Different type of MP4's

[Kilau]

Can anyone tell me it these is a "standard" for (iPad *.mp4) versus (PSP *.mp4) versus (H.264 MP4 *.mp4) versus(MPEG-4 MP4 *.mp4) and if so maybe provide a comparision of them or a link to a comparision.

I understand that MP4 is a container (like AVI) and inside the video may be encoded using different codecs (like MPEG2, H.264, etc) but I keep seeing different profiles for MP4s based on the device the file will be viewed on without changing the codec.

My best guess is the different profiles apply different maximum bitrates and difference resolutions, but I can't seem to locate any documention that shows the differences between the profiles. Or is it prehaps because there is no set standard for devices like iPad, iPhone, PSP, or youtube and the different profiles are set based on what the person who wrote the program "thinks" are best for the devices?

Any thoughts?

[Baldrick]

H264 levels http://en.wikipedia.org/wiki/H.264/MPEG-4_AVC#Levels


But then have all devices different kinds of limits....

[Kilau]

Thanks the levels were the answer.

I saved a small clip over and over again all using H.264 and the various "profiles". Using MediaInfo I was unable to look at the Format profile and each one gives a match to the levels your link pointed out.

I guess the people who write the conversion programs and the editing programs pick a level that gets as close is possible (without going over) to the limits of the device (iPad, PSP, iPhone, Droid).

I