{"id":384,"date":"2009-01-20T21:23:12","date_gmt":"2009-01-20T10:23:12","guid":{"rendered":"http:\/\/hifi-writer.com\/wpblog\/?p=384"},"modified":"2010-01-28T15:48:48","modified_gmt":"2010-01-28T04:48:48","slug":"miss-potter-shall-be-amongst-my-most-played-blu-ray-discs","status":"publish","type":"post","link":"http:\/\/hifi-writer.com\/wpblog\/?p=384","title":{"rendered":"Miss Potter<\/em> shall be amongst my most-played Blu-ray discs"},"content":{"rendered":"

In an earlier post<\/a> I noted that the newly released Blu-ray of Miss Potter<\/em><\/a> runs at 25 frames per second, rather than the usual 24. So it appears to have been sped up, for no good reason. I made reference to it being ‘the first Blu-ray movie I had seen which was not recorded at 1080p24, but at 1080p25.’ A couple of days later Craig Mecak, a tech wiz at Channel 9 in Sydney, corrected me on this point:<\/p>\n

From my research, 1080\/25p is not a valid blu-ray resolution\/format.Allowable combinations are:<\/p>\n

1080\/24p
\n1080\/50i & 60i (actually 59.94i)<\/p>\n

720\/24p
\n720\/50p & 60p (actually 59.94p)<\/p>\n

Suspiciously absent are 1080\/25p or 1080\/30p. Not really a big issue, as I’m sure you’re aware that 1080\/25p can losslessly be conveyed as 1080\/50i, whereby each field contains half the number of lines from each original film frame. In effect, it’s 1080\/25Psf (progressive segmented frame).<\/p>\n

Deinterlace back to 25p by weaving the fields. Simple.<\/p>\n

<\/span><\/p><\/blockquote>\n

I’m prepared to take Craig’s word for this; he really does know a lot about this stuff. At the time I replied to that effect, and I agree that it is odd that 1080p25 and 1080p30 weren’t provided for in the Blu-ray specification. Still, perhaps they were worried about chipset availability or some such.<\/p>\n

I was tied up for a while so it wasn’t until last night that I actually watched this movie. I must say it is a charming little movie. But of principal interest here is the picture quality. Watching fairly closely and using an actual TV for once instead of a front projector (it was the forthcoming Pioneer PDP-C509A 50 inch plasma, $5,499), at several points in the movie two things were obvious: Craig was right, and the Blu-ray player wasn’t doing a very good job.<\/p>\n

In those scenes in which almost horizontal diagonal lines were moving across the screen, the jaggies were obvious. Which means that, first, even though the material originated on a progressive source (it was shot on film), it was encoded on the disc at 1080i50, not 1080p25. That meant that the Blu-ray player had to deinterlace it.<\/p>\n

As Craig says, it should be a simple matter of weaving the two fields back together to restore perfect 1080p25 picture quality. But the Blu-ray player was doing a shockingly poor job at deinterlacing, not just those jaggie bits but also, I think, the whole movie. It certainly seemed a lot softer on screen than I expected. At this stage, I am thinking that the player was doing drop field deinterlacing. But I shall explore further.<\/p>\n

Meanwhile, I now have a Blu-ray disc I can use for testing 1080i50 deinterlacing of progressive-sourced material, just too late for a set of five low cost Blu-ray player reviews I completed a few weeks ago, but just in time for set of five expensive Blu-ray player reviews I shall soon be starting.<\/p>\n","protected":false},"excerpt":{"rendered":"

In an earlier post I noted that the newly released Blu-ray of Miss Potter runs at 25 frames per second, rather than the usual 24. So it appears to have been sped up, for no good reason. I made reference … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[3,4,24],"tags":[],"_links":{"self":[{"href":"http:\/\/hifi-writer.com\/wpblog\/index.php?rest_route=\/wp\/v2\/posts\/384"}],"collection":[{"href":"http:\/\/hifi-writer.com\/wpblog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/hifi-writer.com\/wpblog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/hifi-writer.com\/wpblog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/hifi-writer.com\/wpblog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=384"}],"version-history":[{"count":1,"href":"http:\/\/hifi-writer.com\/wpblog\/index.php?rest_route=\/wp\/v2\/posts\/384\/revisions"}],"predecessor-version":[{"id":385,"href":"http:\/\/hifi-writer.com\/wpblog\/index.php?rest_route=\/wp\/v2\/posts\/384\/revisions\/385"}],"wp:attachment":[{"href":"http:\/\/hifi-writer.com\/wpblog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=384"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/hifi-writer.com\/wpblog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=384"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/hifi-writer.com\/wpblog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=384"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}