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Author Topic: Image Quality Degradation Using DVD Medium  (Read 6248 times)

Kit-V

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Image Quality Degradation Using DVD Medium
« on: September 02, 2012, 08:57:15 am »

Although my question is a color management issue, please let me know if it would be more appropriate to move my discussion to the Beginners' Questions forum.

My problem is the loss of image quality on still photos that have been burned to DVD-R. Let me elaborate a bit. I process RAW images in Abobe Lightroom 4 on my MacBook Pro running OS 10.7.4. From there, they are exported to FotoMagico 4 (public beta version) for creation into a slideshow. To this point, image quality has been acceptably retained. Next the completed slideshow is exported from FotoMagico to iDVD for burning to disk. Subsequently, the image quality of the slideshow photos on DVD are considerably degraded. Specifically, there is a dramatic loss of sharpness, loss of vibrancy & overexposure.

 Is this an inherent problem of burning high-resolution photos to a low-resolution medium (i.e. the DVD disk)? I understand that a DVD is limited to a 720 X 480 pixel resolution for NTSC format. Or is this a problem with iDVD? Or is my workflow missing something?

 My goal is to create a high-quality slideshow with audio track & transitions that can be shared with others. Thank you for any help you can provide. I truly appreciate & respect the advice of the participants in this forum.

Kit
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Simon Garrett

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Re: Image Quality Degradation Using DVD Medium
« Reply #1 on: September 02, 2012, 09:33:52 am »

Low resolution is not an inherent problem of DVDs.  However, it is a problem of NTSC format.  I'm not familiar with Fotomagic or iDVD, but if they insist on NTSC format, then that's a problem!

If you need to be able to play it on a standard DVD player to a DVD then I guess you're limited to NTSC (or PAL if you're in Europe).  The alternative would be if you have a BluRay DVD recorder (and people playing the DVD have Bluray players and HD TVs), in which case you can record in HD format (1920x1080).  Of course, if the DVDs are going to be viewed on PCs, then no need to stick to TV format, and you can store in as high resolution as you like, if the DVD-burning software you are using supports it. 
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Kit-V

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Re: Image Quality Degradation Using DVD Medium
« Reply #2 on: September 02, 2012, 09:54:12 am »

Simon:  Thank you for the prompt response. If I can summarize your point:  Poor image quality of still photos burned onto a DVD is not a problem of the DVD medium per se; rather a problem of the photos being burned in the NTSC format as opposed to the HD format. Thus, if I am able to burn the DVD in HD format (I.e. 1920 X 1080 pixels), image quality should not be degraded. Am I correct?

If so, I will see whether this is a viable option for me. Again, thank you.

Kit
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Simon Garrett

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Re: Image Quality Degradation Using DVD Medium
« Reply #3 on: September 02, 2012, 11:17:17 am »

Yes, but to expand slightly:

DVDs can store data in several ways.  The main ones:
  • Video to be displayed on a TV.  This can only be NTSC (for the US).  BluRay DVDs also handle HD, provided you have a BluRay recorder, and a BluRay player to play them back.
  • Computer files to be read on a computer.  You can store any file on this format, and images can be stored in any resolution.  Basically, this type of DVD can be read on a computer.  DVD players (the sort you connect to a TV) can sometimes read them, but usually not.  Just to confuse matters, you can also write computer files in this way on a BluRay disk (if you have the appropriate BluRay writer on the computer), but that just makes them bigger (they store more data) - you can still write any type of file to them.   

Normally the whole DVD is written in video format or computer file format. 

So if you are creating a slide show that writes to the DVD in video format, and plays as a video on a TV, then you're limited to NTSC resolution on a normal DVD, or HD on a BluRay. 

If your slide show program creates the slide show in a normal computer file, and it's going to be written to a DVD in compute file format, then it can be any resolution, provided the program creating the slide show supports it, and you're going to play it back on a computer (or you have a DVD player that can cope with that type of file connected to the TV - as I say, most TV DVD players don't). 

However, I don't know anything about Fotomagic or iDVD (or Macs, for that matter) so I may be giving you incomplete and misleading information!  With luck, and expert on those will be around soon to give more info. 
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Kit-V

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Re: Image Quality Degradation Using DVD Medium
« Reply #4 on: September 02, 2012, 12:07:08 pm »

Simon: I really appreciate the detailed response. Your explanation is very clear. Since my forte is photography (as opposed to output presentation), this is a good learning process for me.

Thus, I can infer from your comments that outputing my images in the form of a high image-quality slideshow on a DVD for display on an HDTV screen is likely not a viable option. Thus, is it reasonable to assume that the best alternative might be displaying the slideshow directly from the slideshow-creation app (in my case, FotoMagico) by connecting my MacBook Pro directly to either a HDTV or a projector?

Thank you for your patience.

Kit
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Simon Garrett

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Re: Image Quality Degradation Using DVD Medium
« Reply #5 on: September 02, 2012, 12:45:56 pm »

Given I'm no expert in Mac software, I think a bit of reading of the software help might be good here, or hope for a Mac expert to turn up here!
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Kit-V

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Re: Image Quality Degradation Using DVD Medium
« Reply #6 on: September 02, 2012, 01:09:15 pm »

FYI, I ran the slideshow directly from FotoMagico by connecting the MacBook Pro to a HDTV. Problem resolved. Image quality was not degraded. So for the time being, I will bypass burning to DVD & consider this as my slideshow presentation medium.

But I am looking forward to other thoughts & opinions on this issue since using a DVD would be more convenient for me.

Thank you, Simon, for your help!

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Simon J.A. Simpson

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Re: Image Quality Degradation Using DVD Medium
« Reply #7 on: September 06, 2012, 02:29:07 pm »

Another Simon answers !

I am a Mac user and have encountered similar difficulties when trying to create a slideshow.

The problem is with the way the Mac software (in your case iDVD) encodes the slideshow into a video.  Basically iDVD and the other Mac software that comes with OSX use various compression routines, one of which is to only encode every other scanning line.  Thus for UK TV (PAL) 625 lines are the normal resolution (I'm simplifying this a bit) but the Mac video encoding software removes half the lines (so encodes only 312½ lines), thus the soft results.  The same applies using the NTSC standard.  I found this out by lengthy research on the internet.

How did I get around this ?
After a lot of experimenting and testing I found that the best way was to make the slideshow from iPhoto, this retains the full resolution of the original.

In your case, if you need to get the slideshow onto a DVD, you will need to consider some other DVD creation software.  This is where my knowledge is exhausted but researching the internet would bring some useful results.  I don't know if Roxio's Toast will work better ?

I hope this helps.
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Kit-V

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Re: Image Quality Degradation Using DVD Medium
« Reply #8 on: September 06, 2012, 09:32:42 pm »

Thank you, "another Simon". I also have gleaned the same information while researching my question. Your point regarding using iPhoto is well-taken. However, several years ago I transitioned from iPhoto to Lightroom. I needed the extra post-processing capabilities & organizational structure as my photography skills improved.

Similarly, I moved from iMovie to FotoMagico. Nevertheless, your point is still valid. Thus, it appears that my best option (as far as the retention of image quality is concerned) is to run my slideshows directly from FotoMagico. My 2nd-best option is to export the slideshows to FotoMagico's  StandAlone Player (accessible to Mac users only).

Although exporting to QuickTime Movie might be an acceptable option, I need to explore this more.
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Mac Mahon

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Re: Image Quality Degradation Using DVD Medium
« Reply #9 on: September 07, 2012, 04:35:26 pm »

Hi
I run a Mac and have just experienced all this same frustration in trying to prepare a slide show for an exhibition. 

I too prepared a very acceptable quality slide show in Fotomagico, but all my attempts to reproduce the slide show in DVD format ended up with lousy sharpness loss and poor colour etc.  I tried iDVD, Quicktime and Roxio Toast all with the same results.  Leaving my laptop hooked up to the TV Monitor at the exhibition was not an option.

The answer we came up with was particularly simple.  It turned out that the TV monitor we were playing on has a USB input, and inbuilt slide show software. All I had to do was export the images as an ordered set of JPEGs* at 1080 size, onto a USB flash drive; stick it in the TV, and negotiate the built in menus!  It worked very well:  images at very acceptable quality.  Needless to say I lost the transition effects and other bells and whistles that make Fotomagico shows a bit different, but hey, the show worked.

Cheers

Tim

I made 'em all sRGB in the absence of any information at all about the colour characteristics of the TV - so there's a bit of compromise there.
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