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Is there any difference between an I-frame, intra frame, inter frame, and key frame.

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Edwin Street
Is there any difference between an I-frame, intra frame, inter frame, and key frame.
on Oct 5, 2012 at 2:34:39 pm

Each have their own wikipedia page but is there any real difference between these four types of frame?

I'm using Compressor 4 to burn a DVD and under encoding settings it gives me the option to set Key frame every so many seconds. Is this an I-frame?

I thought an I-frame stands for intra-frame, then what is an inter frame, and why call it a key frame?

I-frame:
http://en.wikipedia.org/wiki/Video_compression_picture_types

Intra-frame:
http://en.wikipedia.org/wiki/Intra_frame

Inter frame:
http://en.wikipedia.org/wiki/Inter_frame

Key frame:
http://en.wikipedia.org/wiki/Key_frame


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Sareesh Sudhakaran
Re: Is there any difference between an I-frame, intra frame, inter frame, and key frame.
on Oct 6, 2012 at 8:40:15 am

Intraframe or I-frame compresses each image/frame without considering the images that precede or follow it. E.g. If a video has a frame rate of 24 fps, then each frame is compressed separately.

On the other hand interframe codecs choose a certain 'set' of frames and uses 'similar' information from subsequent frames to further compress data. Examples are MPEG-2/DVD, h.264, etc. Simply put, the main frame in each set is the key frame.

If every frame is a key frame, then you have an intraframe codec!

All things being equal, intraframe is better than interframe. On the other hand, interframe codecs are smaller in size, hence are used almost exclusively in consumer video channels like DVDs, blu-ray, Internet, broadcast tv, etc.

For more detailed info, try my explanation Here. Hope this helps.

http://www.wolfcrow.com - Workflow information and support for filmmakers, photographers, audiographers and videographers.


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igor jovcevski
Re: Is there any difference between an I-frame, intra frame, inter frame, and key frame.
on Oct 6, 2012 at 9:41:20 am

and don't forget , quality doesnt have to do nothing with a footage being intra or inter. its more to do with editing convenience. Some inter frame codecs have superior quality and extremely small sizes. then you got the a b frames...

Igor
Woowave.com
tools for digital artists


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