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Old Dec 5, 2013, 4:14 PM   #1
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Default Please explain 'qualities' in 1080i

I recently purchased a Panasonic HC-920M digital video camera (top pro-sumer model) and started taking video with the default camera settings which included 1080i (interlaced) HG (quality) which I found later to be not the top quality selectable.

I am assuming that the different 'qualities' affect how much COMPRESSION is used to record the video as using a lower 'quality' results in smaller file sizes - is this correct?

Can this ALSO affect -
sharpness and/or
contrast

or does it only affect how much 'noise' is recorded in the picture?

Thanks

John
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Old Dec 5, 2013, 5:45 PM   #2
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You are correct that the quality setting determines how much the video is compressed. More compression gives smaller file sizes and also affects all the factors you mention. The most noticeable is the 'noise' or artifacts produced, but you also lose detail, sharpness, contrast and color saturation with more compression.
If you have the option of 720p, with less compression, you may end up with better video for a given file size. You just have to take some time to experiment.

brian
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Old Dec 5, 2013, 7:16 PM   #3
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Thanks Brian for the quick reply.
I did change the settings to 1080p (which has no 'quality' settings) 2 weeks into my trip after posting a question to to 'friends' at the Corel Videostudio forum.
Being a brand new camera I didn't give it a thought.

I have started to edit the video taken and have only worked with the clips taken at 1080i HG and was disappointed with the clarity (sharpness and contrast). I had viewed some clips taken with the same camera on Youtube before purchasing the camera and was very impressed and thought my video should be as good.
So (it seems) when I 'get to' the clips recorded at 1080p I should be happier.

BTW regarding recording in low light. With my old Panasonic GS400 (mini DVI tapes) I used to record low lit scenes in manual mode setting the GAIN to a low value and then brightening during editing to reduce 'noise'.

My Panasonic HC-X920M obviously records differently and so should it be 'better' recording low lit scenes with less (gain) noise?
I remember watching a youtube clip recorded by the light of car headlights and didn't see any 'noise' yet the clip was very sharp.
Should my new camera record low lit scenes using 'gain' (up) with less (picture) noise

Thanks

John

Last edited by jparnold; Dec 8, 2013 at 1:23 AM. Reason: add text
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Old Dec 30, 2013, 12:36 PM   #4
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i = interlaced
p = progressive

progressive scan basicly means it puts in extra lines into each rotation of the scan on screen. Therefore a smoother image/more fluid.
So 1080i and 1080p will still be the same resolution and quality. Just 1080p should look/run smoother.
This is also why some will prefer 720p over 1080i. People just prefer the fluid motion over the pixel detail quality. And the file size will be smaller ofcourse, and capture quicker, which MAY reduce noise.
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Old Dec 30, 2013, 4:09 PM   #5
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Progressive does not mean any extra lines are included. It scans the lines in numerical sequence, 1,2,3,4, etc.
Interlaced scan uses the sequence 1,3,5,7, etc., then returns for 2,4,6,8, etc. This paints the picture on the screen faster. Interlaced scan was used originally in television for several reasons, including lower bandwidth requirement.
The reason the videos using interlaced scan tend to be less crisp looking, is that there can be noticeable movement between the first half (the odd number lines) of the frame, and the second half (even numbers), resulting in blur.

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Old Dec 30, 2013, 4:42 PM   #6
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Thanks for the information.
I must say though that at this time I am a little disappointed in the results so far using my new Panasonic X920 video camera.
I have not got the same results as video I found shot with the same camera on Youtube eg http://www.youtube.com/watch?v=TEW2PARMbRo
I get nowhere near the sharpness in this video clip when using 1080i 'standard' quality (I realised later that there were settings for higher quality but considered that this might only affect 'compression' when recording to memory similar to the effect with compression with JPEG images).
Cam anyone explain what the 'quality' settings affect? Is it basically how much compression is used and if so can that affect contrast and/or sharpness?

Last edited by jparnold; Dec 30, 2013 at 4:44 PM. Reason: change link
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Old Jan 21, 2014, 5:04 AM   #7
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Quote:
Originally Posted by LAngelo View Post
progressive scan basicly means it puts in extra lines into each rotation of the scan on screen. Therefore a smoother image/more fluid.
You know what, i dont even know why i wrote that,
i even know its wrong <facepalm>

Like above, the all lines are rendered on the same pass.
What i ment to say i think, is that with p, as well as the linear pass,
you can have individual lines refreshed out of the pass.
That is what also gives the smoother image quality.

en.wikipedia.org/wiki/Progressive_scan
Or just google progressive scan.
There's loads of imagery around as well, that might help you understand how its actually working
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