HD MiniDV tape capture looks grainy? (HDV)
 

I recently started transferring my HD DV tapes to PC using a Sony HVR-M15U through a 4-9 pin firewire. The video during transfer is grainy and no different during playback. when played through composite cable from the deck to HDTV, image is amazing. is it because of HD format that it looks weird on a regular monitor? or does it have something to do with refresh rate of the monitor?

edit: maybe not grainy, but griddy?

Possibly, yes.

Composite is around 640x480 max resolution (arguably even less), so you're not seeing the 100% HD resolution. And as you seem to understand, old TVs and connection methods hide HD noise. I'm still amused by all the HDTV ads promising clearer pictures from the 2000s, but all it really did was reveal how bad SD images looked. Or how bad homemade HD looked. (Not to mention most "HD" home stuff is not really true HD because of the sensors, glass, etc.)

The Firewire transfer method is not altering the image in any way. The only possible issue would be if the "capturing" software (not really capturing, but transferring) is doing anything to the image. However, I doubt it. It probably really is just grainy HD footage.

Where was it shot? Indoors? Low light?

It was shot using a canon HV10 dv camcorder onto Sony DVM-63HD tapes and transferred using scenaliyzer through a firewire card using one of the Texas instruments chipsets. it was shot indoors and out in good light, but the gridiness doesn't change. maybe i should post a frame to see what im saying.

As I recall, the HV10 shot HDV video (1440x1080i) and DV (720x480i).

The composite output has it downscaled to 480i and the horizontal reolution is limited by the composite signal and Y/C separation in the viewing system to perhaps 330 or so video lines. It may end up much less depending on the composite signal quality of player and the TV - but that may not be all bad for viewing purposes. (Analog SD video often looks nicest when viewed on a good old tube TV that tends to hide the warts in the signal.)

The grain in the footage is probably due to variations in individual pixel sensitivity and dark current, and it becomes more apparent with increased gain, use of slower shutter speeds, and low contrast, flat scenes.

The downscaling and conversion to analog output tends to "filter" or "average out" out some of the grain not unlike applying a blur filter to the HDV footage.

Software products like NeatVideo can be used to reduce visible grain and noise.

The HV10 is going to have some grain to the video, its sensor noise. My HV20 has a similar look to its video, particularly indoors.

noise eats bitrate. bitrate equals quality. downscaling eats quality.

the hv10/20 have rather small lenses with an average cmos sensor size. low light/indoors will definitely have grain.

i would suggest installing VLC and taking a screenshot or two where the noise is most prevalent.

Here are a few of those screen shots. maybe grainy is the wrong term?:question:

Thank you

Doesn't look like anything out of the ordinary from what I can see, but the files have been resized smaller than the native video. HDV output should be 1920x1080. Plenty of interlacing artifacts. You have to deinterlace if you want to shrink the video.

Also you want to turn off in-camera DV transcoding. The camcorder has a function that will convert the firewire output from HDV to standard defintion DV on the fly. See page 35 of the HV10 manual and make sure the camcorder is not in "DV Locked" mode.

HDV output is usually a MPEG-2 transport stream (.m2t), not DV.

+1 - I am not sure that you even resized purposefully, the photos are from a widescreen DV source. HDV should be 1440x1080 stretched to full 1080i

I am transferring from a Sony HVR-M15U deck. I am 100% it was recorded in HD. I just realized the down converting is done by the deck(i-link) and just found the option to turn it off, but now with i-link off, scenalyzer doesn't see any input device anymore. I am using the sd-pex30009 firewire card.

Do you have the camera directly hooked up to the card?

The interlace artifacts (zig-zag vertical edges) will appear in any captured HDV (or DV) frame (not field) that has a horizontal motion component.

HDV from the HV10 is 1440x1080 with non-square pixels. From recollection the HV10 had two internal menu settings that had to be correct for HDV (or DV for that matter) output via firewire. However, I do not know if that applies to the Sony you mentioned as well.

I don't know about scenalyzer, but some capture software has to be set to the source format before it will recognize and capture input video.