First, let's review the different sorts of surround sound you'll commonly encounter.
HandBrake offers several surround options depending on your uses.
- The simplest method is using Dolby Pro Logic II. This is the default behavior for HandBrake. If you feed HandBrake an Dolby Digital AC3 or Digital Theater System 5.1 sound track and tell it to convert using AAC, it will default to converting or "downmixing" the track to Dolby Pro Logic II in an AAC track. This will sound fine on both stereo and surround audio systems and will play in pretty much anything. If your DVD already contains Dolby Pro Logic audio, also known as Dolby Surround, it will be preserved. If you wish, you can use Dolby Pro Logic I instead of II, by selecting "Dolby Surround" from the Track Mix drop-down menu. Be aware that, due to technical concerns, Dolby Pro Logic II is currently created as 5.0 sound. This means there is no separate subwoofer channel. Adding the sub channel can cause serious distortion, depending on how the DVD's audio was mastered.
- The next method is called pass-through. This just copies, bit-for-bit, the soundtrack on your DVD. AC3 pass-through is possible in the .mkv, and .mp4 containers. DTS pass-through is possible in the .mkv container. QuickTime can decode AC3 audio but cannot pass it audio your optical port for use with a surround sound receiver. However, you can download a 3rd party QuickTime component from the open-source Perian project to achieve this. If you use the .mp4 container, you can pass-through AC3 audio in VLC, Perian, or on the AppleTV, although you have to end the file name in .m4v instead of .mp4 for QuickTime and the AppleTV. Using AC3 in .mp4 this way is standards-based, but it's a new standard and not everyone is on board yet. VLC or Perian can decode DTS audio in .mkv files, but pass-through of DTS is currently broken in Perian. To use pass-through, make sure you have AC3 or DTS Passthru selected in the Audio Codecs pop-up menu.
- You can also combine Pro Logic II and AC3 pass-through. This will give you a file that will play anywhere from QuickTime to VLC to the iPhone (using the AAC Pro Logic II track) and play in true surround sound on an AppleTV or in Perian. It is the best of both worlds, and it is only possible in the .mp4 and .mkv containers. Again, MP4 file names must, confusingly, end in .m4v for QuickTime to read them. To use this hybrid format, in the Audio tab, set the first audio track to be the track you want, in AAC sound. Then set the second track to also use the same source track, and select AC3 pass-through.
- Another method is to create 5.1 channel AAC audio tracks. For the Track Mix, select "5.1 Channels" from the drop-down menu, and your movie will contain discrete surround sound in the modern AAC format. This takes up less space than AC3: instead of 448kbps, you can do well with 384kbps (64 kbps per channel). Its real benefit is that it doesn't make QuickTime barf. Sadly, it is very difficult to hear all those discrete channels of sound. It cannot be sent over an optical cable to a home theater amp. If you try, whether on a Mac or an AppleTV, you will only hear "downmixed" surround sound, similar to Dolby Pro Logic. To hear the discrete surround sound in all its glory, you will need to attach an analog surround sound device to your Mac. One popular device is the Griffin FireWave. Then, you have to attach a cable to your amp/receiver for each of the six speaker channels. It cannot be done over optical/HDMI.