Mpeg Multichannel Audio

Multichannel Audio

Since release 0.5.3 encode2mpeg supports Mpeg Multichannel Audio format. This means that you can have a standard SVCD with more than 2 audio channels per audio stream. You can therefore convert a DVD with AC3 5.1 audio to SVCD and keep all the 5.1 audio channels. If your audio equipment is not MPEG Multichannel compliant, you will hear a normal stereo sound.
In order to select MPEG Multichannel audio add the options: -mp2 musicin -mpegchannels 6 to your encode2mpeg command line. In Mpeg Mode you need also to add -replex and use -encode 0:m:i. Remember, it makes sense to use these options only if your source video has more than 2 audio channels in the audio stream. In order to mantain a reasonable audio quality you should keep the abr to 384 (it is the default for multichannel audio). You may also need to reduce the vbr to a lower value (2355) in order to keep the total bitrate within the SVCD specifications.

Example Direct Mode:

encode2mpeg -o SVCD5.1 dvd://1 -svcd -n p -aid 128 -mp2 musicin -mpegchannels 6

Example Mpeg Mode:

encode2mpeg -o SVCD5.1 dvd://1 -svcd -n p -aid 128 -mp2 musicin -mpegchannels 6 -mpeg -encode 0:3:2 -replex

If you use Mpeg Multichannel Audio encoding on regular basis, please contact me. There may be still some adjustement that can be done.

How to test your audio equipment

You can easily test if your audio equipment is MPEG Multichannel compliant:

Make a Multichannel Audio SVCD
Download this MPEG Multichannel audio track called SVCDTest.mp2 and make a SVCD with encode2mpeg:
```
encode2mpeg -o TEST -testmca SVCDTest.mp2 -svcd -n <NORM>
```

Put the SVCD in your hardware player.
- If your equipment is MPEG Multichannel compliant, the voice annoucement and the accompanying noise test tone for each channel should come out of the corresponding speaker. Depending on your setup, the deep-bass LFE test tone may emerge from your subwoofer (if any) and/or from one or more of the front speakers. The voice annoucement for the LFE channel will come out of the left speaker only. If you hear no deep-bass test tone at all when your hear “LFE” annoucement, the bass-management controls may need adjustment or your speakers are not capable of producing sounds below 70Hz. Do not forget to disable your dolby surround decoder (and any DSP effects) if you want a real MPEG multichannel compliance test.
- If your equipment is not MPEG Multichannel compliant, you will hear the audio only from the left and right speakers.
- If your equipment is not MPEG Multichannel compliant, but it supports Dolby Surround Prologic, then, after enabling the dolby surround decoder, you should be able to listen the sound from the left, center and right speakers. The surround speakers may also work acting as if they were a single speaker (the same sound will came from the left and right surround speakers). The LFE speaker should not work.

Software requirements

In order to make MPEG Multichannel Audio you need to install the MPEG-2 Audio Simulation Software Distribution 10. The README contains step by step instructions about its installation.

Reference

How to make 5.1 SVCD. Good general explanation of MPEG Multichannel Audio, windows oriented.
How to make a multichannel MPEG-2 Audiostream. Linux oriented.
Creating a Multichannel Audio SVCD. Same information as the previous web site, but windows oriented.
HOWTO Create a SVCD with MPEG Multichannel Sound. Focused on conversion from DVB recordings, linux oriented.

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