Please settle a debate re: DV comp.

Yesterday an editor and I were talking about where the 5:1 compression takes place in DV. My answer was "the camera," his was "during the transfer to the computer." So, his claim says that DV tapes have a better picture than we can pull into the computer. (And that repeated copy-to-tape and captures will reduce the quality of an image.)

Who's right?

And along the lines of compression, if DV is always 8 bit, why does exporting a movie from FCP with 8-bit Uncompressed deliver a better quality image than using "current settings"?

Thanks,

Mike

DV is always compressed as it is put onto the tape. Doing a copy from one tape to another has no generation loss. Since it is Digital Video and not analog, the video is copied as 1's and 0's, therefore it can not lose quality on a copy.

8-bit uncompressed is 4:2:2 color space and DV is 4:1:1 color space. Uncompressed is always better quality than compressed. The better use of those 8 bits is what makes the quality better.

The pre-compression inside the camera is how they got all that video (and sound) onto that little-bitty tape.

Vicious pre-compression inside the camera is how they got HiDef (HDV) onto that little-bitty tape.

Koz

Just to squeeze a detail out of you.

Once the DV is 4:1:1 compressed and put into FCP and edited, why does outputting it at 8-bit uncompressed matter? I did a very quick comparison between the same movie output both ways, and 8-bit had fewer artifacts (most visible in the blacks).

And thank you for settling the argument my direction. :-)

If you are rendering FX or Titles, the quality of the graphics is higher. However, the file sizes are much larger and the drives you need to play that back need to be much faster.

If you are doing few FX, you simply stay in the DV codec.



Kevin Monahan
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