DVD to Apple TV Conversion on Mac: AAC/ AC3/ DTS 5.1 surround sound or Stereo?

There’re discussions and debates concerning Apple TV and 5.1 audio, and everyone has his own opinion. Does the Apple TV support 5.1 audio? What kind of video and audio fits Apple TV best? Is it possible to enjoy surround sound from Apple TV? In this post I’d like to share you something practical and really means: how to choose audio codec and channels when ripping DVD to Apple TV optimized videos.

Dolby Digital 5.1 and DTS 5.1 audio are the most common surround sound in DVD movie clips.  The DVD specification requires that regular movies provide minimally an AC3 (i.e. Dolby Digital) soundtrack, with DTS sound as an option. When backing up DVDs to Apple TV, most folks wish to keep the original 5.1 surround sound. Does Apple TV support Dolby Digital 5.1 or DTS 5.1? Let’s take a brief view of the technical specifications of Apple TV:

 

Video formats supported

• H.264 video up to 720p, 30 frames per second, Main Profile level 3.1 with AAC-LC audio up to 160 Kbps per channel, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats
• MPEG-4 video, up to 2.5 Mbps, 640 by 480 pixels, 30 frames per second, Simple Profile with AAC-LC audio up to 160 Kbps, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats
• Motion JPEG (M-JPEG) up to 35 Mbps, 1280 by 720 pixels, 30 frames per second, audio in ulaw, PCM stereo audio in .avi file format

Audio formats supported

• HE-AAC (V1), AAC (16 to 320 Kbps), protected AAC (from iTunes Store), MP3 (16 to 320 Kbps), MP3 VBR, Audible (formats 2, 3, and 4), Apple Lossless, AIFF, and WAV; Dolby Digital 5.1 surround sound pass-through

From the above description we learn that MP4, MOV, M4V with AAC stereo are naturally supported by Apple TV. And supported 5.1 audio is Dolby Digital 5.1 sound pass through. So what’s the best format for ripping DVD to Apple TV? Well, this depends on the amplifier or AV receiver you use.

Solution 1. If your AV receiver is capable of decoding AAC 5.1…
Most receivers with surround sound decoders only support the older AC3 or DTS 5.1 formats, and can’t directly decode multiple channels delivered in the newer AAC 5.1 format. But AAC 5.1 is strongly recommended when your receiver support AAC 5.1 decoding. AC3 isn't really a good codec for surround sound in movie files because it uses a fixed bit rate. The newer AAC delivers better quality at the same bitrate. With support for AAC 5.1 surround sound, the surround receiver can use it directly from Apple TV.  You can rip DVD to H.264 or MPEG-4 encoded MP4/ MOV/ M4V with AAC audio of 6 channels using Pavtube DVD Ripper and then sync the video to Apple TV via iTunes. Now that your receiver supports AAC 5.1 channels, you can use the Toslink optical port to deliver AAC 5.1 to your receiver in full quality.

Solution 2. If your AV receiver decodes Dolby Digital/ AC3 5.1...
In case that your amplifier/ AV receiver does not decode AAC 5.1, but supports Dolby Digital decoding, you're encourage to convert DVD to H.264/ AC3 encoded MP4/ MOV/ M4V format with Pavtube DVD Ripper (Win & Mac). Note that QuickTime and iTunes can’t play AC3 tracks, so when previewing ripped DVD movie with AC3 audio in Quick Time Player, the video contents play well with no audio at all. Apple TV does not play the AC3 audio itself, but the set is able to output AC3 data over the Toslink optical port to your AV receiver to decode the audio into six channels. The Apple TV decodes video contents and pass through AC3 to your receiver for 5.1 decoding, that's the way you enjoy AC3 surround sound.

Solution 3. If your AV receiver decodes Dolby Surround Pro Logic…
Again you can shrink DVD to H.264 or MPEG-4 encoded MP4/ MOV/ M4V with AAC audio of 6 channels using Pavtube DVD Ripper, and then sync the video to Apple TV via iTunes. The Apple TV does something special with AAC 5.1 audio: it mixes it into Pro Logic so that your receivers can split it into multiple channels of sound, with a separate center channel and front and rear stereo. This is known as 4.0 channels. Apple is using it in its movie downloads and trailers, since almost all the 5.1 receivers support Dolby Surround Pro Logic and the format is backwards compatible with regular stereo equipment as well.

Solution 4. When/ If you do not use a receiver...
In fact, the majority of 5.1 sound on DVDs is played back in regular stereo by end users. For Apple TV users who are getting used to stereo audio, ripping DVD to MP4, MOV or M4V with 2 channel AAC seems a fine idea. In this way you don’t have to add external audio devices to Apple TV, and the AAC stereo is well-supported by QuickTime Player and iTunes. Besides, the ripped Apple TV video also plays great on iPhone 4 and iPad when you rip DVD to 1280*720 or 720*432 MP4, MOV or M4V.

Please also feel free to:
Learn more about the Pavtube DVD Ripper for Mac.
Take a look at a more powerful application, the Pavtube Blu-Ray Ripper for Mac that rips DVD and Blu-ray to Apple TV on Mac OS. 
Find a program to rip DVD to Apple TV with AC3 5.1 track on Windows 7- the Pavtube DVD Ripper for Windows.

For more guides on Apple TV surround sound:
How to put DVD to Apple TV with AAC 5.1/ Stereo audio on Mac?
How to rip DVD to Apple TV with AC3 5.1 audio track on Mac OS X?
How to convert Blu-ray to Apple TV with AC3 5.1 surround sound on Mac?