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View Full Version : AVCHD in cam vs. Prores HQ capture via HDMI



cheezweezl
06-03-2011, 06:10 PM
So while I am waiting to figure out which external recorder to buy, I decided to see what the visual difference even is between AVCHD and Prores HQ. So I shot to the card and captured to the mac at the same time via HDMI.

Settings: 1080/24P FX. HDMI output was set to 1080i. I captured into FCP at 1080i/59.94 Prores HQ. After capture I removed the pulldown using cinema tools. I captured the AVCHD from the camera via log and transfer and transcoded to Prores HQ, leaving me with two almost identical files. The only difference is length as I had to manually hit record on the cam and capture now on the mac.

I focussed on my hand about a foot from the lens and waved my two hands across the screen rapidly to give both codecs a workout.

Watching on a 42" plasma, I really couldn't see a difference. However, looking at individual frames, i could see it every time. The AVCHD tends to soften details when taxed with moving objects. At it's worst (on my example) I saw banding and blotches of color. I picked out one of the nastier frames as an example. I exported directly from the FCP timeline in JPG format. I used the highest quality and bit depth to minimize the jpeg compression. The stills here look identical to what I see on my screen in FCP. Below the pics are links to the full size 1920x1080 stills, which show quite a bit of difference between the two.

AVCHD in cam

https://files.me.com/fisherfilmworks/fkb50f

Prores HQ via HDMI

https://files.me.com/fisherfilmworks/m9gvdq

AVCHD in cam (full size) (https://files.me.com/fisherfilmworks/6pbhpt)

Prores HQ via HDMI (full size) (https://files.me.com/fisherfilmworks/e8sjob)

rgdfilms
06-03-2011, 07:08 PM
It looks like you're getting about 1/2 stop more latitude when going out of the HDMI

cheezweezl
06-03-2011, 07:16 PM
speaking of latitude, there was a question of whether cinetone 1 allows highlights greater than 100. it most certainly does. i just shot some outside footage and clipping doesn't occur until 110. i have my pic profile set up with slightly elevated black levels to +5. i notice that blacks are clipping at 5 but it's a much softer clip than i would expect. i don't know if the raised black levels are doing it or not but me likey.