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Video Quality in Recording direct to computer through mini recorder vs onto SD card

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Kaiwen Li
Video Quality in Recording direct to computer through mini recorder vs onto SD card
on Dec 15, 2014 at 3:35:13 pm

So what blackmagic is saying is that when you're capturing, you're bypassing video compression and you can get higher quality video than recording onto cards, which makes sense, especially if you recording uncompressed, the file size is gigantic. But after testing out the same footage captured live and the other pulled from the SD card, I find the opposite is true. After bringing up the contrast and brightness, it seems that footage from the card is better, even if the size of the captured video is 100 times large than the SD card footage. So what is the deal here? Am I doing something wrong or is it a misconception that capturing through hdmi is no better than recording into SD card?

Thanks a lot!


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Russ Froze
Re: Video Quality in Recording direct to computer through mini recorder vs onto SD card
on Dec 15, 2014 at 8:53:15 pm

The file on the sd card will probably be 8 bit. When recording to via HDMI the file will be recorded at 10 bit unless the camera outputs 8 bit via HDMI out. There should be a lot more information in the colors, no banding etc. If your camera has a 10 bit HDMI out.
Russ Froze


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Kaiwen Li
Re: Video Quality in Recording direct to computer through mini recorder vs onto SD card
on Dec 15, 2014 at 11:07:44 pm

Yeah I see. But how do I find out if my camera's hdmi outputs 10 bit or 8 bit?
Thanks!


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Russ Froze
Re: Video Quality in Recording direct to computer through mini recorder vs onto SD card
on Dec 16, 2014 at 9:05:49 am

Well there's the rub isn't it. Those clever little wordsmiths in the communications department have done it again. The truth is that even if your camera has an 8 bit output the external recorder will record at 8 bit 4:2:2 whereas the sd card is most likely to record 8 bit 4:2:0. So technically there is a gain in the color space so the claim of improved recording is true, technically.

Now as to what the camera signal out is. That is a question many would love to get a straight answer to. Until recent camera releases where manufacturers have stated and proven the hdmi out. There has been a reluctance to come up with a straight answer. The short story is that up to recent releases consumer and prosumer cameras with hdmi out were meant to be viewed on 8 bit interlaced monitors and or TV sets. Most but not all cameras adhere to this so it comes down to the model number. Fist thing to assess is if the camera output is 29.796 progressive or 59.976 interlaced. If it is 59.976 I or 60I it is unlikely to be a 10 bit signal. Now I state unlikely. I have to put this in as a disclaimer for the debate will be rekindled and I wish to stay out of it. If the output is of a progressive nature there is a chance it may be a 10 bit signal. Again I state that it may be.

The only way I know for sure is to plug the camera in question into my field monitor and let it hunt for the signal and look at the settings when a connection has been made. That is the only advice I have to offer, find someone who has a field monitor that accepts all the signals and take it from there. If any one else has a suggestion(s) please share the info.
Russ Froze


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