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mariush · 11th October 2014, 23:14

I understand what you're saying but you're wording it incorrectly. Losslessly is the wrong term.

Yes, iPhone may encode the videos it captures with some looser parameters which result in a large file. The phone most likely uses a specialized module in the processor who's only purpose is to encode videos, so that will be optimized to use few resources and as little battery as possible, not to keep the videos small in size.

You could take this content and encode it again with much better parameters and the result will be different (not a lossless recompression) but visually you'll have a hard time noticing anything different and the file size will be smaller.

A lossless code will actually encode a series of pictures and when you play it, the pictures will be 100% identical. If you take a screenshot from the original video and a screenshot from the new video that you encode losslessly, each pixel will be identical. You don't want that or need that.... your eyes won't notice that a few pixels change a bit in one or a few snapshots from a second, when you have 24-60 snapshots in a second of video.

11th October 2014, 23:14	#2 \| Link
mariush Registered User Join Date: Dec 2008 Posts: 589	I understand what you're saying but you're wording it incorrectly. Losslessly is the wrong term. Yes, iPhone may encode the videos it captures with some looser parameters which result in a large file. The phone most likely uses a specialized module in the processor who's only purpose is to encode videos, so that will be optimized to use few resources and as little battery as possible, not to keep the videos small in size. You could take this content and encode it again with much better parameters and the result will be different (not a lossless recompression) but visually you'll have a hard time noticing anything different and the file size will be smaller. A lossless code will actually encode a series of pictures and when you play it, the pictures will be 100% identical. If you take a screenshot from the original video and a screenshot from the new video that you encode losslessly, each pixel will be identical. You don't want that or need that.... your eyes won't notice that a few pixels change a bit in one or a few snapshots from a second, when you have 24-60 snapshots in a second of video. Last edited by mariush; 11th October 2014 at 23:16.