iPod touch video support

I have tried the following video types that work in the iPod touch

• Container format: MOV or MP4 (files should be renamed to .M4V)
  • Video Codec: MPEG-4 Video (mp4v): 623x352 @ 384-512 kbps works!
  • Audio Codec: MPEG-4 AAC LC (mp4a): 96-128kbps stereo works!

(Read more about formats at Apple)

Even though the native resolution is 480×320 the ipod can scale the media to the best ratio.

Transcoding

VLC media player allows 1-pass transcoding from/to different formats, to create an iPod compatible video transcoding a source.avi to dest.m4v you might want to set:

• height to 320 pixels (the source should be taller than that)
• audio bitrate to 128kbps stereo
• video bitrate to 512kbps (not nice but good enough, 768kbps seems to be a much more near perfect result).

The transcoding can be done by command line:

vlc 
 file:///source.avi
 :sout=#transcode{vcodec=mp4v,height=320,vb=512,acodec=mpga,ab=128,channels=2}
 :duplicate{dst=std{access=file,mux=mp4,url="c:dest.m4v"}} vlc:quit

mpeg pixelation

While transcoding some mpeg files the output is made of huge pixels (don't know the reason yet) but can be fixed by adding a frames per second (fps) to the transcode instruction.

I tried some different fps and it seems that over 24 my eyes could not notice the difference (I believe the ipod screen is kind of slow compared to normal pc monitors)

vlc 
 file:///source.mpg
 :sout=#transcode{fps=28,vcodec=mp4v,height=320,vb=512,acodec=mpga,ab=128,channels=2}
 :duplicate{dst=std{access=file,mux=mp4,url="c:dest.m4v"}}

About iTunes

Drag and drop files

ITunes seemed to be very delicate about file names, I can drag and drop .mov files directly into the ipod (not passing through the library) as long as they do not contain .avi also in the file name:

• clip.mov Ok!
• clip.avi.mov Not Ok!

Invalid resolution issue

even though transcoding allows you to change the output size, mov and mpeg files have a resolution stated that may differ from the actual movie, so even though the movie is 480x320, the "recommended" resolution is still higher than 640x480, with wich iTunes will refuse to copy the file to the iPod.