1080p, 720p, 1080i, 480p: Understanding the Numbers


You must have seen these numbers referring to quality of laptop screens, TVs or monitors.  You might argue associating these numbers with video quality as well. Oh, wait did you also see these numbers written on a digital camera? The numbers are indeed confusing.  So an easy to read yet technical description on these numbers  –  just read ahead!

The letters suffixing the these numbers. The i in ‘1080i’ stands for ‘Interlaced’.   Have a look at the pictures below:




The 2 parts of the same picture:








A word of caution before we proceed – I’ll be talking in terms of  ‘Video Quality’  first. There is the original picture – P1.  Pictures P2 and P3 are say the blocks of a puzzle which combines to form p1.    If the  pictures P2 and P3 are flipped at a very high frequency, the human eye cannot distinguish if these where two different pictures at all  and what you see is a single picture as in picture 1.  But a video is not a single image. Right, a video is a collection of pictures flipping at a very high rate.When you pause a video you get some still image on your screen. The image that was being projected was a combination of two pictures as I showed above. So at any point in the video, only half the picture is being projected, which is obviously being flipped so fast that you can’t make out. To get a bleak idea on how it may feel – save these pictures in a new folder and then change them using the arrow keys in Windows Picture Viewer.

You can also compare interlaced projection to painting a picture – with odd lines painted first followed by the even lines.

Now for the letter ‘p’. ‘p’ stands for ‘Progressive’.  As the names suggests pictures are progressively flipped in such type of a video. Unlike an interlaced projection where virtually only half of the image is screened at any point of time in progressive projection complete pictures are screened.

So you may  think, obviously the progressive is a better quality any day.  A full picture being flipped is obviously better than a half. I recommend you to read ahead before you make a decision.

Now for the numbers. We can’t leave the numbers behind in our discussion of progressive and interlaced projections. 1080 corresponds to the resolution of 1,920×1,080 pixels or 1080 lines of vertical resolution. 720p stands for  1280 x 720 pixels or 720 pixels of vertical resolution. So 1080i would mean a resolution of 1920×1080 pixels being projected in a interlaced manner and 1080p would mean the same resolution being progressively projected. Now we can safely say that 1080p is a better quality projection than 1080i. But there is ambiguity over the 720p projection. Some say that the 1080i quality is better than the 720p while others believe that progressive projection improves video quality and hence 720p is better than 1080i. However 1080i is definitely better than 420p. Even though 420p is progressively projected – the resolution is very low with just 640×480 pixels.

Talking in terms of the displays – the TV’s, the computer monitors and in terms of the pictures that are clicked by modern day digital cameras. As I mentioned 1080 is equivalent to 1920x 1080 pixels, but your screen should support that resolution to display such high quality. So if your screen supports that kind of resolution you’ll find it labelled HD Display or HDTV for a TV. (There are other factors determining if a display is HD or not – but we leave that discussion of frequencies and bandwidths for this post). Even if your display is not HD capable it does plays the HD videos or display HD Pictures. That’s where referring the quality in terms of lines of resolution comes into play. Your picture or video may have a resolution of 1080/720/480 vertical lines with no consideration of the display it will be projected on. The quality of the output is retained irrespective of the display.  You’ll feel the difference between the quality of the videos of different on most screens (barring the CRT displays – again a long explanation on why).

You might like calling these numbers with some special names:

High Definition or HD for 1080p.
Standard Definition for 720p. Also called HD in 720p.
Enhanced Definition for 480p.

My take on content quality is  1080p>720p ≈1080i>480p.  I hope you find this information helpful for your next ‘Gadget Shopping’!


The making of Treasure Hunt


20 Teams register. Some calculations showed we’ll be able to manage 15 of them. Elimination Round was all we needed to filter the teams out. First Day of Treasure Hunt and huge response! People were really excited about the first of it’s kind activity being held at the college. On stake were one thousand bucks.

What kind of questions for the Elimination Round of a ‘Treasure Hunt’ thats supposed to be a ‘IT (Information Technology) Event’? Some of my previous experience, got me to put anagrams on the quiz sheet. The dictionary defines the anagrams as a word or phrase formed by reordering the letters of another word or phrase, such as satin to stain. That’s got something to do with cryptography. One reason the event was being organized by the IT Cell and was deemed a “Technical Treasure Hunt”.

Looking for more information on cryptography? Here wikipedia has lot’s of it.

Everything goes fine. People just love solving the anagrams, and the list cuts to just 15 teams.

But here we have the Challenge # 1. Finalizing a date for the finals. No classes can be cancelled, and people won’t like to stay for too long after 4. What do we do? More over there are Lab Viva’s and tests in between. Then there is the Second Test that’s coming up. But finally we get a date. One day 2 hours. Shouldn’t that be enough. Wait I didn’t tell you what  exactly had to be done?

The contestants have to decode clues. Clues that point to a location in the campus. Reach that location and answer another question and also complete a task. An IT Task. Yes, something like programming.

That brings me to Challenge #2. Since this event was being organized by the IT Cell, it had to be related to IT. Rs. 1000 won’t come easy.  Preparing the C questions was actually not a challenge. But  convincing people was. But thanks to the co-operative friends, there were no revolts on the inclusion of the easy programs.

Seemed all set. The clues were ready a month before. The treasure hunt team held several meetings and brainstorming sessions of how we could prevent people using unfair means. How could the system be fool-proof. But how were we going to communicate the clues? We thought that we’d SMS the clues. SMS the clues through mobile phones? No. Through the internet (way2sms.com). Sounded cool.  Messages being sent through internet, and received on the phone. People had to communicate with us, through the mobile phone.  All ready for the final day…

Managing the Teams. Challenge #3. As I just mentioned, all just “seemed” perfect. Did you think 15 teams was too much for a small campus? If yes, you were right. These 15 teams weren’t the school teams I had seen and organized events with at computer symposiums. These were a team of first year college students. Let me tell you these were actually 15*2 = 30 people in all. Okay now picture this. 30 people , right before me, “excited and enthusiastic”. An un-explainable situation.  The Treasure hunt was being organized really professionally. We had the control room. The computer room actually, which was locked for the participants.

System Failure. Challenge #4. Cool ideas are cool enough only when they work. The much talked about messaging system failed just at the right time. How do we send the messages now? No problems, we had people with message packs on some qwerty keyboard phones. So now the mobiles took over. By the time we couldn’t even message everybody,  we started getting replies. Replies giving answers, asking for hints. And there were people constantly banging at the door who hadn’t yet received the message! We had the message packs and so did the participants. So these were not single messages from a team, it was multiple messages.

Tension Inside. Fun Outside. Challenge #5. As all this happened, we were falling short of time. As things were going out of control inside the control room, everybody started to panic. So we decided to call the teams one by one inside our secretive room  to give clues and “settle scores”! Meanwhile, people were having enormous fun outside. There was full on cheating (though it drowned some teams), the clues were a fun to solve , there was running around, all for the first time ever on a usually boring college day. So it was indirectly a successful day for us. Though now we needed another day to continue, with the treasure hunt.  And luckily we managed to get this quickly. We now had just 10 teams competing for the final spot.

Success Finally. We learned from our mistakes. We abolished the messaging system. Every round now became an elimination round. After the first round we eliminated 2 teams and thereafter eliminated half of the total teams every round.  From 8 to 4, 4 to2 and finally the winners. How did we do that?  The order of the events changed to:

1. Find a output to a C program.

2. Whoever finishes first gets a location clue, and runs to the location and take the picture.

3. Teams that return back first, get selected. For rounds where half of the teams were eliminated, we introduced competition between 2  teams by giving the same clues.

Here’s what the winners Tarun and Anuraag had to say (text in pic below):

Winners Word Winner's Word

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Annexure A. The treasure hunt clues and solutions.

Annexure B. The Elimination Round

P.S. You may use the clues and questions for your own treasure hunt. Don’t forget to see the licence details on your right though!

Special Thanks to the Treasure Hunt Team. Puneet, Abhikul, Vaibhav, Ashutosh, Nikhil and Tushar. (Random Order)
And to my friend from the times of school, Mridul for troubleshooting and new ideas.

iPhone: Myths and Facts


Myth: You can not forward messages on an iPhone.
Fact: With the launch of iPhone OS 3.0 (free update for all iPhone users), you can forward messages on an iPhone. All new iPhones come pre installed with the OS 3.0 or above.

Myth: No Cut, Copy Paste on iPhone.
Fact: You can cut, copy and paste text and pictures on iPhone.

Myth: You can not share photos through Bluetooth.
Fact: The receiving device must be compatible to do that, iPhone can transfer photos through Bluetooth.

Myth: Updating iPhone is a tedious task.
Fact: Updating iPhone is very easy. Just connect your iPhone to iTunes and the rest is done. Updating iPhone your not only adds new features but also improves battery life.

Myth: iPhone battery don’t last even a day on standby.
Fact: Tested. iPhone batteries last at least 2 days on stand by. (Push Notifications disabled).

Myth: You can not listen to music, while working on the other apps.
Fact: Absolutely wrong. You can minimize the iPod app and work on the other apps. Double tapping the Home button even shows the control buttons, without disturbing the current application.

Myth: iPhone touch screens are too clumsy to type.
Fact: Thanks to the great touch screen interface of iPhone, it ignores unwanted touch gestures and the typing experience is at par with the other touch phones.

Myth:You have to get one of the speakers of iPhone unlocked.
Fact: This is the weirdest rumor I have heard. The other speaker looking inlet on the bottom right of the iPhone is actually the microphone.

Myth: You cannot transfer files from your  PC to an iPhone.
Fact: There are several free applications on the Apple App Store that allow you to transfer files on your iPhone wirelessly.

Myth: There is no POP3 support for Windows LIVE accounts/hotmail  email accounts.
Fact: False. There is support for all popular e-mail service providers including Windows LIVE accounts. In fact there are no constraints on configuring POP3 accounts on iPhone.

Based on my experience with people talking about the iPhone. Would love if  you could add more to the list!

P.S. I am a big Apple Fan. 😛