Generation loss

05.06.2010 13:56

There's an interesting series of videos up at YouTube that nicely demonstrates generation loss in digital video.

Contrary to popular belief digital video and audio do suffer from quality loss when being transcoded from one form into another. These videos give a concrete example of the magnitude of this effect in practice.

The exact details on the codecs used are missing unfortunately. I was surprised how audio seemed to suffer much more than video - even after 1000 copies the basic shapes can still be recognized on the video, while the sound bears no resemblance to the original. It looks like the video codec was simply better at extracting and preserving important information in the stream.

Compare this with generation loss on VHS. Especially note the order of magnitude involved - VHS breaks down after "just" 20 copies. However here audio track is more resilient than video. Not surprising, considering how the data is written on the tape. The audio track also nicely demonstrates the falling signal to noise ratio.

Also, judging by this, most instructional videos we watched in high school were at least 8th generation copies.

Posted by Tomaž | Categories: Life

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