Tuesday 18 August, 2009 00:00
On Sunday, I wrote a post about the issues surrounding the use of lossy screen captures of Blu-ray Discs, arguing that there was no real world benefit to using a more space- and bandwidth-heavy lossless format such as .BMP or .PNG rather than lossy JPEGs. I also posted a selection of images and challenged readers to identify which were lossy and which were lossless, promising that I would provide the results on Tuesday.
In case you didn’t see the captures last time round, here they are again:
#1. Monsters, Inc.
#3. The Dark Knight
And now for the results:
- For both Example #1 and 2, Monsters, Inc. and Franklyn respectively, the lossy JPG is Image 2.
- Example #3, The Dark Knight, was a trick question: the actual picture area is identical, neither of them having been saved lossily. In case anyone decided to look at the file sizes and thereby work out that they were both the same, I played around with the black letterbox area on one image, removing some compression guff that was present in the original image, thereby altering its file size.
A few people posted their responses publicly, and a couple more emailed me theirs. Interestingly, no-one got all of them right. One person, who emailed me his answers, got Examples #1 and 2 correct (albeit with the proviso that he was only guessing), but no-one worked out that the two captures from The Dark Knight were the same. The last one was, you might think, a bit sneaky of me, but I never did say I was going to play fair. In any event, I did it to make a serious point: tell people that two images were saved differently, and many will begin to think they see differences, even where there aren’t any.
Well, there you have it. I don’t expect this to put the debate to bed any time soon, but hopefully it provides something of an explanation as to why I not only use JPEGs but also see no problem with doing so.