Whilst I'm aware that within Quicktime Pro it is easy to export a file for AppleTV, I am curious exactly what codecs and specific settings are a) playable and b) optimum for the highest picture & audio quality on both a second and third generation Apple TV respectively. As a professional video editor I'd like to be able to manually control my encoding settings to ensure that I am pushing the hardware of these AppleTVs to their maximum to deliver the highest bitrate and quality available. I am also curious, if I encode a clip as 1080P for a generation 3 AppleTV, will the same clip be playable on a generation 2 AppleTV, albeit at downrezzed 720P, or will the AppleTV require a separate 720P encoded version to work? Also, what forms of surround sound are supported by AppleTV? Thanks for any help.
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Encoding settings for Apple TV (Gen 2 & 3)
- Thread starter andboom
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Ill try to answer your questions one by one as best I can.
Settings playable are the same as the High @ 4.0 h.264 profile settings. This is outlined as:
Max resolution: 1920x1080 @ 30 FPS
Max Bitrate: 25,000 kbps
The optimal settings I have found are:
Resolution: 1920x1080 @ 23.396 FPS
Bitrate: 19,000 kbps video / 640kbps AC3 Audio
More than that seems to cause some slight lag every once and a while and stuttering during high bitrate scenes. I recommend using a 2-pass VBR encode for this process (The CQ function in handbrake also works very well, but I like doing 2-pass as it helps keep files under a certain size).
The 2nd Gen Apple TV can also play these files, and iTunes will automatically downmix them to 720p, however higher bitrate files will require a high end processor to reduce stuttering.
The Apple TV itself supports AAC 2-channel files ONLY. If you do AAC 6-channel it will downmix it to a weird 3.0 audio as I learned from Dynaflash and verified with a file played on my surround sound system.
If you put a 6-channel AC3 file, the Apple TV can pass-through these files to your receiver and your receiver will decode properly if it supports AC3 decoding (most after 2005 or so will do this without a problem). To do this, you must set the audio settings in the Apple TV to support this.
You do this by going to Settings -> Audio and Video -> Dolby Digital -> ON (not auto).
I hope this answers your questions. Also keep in mind it is best to have 2 audio tracks, the primary being the 2-channel AAC, the secondary being the 6-channel AC3. This will allow universal support to all iPhones and iPads using the A4 processor and newer.