Sorry for not being clear. The Last Kingdom started "on time" in terms of the beginning of the program. What I meant was that two programs were scheduled for 21:00 so this could have been an explanation for one program starting recording 4s late in relation to the broadcast. But the Channel 4 HD program start was already 2m later than the BBC Two HD one so this was no excuse for the box to start the second recording late.
The remaining two programs:
Code:
Date/time Channel Title Start Stop # EPG Blocks Synopsis
--------------------- ------------ ---------------------------------- ---------------- ------------------------------- ------------ -------------------------
Fri 27 Nov 2015 00:35 BBC Four HD Detectorists On time, logo Complete but before next logo 1 Correct
Fri 27 Nov 2015 21:00 BBC Two HD Great Continental Railway Journeys On time, logo On time, next logo 1 Correct
Summary: 1 recording out of 8 started late (albeit only by 4s but still late), which in my view is a failure rate of 12.5%, not very impressive. No recording stopped early. This is still a lot better from what I saw some days ago, where most started late. I'll schedule some more test programs on weekday afternoons and keep an eye on these.
A tad confused, how can you expect a lossy delivery system that the smallest time interval you can resolve is in the number of frames compressed into a group of pictures (GOP) to be accurate to the degree you expect. To make digital TV possible requires lossy mpeg compression, Basically you have a single frame (an I frame), followed by subsequent data that records the difference to the iframe, that allows the subsequent frames within the to be rebuilt (P frames). The higher the bitrate the less video information is lost in the compression process.
Lets compare the average bitrate used by the BBC for HD (which arguably have the best current HD encoders), and are able to share the available bitrate depending on content (rapid movement requires a higher bitrate because the more difference there are between frames needs more data to identify the difference. (A static image (like a photograph has no difference so is very easy to compress).
BBC -HD uses about 7Mbps for it's HD service. In rough terms that's about 7/8 Megabytes/Second. (One byte is 8 bits). One hour of BBC HD would require roughly 3150 Megabytes of hard disk storage (approx. 3.15 GB which is very close to the actual storage requirement).
Now to the actual data that is output from the HDMI socket to your TV.
You have a display that has 1920 x 1080 pixels, each one requires three separate colour information data, 8 bits each for Red, Green and Blue (24 bits in total) 24 bits for each pixel. HDR 4K displays use 10 bit pixels).
That equates to more than 64 million colour combinations.
The data rate required to transmit the amount of data to produce a uncompressed 25 frames/second picture in HD is 1920 x 1080 (pixels) x 24 (Bits/pixel) x 25 (frames/second), which is about 1240 Mbps. Work out for yourself how much of the original digital data is left.
Basically the message is you cannot resolve a mpeg compressed transmission any higher than the basic GOP length without any sort of consideration of the other factors involved.
In the end AR works just fine for me. Why anyone would want any more accuracy baffles me,
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