Video formats
I have a few (easy?) related questions.
I have a video (VHS, European PAL) camera and am interested in converting the films to digital format. Some questions in general.
The video format VHS, what is the resolution (width x height) and frame rate?
mpg1 and mpg2 digital formats. Are they lossy? Would it be better to save the converted film (from VHS) as mpg2 or is that just a waste of time because the original analog format would be of low resolution so mpg1 suffices?
I have a video (VHS, European PAL) camera and am interested in converting the films to digital format. Some questions in general.
The video format VHS, what is the resolution (width x height) and frame rate?
mpg1 and mpg2 digital formats. Are they lossy? Would it be better to save the converted film (from VHS) as mpg2 or is that just a waste of time because the original analog format would be of low resolution so mpg1 suffices?
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By example, Pinnacle Systems' Digital Video Creator 120 (DVC 120) has 720x576 capability with hardware encoding. It is a high quality home system.
Have a look to: http://www.pinnaclesys.com/
For reference pricing:
http://www.tigerdirect.com/applications/searchtools/item-Details.asp?EdpNo=931737&sku=P121-8056
Have a look to: http://www.pinnaclesys.com/
For reference pricing:
http://www.tigerdirect.com/applications/searchtools/item-Details.asp?EdpNo=931737&sku=P121-8056
Some extra commercial link a bit nearer:
http://www.pinnaclestore.ch/shop/assets/s2dmain.html?http://www.pinnaclestore.ch/shop/50142195050c65e3a/
http://www.pinnaclestore.ch/shop/assets/s2dmain.html?http://www.pinnaclestore.ch/shop/50142195050c65e3a/
ASKER
Hi Jaime
Thanks for the links (I have just purchased a pinnacle AV/DV system because I require input from an analog device).
Graphics isn't my strong point (to put it mildy) and I am trying to stay afloat in the flood of information. Actually it is also to get information independant from the manufacturers of the hardware.
To recap, I am getting the picture form a VHS camera (200 lines - khyer123). Would 720x576 actually offer any advantage over 352x576 ?
It's late in the evening here, I'm off to get some sleep now (providing the kids allow - the eldest has a cold). Hopefully my brain is functional tomorrow!
Thanks for the links (I have just purchased a pinnacle AV/DV system because I require input from an analog device).
Graphics isn't my strong point (to put it mildy) and I am trying to stay afloat in the flood of information. Actually it is also to get information independant from the manufacturers of the hardware.
To recap, I am getting the picture form a VHS camera (200 lines - khyer123). Would 720x576 actually offer any advantage over 352x576 ?
It's late in the evening here, I'm off to get some sleep now (providing the kids allow - the eldest has a cold). Hopefully my brain is functional tomorrow!
Actually VHS has a low line scan resolution, as khyer123 mentioned, but some other sources like HI8 and DV cameras have 400 and more scan lines, so, it is a good idea to have a 720x576 device.
About horizontal resolution, it is virtually infinite in analog video sources, contersense vertical resolution which is limited to scan lines, so I think 720x576 could bring you a better quality, just try, but as I mentioned, it will depend in your specific hardware.
To have a hardware capable of 720x576 doesn't means that you will achive more quality necessarily, depending on internal filters and ADCs of the device.
About horizontal resolution, it is virtually infinite in analog video sources, contersense vertical resolution which is limited to scan lines, so I think 720x576 could bring you a better quality, just try, but as I mentioned, it will depend in your specific hardware.
To have a hardware capable of 720x576 doesn't means that you will achive more quality necessarily, depending on internal filters and ADCs of the device.
hi andy,
hope your project is progressing :)
the settings i proposed are meant as a starting point. if you find that another setting gives you better results, please use it :)
what has worked for me is to capture the source material at full resolution (720x576 in your case), and compress further from there (using either 720x576 or 352x576)
it seems logical to me that the higher resolution will give you a better result.
it's easier to recompress if you're unhappy witht the result than to recapture the video again
the target bitrate is lower than what you calculated because the object is to compress the video to make it fit in an svcd. if you were saving to dvd you can allow yourself a much higher bitrate. i should have asked you if this was your goal before proposing these values.
also, i haven't calculated bitrates manually for a long time (i can't even find my old references!). but here is a bitrate calculator to help you decide what bitrate to start at:
http://www.videohelp.com/calc.htm
vbr is variable bit rate. it distributes the available bitrate differently amongst the frames of your movie, giving more bitrate to the portions of the video that have lots of movement and changes (so higher quality) than the parts of the video that are more static (because they need less bitrate to look fine). the idea is to get a higher quality video without using more bitrate.
the oposite is cbr (constant bit rate). this allocates each frame exactly the same amout of bitrate. this is normally used for web video (in my experience anyhow)
hope i'm not being too confusing.
hope your project is progressing :)
the settings i proposed are meant as a starting point. if you find that another setting gives you better results, please use it :)
what has worked for me is to capture the source material at full resolution (720x576 in your case), and compress further from there (using either 720x576 or 352x576)
it seems logical to me that the higher resolution will give you a better result.
it's easier to recompress if you're unhappy witht the result than to recapture the video again
the target bitrate is lower than what you calculated because the object is to compress the video to make it fit in an svcd. if you were saving to dvd you can allow yourself a much higher bitrate. i should have asked you if this was your goal before proposing these values.
also, i haven't calculated bitrates manually for a long time (i can't even find my old references!). but here is a bitrate calculator to help you decide what bitrate to start at:
http://www.videohelp.com/calc.htm
vbr is variable bit rate. it distributes the available bitrate differently amongst the frames of your movie, giving more bitrate to the portions of the video that have lots of movement and changes (so higher quality) than the parts of the video that are more static (because they need less bitrate to look fine). the idea is to get a higher quality video without using more bitrate.
the oposite is cbr (constant bit rate). this allocates each frame exactly the same amout of bitrate. this is normally used for web video (in my experience anyhow)
hope i'm not being too confusing.
also,
when you say digital format: do you mean just a file saved in your computer? or is the final goal to save it to a dvd, svcd? or a mini DV tape? the target media influences the type of compression you'll use.
best regards,
daniel.
when you say digital format: do you mean just a file saved in your computer? or is the final goal to save it to a dvd, svcd? or a mini DV tape? the target media influences the type of compression you'll use.
best regards,
daniel.
ASKER
Sorry for the delay in responding.
Am I correct - the lower the bitrate for a given resolution, the higher the compression / the more lossy the compression?
The situation.
I have a video camera (VHS) and a number of tapes of my children. Everytime a tape is played the quality will deteriorate. I have relatives/godparents in another country who wish to see the kids growing up so it is nice to be able to send them a copy and not worry about an original being lost/damaged.
The idea.
Digitise the tapes and store on a hard disk(s) (keeping the original VHS tape just in case). Then I can burn one or more copy to CD (no DVD burner) and send CD through post. The digital copies will probably not be edited (else I would catch as AVI, edit then digitise to an mpg format).
I do appreciate that the higher the bitrate/resolution the less information is lost but also the more space on staorage medium is required. Also at some point the law of diminishing returns comes in. Ten times the size for 1% quality gain....
I guess the answer to a number of points is try it and see if it is OK.
I am still puzzled by the 'width' of VHS. Is the height (scan lines) set in a standard but the width variable - device dependant?
Am I correct - the lower the bitrate for a given resolution, the higher the compression / the more lossy the compression?
The situation.
I have a video camera (VHS) and a number of tapes of my children. Everytime a tape is played the quality will deteriorate. I have relatives/godparents in another country who wish to see the kids growing up so it is nice to be able to send them a copy and not worry about an original being lost/damaged.
The idea.
Digitise the tapes and store on a hard disk(s) (keeping the original VHS tape just in case). Then I can burn one or more copy to CD (no DVD burner) and send CD through post. The digital copies will probably not be edited (else I would catch as AVI, edit then digitise to an mpg format).
I do appreciate that the higher the bitrate/resolution the less information is lost but also the more space on staorage medium is required. Also at some point the law of diminishing returns comes in. Ten times the size for 1% quality gain....
I guess the answer to a number of points is try it and see if it is OK.
I am still puzzled by the 'width' of VHS. Is the height (scan lines) set in a standard but the width variable - device dependant?
Yes, that is correct.
VHS doesn't have a dimension. NTSC does, and that's what folks in the US are using. Your capture software should take care of it for you or at least give you some options to choose from.
VHS doesn't have a dimension. NTSC does, and that's what folks in the US are using. Your capture software should take care of it for you or at least give you some options to choose from.
ASKER
daniel416.
Interesting link, albeit I am no graphics expert it looks to be good.
Your recomendation.
352 X 576, 25 fps 2520 kilobits
How do you get the 2520 KB/s ?
352 * 576 * 25 / 1024 = 4950 which isn't even a multiple of 2520, but not far off.
as the link states: The ratio of bitrate per pixel dictates MPEG image quality.
also what is VBR?