[MEncoder-users] Important News for iPod/iPhone/Quicktime Encoding

[James Hastings-Trew]

  On 10-06-29 5:16 AM, - wrote:
> iPod and iPhone OS 4, and possibly Apple's new Quicktime X, can no longer
> handle ANY B frames in h264 mp4 videos. [?]
>
>   This is CONTRARY to recent mencoder documentation that many of you will
> have.
>
> This may apply for other MPEG-4 standards, but I haven't tried them yet.
> Seems stupid that they should wander further from the specifications with an
> upgrade, but there it is-over-priced proprietry software. So, unfortunately,
> file sizes will increase a bit.
Video files destined for the Apple TV, ipod, ipod touch, iphone, and 
ipad have never tolerated b-frames. They also use a fairly low-spec idc 
level of 3.1. AFAIK this has not changed. These devices are low-power, 
low-memory devices. More "expensive" encoder tricks such as CABAC, 
b-frames, and mixed reference frames all require more memory, and are 
inappropriate for devices of this kind. Every video I have encoded for 
Apple equipment still plays fine after the update to IOS 4.

Quicktime X on my iMac (which has plenty of power and memory) is 
completely different - it will play anything I care to throw at it, 
including video destined for higher profile devices such as the Sony 
PS3, which uses idc level 4, and 3 b-frames.