[mythtv-users] nuxexport - export to iPod
kichigai at comcast.net
Sun Jan 29 02:54:34 UTC 2006
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On Jan 28, 2006, at 20.40, Matt wrote:
> I'm excited to see that some of the iPod settings have been put into
> nuvexport. However, it's disabled because it says "Your ffmpeg
> installation doesn't support encoding to mov file formats." I've
> configured ffmpeg to build with x264, isn't that the proper format?
> Any other ideas?
x264 is just the codec pack. It doesn't include anything on the
container. You might want to look into mp4box.
> Also, I wanted to add this... just because I think it could be
> relavent to making sure that anything encoded for the video iPod meets
> the correct standards:
> Apple publicly says that the iPod has the following video limitations:
> H.264 MPEG-4
> Maximum Resolution 320x240 480x480
> Maximum Bitrate 768 kbps 2500 kbps
> Maximum Framerate 30 fps 30 fps
> However, the company has actually simplified the iPod's real
> limitations to make them easier for people to understand. Many users
> have discovered that while the bitrate limits above appear to be
> absolute, the resolutions are not. Rather, they observed that the
> equivalent number of total pixels appeared to be the practical limit
> for both H.264 and MPEG-4 - 76,800 and 230,400, respectively. Like
> Apple's own numbers, these pixel limits are useful and simple ways to
> make sure your files run properly, but these numbers are not
> technically correct, either.
> Rather, the correct limit can be stated as follows:
> For H.264, you're allowed 300 square blocks of pixels (called
> "macroblocks"), 16 pixels on a side. For MPEG-4, you're allowed 900.
> The widely-published "total pixel limits" for H.264 and MPEG-4 will
> indeed work in most cases, but not always, and macroblocks yield the
> right numbers. For example, an MPEG-4 video of dimensions 725 x 315
> has less than 230,400 pixels, but 920 macroblocks. Such a file would
> be incompatible with the iPod.
> For reference, here are a few resolutions that satisfy the maximum
> macroblock limits at various video aspect ratios:
> 320x240 - ideal
> 480x480 -ideal
> mythtv-users mailing list
> mythtv-users at mythtv.org
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