conversion of two-channel content to mp3 Surround. It guarantees playback with a stable localization of singers and instruments even off the sweet spot. Additionally, it creates an impressive feeling of envelopment using the ambience sounds already present in the stereo source.
What is mp3D?
mp3D improves the quality of audio playback on headphones. Stereo music is enhanced to create a wider sound image and a more pleasant listening experience. Surround sound can be played back with mp3D on any set of stereo headphones, simulating the natural reception of multi-channel sound by the human ear. mp3D calculates the sounds that reach the ears from loudspeakers, reflections and echoes of a listening room. The "out-of-head" localization and the feeling of spatiality achieved that way increases the listening comfort noticeably compared to traditional stereo headphone listening. mp3D can be combined with mp3 Surround and mp3 SX.
Does mp3 Surround support surround configurations other than the 5.1-channel setup?
Yes, although the Fraunhofer IIS mp3 Surround Evaluation Software V3 is limited to a 5.1-channel configuration. Future versions of mp3 Surround encoders and decoders could support other configurations as well (e.g. 7.1 or 10.2). There is no limit for the number of channels that can be supported.
How can I create an mp3 Surround file?
You need the mp3 Surround Encoder available for download in the download section. With this tool mp3 Surround files can be encoded from an uncompressed 6-channel '.wav' file. You can also use the mp3 SX Converter tool available on this website to enhance mp3 stereo to mp3 Surround.
What data rates are supported by mp3 Surround?
mp3 Surround supports data rates from 128 kbit/s or less to 320 kbit/s. To achieve high audio quality, we recommend using data rates not below 160 kbit/s.
How is the sound quality of mp3 Surround compared to other surround formats?
If a high audio data rate is chosen (i.e. 160 kbit/s or more), mp3 Surround provides a multi-channel audio quality that is substantially higher than that of the well-known matrixed multi-channel formats commonly used in today's consumer equipment.
Which operation systems and platforms support mp3 Surround?
mp3 Surround software is available on Windows, Mac OS X, and Linux. Implementations on other platforms, e.g. embedded devices, are possible, if they are multi-channel audio enabled.
How can I play back an mp3 Surround file on PC or Mac?
You can play back mp3 Surround files on any existing mp3 player or device in excellent stereo quality. To enjoy the full surround experience on a PC or Mac, your computer needs an mp3 Surround player application, and a multi-channel sound card connected to a 5.1-channel loudspeaker setup. If you have an mp3D enabled player like the Fraunhofer IIS mp3 Surround Player V3, you can also listen to mp3 Surround sound over common stereo headphones using the mp3D virtual surround processing (press the headphone button).
What software supports multi-channel playback of mp3 Surround files?
The Fraunhofer IIS mp3 Surround Player V3 available from this web site supports multi-channel playback of mp3 Surround files on Windows or Mac. For Windows, there is also a Winamp decoder plug-in available. For Linux based systems, you can obtain a command line mp3 Surround decoder from www.all4mp3.com. mp3 Surround enabled third-party software is available from Magix (www.magix.com), others will follow in the near future.
Can I play regular stereo mp3s with an mp3 Surround Player?
Yes, mp3 Surround players are able to play back regular stereo mp3 files.
Can I play mp3 Surround files with my DVD or mp3 players?
mp3 Surround files play on all conventional mp3 players and devices in excellent stereo quality. The next generation of DVD players may support mp3 Surround, enabling the user to enjoy the full multi-channel experience from mp3 Surround files.
How can I tell whether an mp3 file contains surround data or not?
Currently, there is no separate tool available to detect surround data in mp3 files. mp3 Surround enabled players detect the embedded surround information automagically and play the multi-channel sound.
How do I convert an audio CD to mp3 Surround?
First, encode the audio CD to the mp3 stereo format (e.g. with a third-party application), then use the mp3 SX Converter to create an mp3 Surround version of the files.
How do I convert mp3 files to mp3 Surround?
Use the mp3 SX Converter to create an mp3 Surround version of the files.
Are mp3 Surround files much bigger than regular mp3 files?
No, fortunately not. The algorithm used in mp3 Surround employs psychoacoustics to recreate the surround image out of very compact spatial information. By adding surround information, mp3 file sizes increase by just about 10 percent.
What processing power is required for playing mp3 Surround?
The Fraunhofer IIS mp3 Surround Player V3 runs smoothly on CPUs of 600 MHz or more. Decoding the six channels needs around three times the processing power of decoding stereo mp3.
Can mp3 Surround streams be output through an S/PDIF connection?
Yes, in the same way as mp3 streams.
Which products do already support mp3 Surround?
mp3 Surround enabled products are already available from Magix (www.magix.com). There have been further product announcements by several companies including DivX and Medion. See the press section for details and news.
Questions related to the mp3 Surround Evaluation Software V3
Do I need 5.1-channel content to create an mp3 Surround file?
Using the Fraunhofer IIS mp3 Surround Encoder, mp3 Surround files can only be created from uncompressed 5.1-channel '.wav' files. With the mp3 SX Converter, mp3 Stereo files can be enhanced to mp3 Surround and played back in multi-channel. mp3 Surround files created that way contain a flag signalling that they have been created from 2-channel content. mp3 Surround Encoder, mp3 SX Converter, and mp3 Surround Player are available for download from this website.
How can I make sure that my '.wav' file contains 6 channels?
On a Windows PC you can view the file properties of the '.wav' file via the context menu (right mouse button, Properties, File info). Files that can be used with the Fraunhofer IIS mp3 Surround Encoder show:
- Bit rate 4608 or 4233 kbit/s
- Resolution 16 or 24 bit
- Channels 6
- Sampling rate 44 or 48 kHz
- Audio format PCM
Other source file formats are not yet supported. If in doubt, compare the properties of your '.wav' file with the '6_Channel_ID.wav' file that is available for download.
What data rates are supported by the mp3 Surround Player V3?
The mp3 Surround Player of the Evaluation Software V3 supports all common bit rates.
Certain mp3 files don't play on the mp3 Surround Player 3.0. Why that?
There are two possible reasons: Either the files do not contain valid mp3 data, or there are certain special characters in the file name or file path, like apostrophes.
What data rates are supported by the mp3 Surround Encoder available on this website?
The mp3 Surround Encoder with user interface available on this website supports 192 kBit/s at a sampling rate of 44.1 and 48 kHz for 5.1-channel surround material.
What data rates are supported by the command line mp3 Surround codec available at www.all4mp3.com?
The mp3 Surround command line encoder can handle data rates between 128 and 320 kbit/s at sampling rates of 44.1 or 48 kHz for 5.1-channel surround material. For stereo and mono material, the encoder also supports further data rates and sampling rates. Encoder and decoder do not have any run-time limitations.
Which operation systems and platforms are supported by mp3 Surround Evaluation Software V3?
The Fraunhofer IIS mp3 Surround Player V3 and the mp3 Surround Encoder run on Microsoft Windows 2000/XP with Direct X 9.0 installed, and on Mac OS X. Support for Linux is available through the mp3 Surround command line tools available at www.all4mp3.com.
What are the hardware requirements for playback of mp3 Surround files?
You can play back mp3 Surround files on any existing mp3 player or device in excellent stereo quality. To enjoy the full surround experience on a PC or Mac, your computer needs an mp3 Surround player application, and a multi-channel sound card connected to a 5.1-channel loudspeaker setup. If you have an mp3D enabled player like the Fraunhofer IIS mp3 Surround Player V3, you can also listen to mp3 Surround sound over common stereo headphones using the mp3D virtual surround processing (press the headphone button). The player needs about 600 MHz CPU power to run smoothly.
What do the different mp3D modes in the mp3 Surround Player mean?
For mp3 Surround content the mp3D algorithm models the surround sound reception by the human ear. Ears (and heads) have different shapes, so the sound received by the hearing varies from one person to the other. To account for that, the mp3D module in the mp3 Surround Player 3.0 offers four different modes users can select to find the mode that fits best to their ears.
How can I purchase an unlimited version of the mp3 Surround software?
The software is unlimited for personal and non-commercial use. For commercial licensing, please contact our official licensing partner THOMSON on www.mp3licensing.com.
Does the mp3 Surround Evaluation Software V3 have any limitations?
The use of the software is allowed for personal and non-commercial purposes only. For business matters, please contact our official licensing partner THOMSON on www.mp3licensing.com. The mp3 Surround player is not limited in time. However, the mp3 Surround Encoder with user interface is limited in time till 31st December 2013.
Questions related to the Fraunhofer IIS mp3 Stereo eXtended (mp3 SX)
What is mp3 SX?
mp3 SX is a utility for automatic conversion of two-channel content to mp3 Surround. It guarantees playback with a stable localization of singers and solo instruments even off the sweet spot. Additionally, it creates an impressive feeling of envelopment using the ambience sounds already present in the stereo source. The mp3 SX demo software converts stereo mp3 files into mp3 Surround files. Other source formats like '.wav' files are not supported in the current version of the software.
How can I listen to mp3 SX?
To play back mp3 Surround files created with mp3 SX, an mp3 Surround Player or Decoder of Version 2.0 or newer is required. With the mp3 Surround Player 3.0 available in the download area, surround content can be played back either on a 5.1-channel loudspeaker setup or on stereo headphones using the mp3D virtual surround technology. As mp3 Surround files (and therefore also mp3 SX-created files) are backward compatible to mp3 Stereo, the files can also be played back with any conventional mp3 player, but in this case without the benefits of the multi-channel reproduction.
Why do I receive error messages from the mp3 SX Converter with certain input files?
Probably, the files do not meet the current specification for input files. mp3 SX currently only supports input files with the following properties:
- A valid stereo mp3 bitstream
- 44100 Hz sampling rate
- 128 kbps to 192 kbps CBR, or medium to high quality VBR
Some mp3 stereo input files are rejected with "Error in mp3 input", even though they seem to meet the above specification. Why that?
These mp3 files may have synchronisation errors in the mp3 bitstream which are compensated through resynchronisation by some mp3 players. This sometimes leads to a "clicking" noise in the audio output. Unfortunately these (partially broken) files are not suitable for the conversion process to mp3 SX. Future versions of the mp3 SX conversion software may be able to fix partially broken mp3 input bitstreams.
mp3 SX successfully created an mp3 Surround file, but during playback most of the sound seems to come only from the center channel. What's wrong?
The resulting audio redistribution of the conversion process depends on the stereophonic quality of the input mp3 file. If you use a dual-mono-like mp3 input file the resulting output of the mp3 SX conversion will have a dominant center channel.
mp3 SX successfully created an mp3 Surround file, but during playback there`s not much ambience sound coming from the rear channels. What's wrong?
One design goal of mp3 SX was not to introduce artificial reverberation (or similar processing) into the output file. If there is only few ambience sound in the mp3 Stereo input file, the resulting output of the mp3 SX conversion will have only little ambience sound in the rear channels as well.
What happens to my Tags (e.g. ID3) of the original mp3 Stereo input file during the conversion process?
ID3 V3 tags in mp3 Stereo input files are supported and should be available in the mp3 SX output as well. ID3 V1 tags are currently not supported and will be lost in the mp3 SX output file as well as all other forms of additional binary data (e.g. other forms of tags) at the beginning or at the end of the mp3 Stereo input bitstream.
