5 Replies Latest reply on Jul 9, 2009 4:22 PM by MarkWeiss

    BLU-RAY  DETERIORATION

    Tim Flippance Level 1

      Four Blu-Ray discs of HDV at 40mbps which I burned 2 months ago, and left in a room exposed to daylight (but not direct sunlight), now no longer play (the player says "disc is incompatible"), but 2 identical discs stored in a dark place play perfectly well. A disc at 15mbps left in the light does play.

       

      It would appear that the light has damaged the data on the discs?  Has anyone had similar experiences? Are BR discs known to deteriorate if left in daylight?

       

      These discs were in plastic cases which, though not light proof, shielded them from most of the light.

        • 1. Re: BLU-RAY  DETERIORATION
          MarkWeiss Level 1

          I have no data to support that, but I did discover last week that the life expectency of BD-RE media is about 11 burn/erase cycles before disc playback becomes severely-degraded.

           

          I also experienced a DVD-R going bad just from being left in the player for 30-40 hours, looping the menu animation. After that, inserting the disc results in "cannot play this disc" in my Sony BDP-S301. However, my Pioneer DV343 could still recognize this disc.

           

          Dye is not as stable as we were led to believe. Store in a dry, dark place is still the best policy for archiving. Playing the discs deteriorates them!

          • 2. Re: BLU-RAY  DETERIORATION
            Thrill Media Level 2

            Wow!  That's freaky!  I thought they were much more stable than that.  I was planning on using them as an archive source once I finally get my HD camera.  Did you check the originals once you burned them?

            • 3. Re: BLU-RAY  DETERIORATION
              MarkWeiss Level 1

              Definately! I'd been playing the disc over and over for several days, demonstrating to clients. After about a week, right after leaving it in the player for 2 nights powered on and looping the menu, I tried to play it for another client and it stuttered and froze. So I ejected the disc and reloaded it and ever since that day, the particular DVD always comes up "cannot play this disc" when inserted in the Sony BDP-S301.

               

              This event really changed my attitude about archival media. These technologies work on ever increasingly tighter tolerances. Dye stability is a factor. And the ironic thing about my disc that went bad over the course of continuous playing for a few days, is that the media are listed as archival grade for government and medical use!

              • 4. Re: BLU-RAY  DETERIORATION
                Tim Flippance Level 1

                My BR discs were not re-writable discs, they were the record once variety.

                 

                I once left an ordinary home-burned audio CD in bright sunlight for a whole day as a test, and it was undamaged which is amazing! What can a tiny lazer beam hitting it for about 100nS do which 8 hours of ultra violet and visible light cannot do?

                • 5. Re: BLU-RAY  DETERIORATION
                  MarkWeiss Level 1

                  Just because a disc still plays after exposure to sunlight does not mean it's undamaged. The degradation may still fall within the error correction capabilities of the player, so go unnoticed. But a bit error rate test of the disc would reveal the level of deterioration. The folks at one of the CD information sites ran tests on burns at various record speeds and used a utility to read out the bit error rate for various brands of media at various record speeds. They concluded that burning some discs at lower speed produced better bit error scores (faster read times).

                   

                  In my case, the Sony player must be intolerant of degraded discs. My Pioneer know no difference and still plays that disc, but never more for the Sony.