Step 5: MeGUI: Audio Encoding Options
Now it's time to set up the audio encoding options. If you've followed this guide for DVD conversion, then the demuxed audio track we selected in the D2V Creator should already be loaded in (if not, load in the .ac3 file that was created). If you are not converting from a DVD source, then you can either load in a separate audio file or if you edited the AviSynth script (set "audio=true"), then load in the AVS file into the "Audio Input" section (meaning both video and audio inputs are the same AVS file). If you want more than one audio track, right click on this audio aread and select "New Track". If you changed your mind about including an audio track, click on the "X" button to remove the audio from being included.
Now we select an audio codec to use. The PS3 supports AAC LC (low complexity), up to 5.1 channels. To be able to enjoy 5.1 channel audio, you will need need a sound system that is able to either decode AAC through optical or HDMI input, or if you don't have a decoder for AAC, one that accepts PCM 5.1 through HDMI. If you do not meet these requirements, the audio output will only be stereo. Further instructions will be provided later on in regards to setting up the PS3 to output 5.1 AAC if you do indeed have the equipment to be able to decode AAC or play PCM 5.1. As mentioned previously, there are two alternate methods for making a H.264/AC3 file and if you are following this alternative method, skip to the "Alternative AC3 Method" section below.
Another requirement for 5.1 audio is pretty obvious - your input must be 5.1, otherwise, there's no point in having a 5.1 track. Through AviSynth, MeGUI will be able to detect your audio to be 5.1, but only if your DirecShow based decoders can detect the 5.1 audio. For example, with QuickTime HD inputs I found that I needed to install the QuickTime Alternative software before 5.1 audio gets recognised within MeGUI. With DVD/AC3 inputs, 5.1 tracks will automatically be detected without having to install any other piece of software.
So should you choose to include a 5.1 channel AAC soundtrack even if you do not have the equipment to decode it? Well, I think it's probably worth the trouble since it beats having to re-encode all your video files when you get the equipment to do so in the future. The downside is that the file size will be a bit bigger, but it won't be by much.
Select one of the "Nero AAC" profiles, such as "NDAAC-LC-MultiChannel-192Kbps" as the "Audio profile". Just like the video profiles, you can click on "Config" to edit the profile or create your own - as long as you ensure the "AAC-Profile" is set to "AAC-LC", and "Output Channels" is set to "Keep Original Channels", it should all work with the PS3 and ensure 5.1 output. The only setting you might want to change is the bitrate (192 Kbps should be enough for most encodings, you might want to increase it to 256 to give it an extra high quality).
For more information on AAC audio options, please refer to this MeWiki page
or this Wikipedia entry
Alternative AC3 method:
Follow these steps only if you plan to use AC3 audio in your file. Select "FFMPEG AC-3" for "Codec" and press the "Config" button. The codec configuration window should show up.
Ensure "Output Channels" is set to use "Keep Original Channels". You can adjust the bitrate to use - 384 kbps is the minimum used by commercial DVD AC3 5.1 tracks, while many use 448 kbps for extra quality. You can press the "New" button and save the current profile (eg. name it "AC3 5.1, 384 kbps") for future use if you wish. Press "OK" to close the codec configuration window.
Now proceed to the next step/page.