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Re: [videoblogging] Re: 720 x 400

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  • Mike Meiser
    ... 640 is not the max width for video. The max size of video for the ipod is based on the total number of pixels. More specifically it s the total number of
    Message 1 of 4 , Apr 27, 2008
      On Tue, Jan 8, 2008 at 6:10 PM, Bill Cammack <billcammack@...> wrote:
      > That would be interesting.... Like a way to avoid scaling from 640 or
      > something. I'm not familiar with, say Tivo frams sizes enought to
      > know why 720x400 might be beneficial.
      >
      > That might just be the case...

      640 is not the max width for video.

      The max size of video for the ipod is based on the total number of
      pixels. More specifically it's the total number of "pixelblocks" which
      are either 16x16 pixels or 32x32 (I can't remember) or 307,200 pixels.

      This is to complex to explain in marketing though so generally
      speaking apple doesn't generally quote it in marketing materials
      though you might find it in a tech document.

      It works out to something like 640x640 or 720x360 (standard DVD
      resolution) or 700x400. You could even go 2000 x 100 though I haven't
      tried it.

      Secondly it's based on codec. The above is for mpeg4 only. H264
      compression/decompression is much more hardware intensive. h264
      videos must be lower resolution and must have a lower bitrate.

      I don't do much h264. In fact I avoid it. So I'm not sure what the
      total number of pixels can be on h264. Generally it's something like
      640x480.

      As for max bitrate, total for video AND audio; 2500kps for mp4, 1500
      max bit rate for h.264.

      My suggetion, is go download iSquint at isquint.com and do some short
      recompression tests using the "advanced" feature. It states right
      there in the side bar the mac bitrate and pixels. Experiment a little.
      Like I said, I've compressed / recompressed stuff to mp4 a lot, but I
      haven't played with h264 compression.

      -Mike
      mmeiser.com/blog

      >
      > --- In videoblogging@yahoogroups.com, "miglsd27" <miglsd@...> wrote:
      > >
      > >
      > > Maybe it makes a difference if you´re plugging the iPod to a TV?
      > >
      > > Miguel.
      > >
      > > > ok... So checking out the http://GeekBrief.tv formats, I became aware
      > > > yesterday that iPods will play 720x400 video. I just checked this out
      > > > on my iPod Nano, and it works perfectly.
      > > >
      > > > The question is if anyone sees a value for this? Personally, my
      > > > column on my website accommodates video 640 pixels wide. The iPods
      > > > are 640 wide or less. If you choose "iPhone" for encoding video in
      > > > quicktime, it makes a 480 pixel wide file.
      > > >
      > > > It seems to me that unless your site accommodates 720 pixel wide
      > > > video, you're better off using the same data rate for fewer pixels,
      > > > meaning hopefully more quality... Especially if you're aiming @ iTunes
      > > > and iPods.
      > > >
      > > > Opinions?
      > > >
      > > > --
      > > > Bill Cammack
      > > > BillCammack.com
      > > > ReelSolid.TV
      > > >
      > >
      >
      >
      >
      >
      >
      > Yahoo! Groups Links
      >
      >
      >
      >
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