The terms DAP (Digital Audio Player) and PMP (Portable Media Player) are often used randomly regardless of whether or not the player in question only plays audio or if it does other media. With today’s technology the majority of players over a certain size support video and pictures so these terms naturally get more and more merged.
The thing many people don’t realize with video capable players however is that video isn’t just video. The quality and usability the end user receives depend on two things; the screen and the video formats supported. Some players have so bad media support that they shouldn’t be allowed to advertise PMP functionality and resolution is a major player in this game. Read on for the breakdown of screen resolution on PMPs.
To show how much difference there is from one example, I’ve taken two screenshots from TV shows – one 16:9 and one 4:3 show. Below each resolution’s description are these screenshots resized to the screen resolution (click the thumbs for full size), both with the aspect ratio intact and stretched (which is either of the two screenshots depending on whether it’s a 4:3 or 16:9 resolution). It should be fairly obvious which ones are stretched, so I’ve not marked them.
128×160/160×128 (iAudio U3, F2, X5, Creative Mozaic+++)
Technically 160×128 is a 5:4 aspect ratio but it’s close enough to 4:3 to let go. The reason for that is that this is basically the worst resolution a video player can possible have in 2008, with 128×1288 players going out. Players with this resolution shouldn’t be alowev to advertise video and picture support, the resolution is simply to useless. Screen sizes are normally around 1.8-2″ for this resolution, which gives 20480 pixels. That’s about 10000 pixels per inch, which is 1/3 what’s normal. Although these players are sometimes highscreens, videos are watched widescreen so thats what the screens are based off
176×220/220×176 (Sandisk Sansa e200, Sansa Fuze ++)
This is a resolution often used by SanDisk, and it’s still long away from being a decent video resolution. 176×220 gives you 38720, which with 2″ screens give us 19360 pixels per inch, 4:3 aspect ratio. Twice the number of pixels and pixel density of the 128×160 players, but still far away from the standard in that screen range.
320×240 (Cowon D2, Creative Zen, Sony NWZ Video Players ++++++)
This is an extremely common resolution and also the first one that’s worth watching anything on and so this resolution should be what separates DAPs and PMPs regardless of whether or not smaller players can play media. 320×240 aka QVGA (Quarter VGA) equals 76800 pixels, with 30720 pixels per inch on a 2.5″ screen, 4:3 aspect ratio. Most screens this resolution is 2.5″ but some are lower (Sony S610 is 1.8″, Sony A810 is 2″, Clix 2 is 2.2″, Archos 405 is 3.5″ etc). While some think this resolution and screen size is also too low, people with normal vision should be able to watch an occasional movie on it. I wouldn’t recommend going too much over 2.5″ without stepping up resolution wise at it will bring down your pixel per inch count and it will be noticeable, especially on players such as the Archos 5.
480×272 (Samsung P2, PSP, Zen Vision:W, iAudio A2, O2, S9++)
For a long time this was the standard for big harddrive based PMPs, which now normally use 800×480 instead. With a common screen size of 4.3″, 480×272 aka WQVGA (Wide Quarter VGA) gives you 130560 pixels at 30360 pixels per inch, 16:9 aspect ratio. This is about the same pixel per inch count as 2.5″ 320×240 screens with double the actual number of pixels. The new Cowon O2 and S9 will both use this resolution, but while the 4.3″ screen of the O2 is rather normal the 3.3″ screen of the S9 will give you a much higher pixel per inch count – 39563. The Samsung P2 has the same resolution on 3″, which means 43520 pixels per inch. The pixel per inch count is important because it will give you a much more natural looking picture with less visible pixels, but higher pixel per inch count on a set screen size means higher resolution which again means you need a higher bitrate to keep the quality up and that in term gives you higher file sizes.
For example, the Cowon O2 and Cowon A3 have the same physical screen size but the A3′s resolution is 2.5 times bigger. That means more pixels per inch, which means more detailed image. The higher resolution however requires higher bitrate to compensate and that gives you larger files. As commenter coreying pointed out, you can also turn it around and look at it from a perspective with a set resolution and variable physical screen size: The Samsung P2 vs the O2 has more pixels per inch because it’s only 3″ vs the 4.3″ of the O2 with same resolution. If you were to play the same video file on both, you’d be more picky about the quality on the O2 because the pixels are bigger and it’s easier to see if something’s off. Thus one can argue that you’d need higher bitrate also if the PPI is lower because you see the quality difference better than on a smaller screen with more piels per inch. It all depends on wheter or not the physical screen size or the resolution is the fixed value when you compare.
800×480 (Archos 605, 705, 5, 7, Cowon A3, Q5+++)
This is the holy grail of screen resolutions on a PMP. 800×480 aka WVGA (Wide VGA) gives you a whopping 384000 pixels with a 16:9 aspect ratio, about 2.5 times that of 480×272. With a common screen size ranging from 4.3″ t
o 7″ this gives you anywhere from 89302 to 54857 pixels per inch. This resolution is bigger than DVD resolution and your biggest problem with this resolution will be finding material that will use the entire resolution. The new generation 5 series of Archos players including the Archos 5 will use this resolution and in terms with older Archos players this huge resolution can be put to good use with a web browser.
There are other factors that have a say to screen quality besides resolution. The number of colors is the most common and is often given in the specs. The early cell phone screens were 4096 colors, and since then we’ve been through 65000 colors, 256000 colors and up to 16.4 million colors. This does make a difference, but might also be a marketing tool – the ability to display a lot of colors doesn’t mean it does it well. For instance, the Cowon D2 and Sony PSP both have 16.4 million colors but the D2 looks so much better it’s almost frightening.
The screen type itself also matters when looking for screen quality. More and more players use AMOLED screens, a technology where the pixels light up and you don’t need a backlight like you do with LCD. Less power consumption, more battery life – and these screens are also very bright and generally good.
Furthermore you have the distance between pixels on a screen. 320×240 doesn’t look good on a 2.5″ screen if you can see the space in between pixels, which on some low quality screens you can. Viewing angle is also a problem on some players, where the screen is unwatchable from a certain angle. The Cowon D2 is known to have a problem with this when tilting the player with the top slightly towards you. These issues aren’t something you see in specs so the best option is to test a player before buying if you’re concerned – reviews and feedback will almost always touch on such issues if there are any.
I could confuse people more and go on about interlacing and whatnot – something there’s been a lot of talk about lately with the new PSP Bright – but it would serve no purpose. Lot of less known factors help decide the end result, but it’s not something consumers can easily find out. My advice is: Look for screen resolution, then number of colors and read reviews to see real life experiences with the screens in case of issues like bad viewing angle. Last but not least, don’t ignore video formats – something we’ll come back to later.