• Blackmagic Design

  Online Jpeg codec data rate

  Posted by Paul Spurrier on September 8, 2007 at 8:48 am

  I’m just coding a piece of HD video 1920 x 1080 using the MJPEG codec new with the Decklink update.

  Firstly I was a bit confused, because it’s referred to in documnetation as the Online JPEG codec, but it seems to appear on the computer options as the MJPEG codec.

  But what is concerning me is the low data rate. It seems to be coming out at roughly 5.7Mb/second.
  Now admittedly this is a cinemascope picture, and so at the top and bottom of the 16×9 frame there is a black border. I suppose this might reduce the data rate. But even so, this seems very little, and I’m worried that somehow I’ve got it set wrong – although I was not actually given any choices of settings.

  I’m worried that the quality of my output when delivered may not be what I hope it might be.

  Can anyone tell me what sort of data rate they would expect. Nowhere in the Decklink information is this mentioned.

  Thanks.

  Paul

  Margus Voll replied 18 years, 8 months ago 2 Members · 1 Reply
• 1 Reply

• 

  Margus Voll

  September 9, 2007 at 7:12 am

  Hi.

  It is normal to get about up to 10x lower rate than with uncompressed if i do not imagine stuff here :). I use it all the time and works perfectly. This MJPG JPG i think differs from pc to mac as i.Link and FireWire but the inner stuff is the same i think. So if the data rate is about 2x times DV rate then it is fine i guess. What i like is that MJPG still gives you 4:2:2. I hope i got my facts right here.

  —

  Margus

  https://iconstudios.eu

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