'her indoors' bought the grand children a new portable DVD player. Now you may ask "what has that got to do with the price of chips?". That means I have to play with it. Pretty impressive, 9 inch LCD, plays DVDs, but it also includes a TV tuner (Analogue only) and it also includes USB memory stick, not at all bad for £25. DVDs are a big thing with the grand kids, we buy the DVD (so they have legal rights to watch it), but they want to watch it on iPhone, Android phone, TV, DVD player etc. So muggins here has to convert.
Conversion is always tricky :-(
Video formats: Basic video contains 2 basic lumps of data, that is sound and video, the 2 need to be in sync, otherwise they look funny, mouth movements don't match voice etc. (this is called lip sync). There is also TONS of this data. Sound is basically just a waveform. Video is usually a sequence of pictures, much like the old cine films, you flash each still up in sequence and you get moving pictures. Problem is the size, take a very small 160 x 120 picture (looks totally pathetic on screen, not worth having), now multiply that up = 160x120=19,200 pixels per picture, consider 16 colour (very low quality, look bad on PC), you need 16 bits (2 bytes) per pixel, multiply that up 19,200x2=38,400 bytes per frame, say 15 frames per second (low frequency, nice is 20, normal is 30), multiply that up 38,400x15=576,000 bytes per second. So you can start to see that the data for a standard 2 or 3 hour film is going to get BIG. So the data is compressed, both the video and the audio are compressed and there are a number of different types of compression that can be used for both, once compressed, these 2 lumps of compressed data are packaged up into a file format (way of storing to USB, Disc, DVD etc.).
The R&D team making the kit knows this well, but the sales, marketing and manual editors are all between them and the customer. What makes it to us is just the file format, what compression types, audio types and video sizes is not mentioned. Video conversion software guys know this, some software will let you convert for a particular mobile phone and that's wonderful, but doesn't work for kit not listed, some list just the formats, then you need to play.
So, I spent the whole of Friday night converting kiddies programs, Grandpa in my Pocket, Mr Tumble, Charlie and Lola. Another thing worth remembering when viewing kids programs, leave logic behind.
Saturday 22 March 2014. Daughter and Grand children staying. Fixed washing line, fixed outside lights. They have a pink Murphy 24 inch flat screen TV, but it has stopped remembering it's channel settings and the DVD is making a loud noise. Pulled it to pieces, nothing obvious, ordered a new main PCB, played the DVD all day, no noise, but by evening it stopped working, motor probably dead, will look at that when I fit the new PCB when it arrives.
Sunday 23 March 2014. Did Roast Chicken, Son, gf, and gf's nephew came over, 5 adults, 3 young children for lunch. The frozen stuffing balls I made worked a treat, cook from frozen, new potatoes fried in Acti-fry, plenty to go around, everyone ate lots.
Got fascinated by Clear ABS. Used it for making the night lights, pretty good as a light diffuser, printed at single layer it's actually almost like smoky glass, but too fragile, 2 layer 0.2 thick is pretty good, started making a clear glasses case out of flexible clear plastic, should look cool.
Monday 24 March 2014. Tenvis Wifi camera arrived (£34 from Amazon), set it up in living room, then sent url, user and pass to daughter in SMS. Lots of belly laughs :-) Wife watching telly, "Hey, that 'thing' is moving on it's own!!!!!", holding a chew for our dog Jack, gets a text "What type of chew is that?", what!!! All a lot of fun, you had to be there. Later it all settled down, sent same SMS to Son. Wife sitting eating a bag of crisps, gets a text "What flavour are they?", wife goes ballistic, really good night.
Tuesday 25 March 2014 (today). Iteratively printing glasses case whilst writing this.
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