Video Playback Quality: Does This Annoy Anyone Else?

[Jason Dunn]

I'm a big <a href="http://www.digitalmediathoughts.com">digital video enthusiast</a>, so I dream in 8000 Kbps data streams. 8) I'm a big stickler for quality, and I'm always pushing the limits on the quality of video playback on mobile devices. So the issue of video quality on the Pocket PC has been bugging me for a long time. I've ignored it/put off testing it for several years, but when I was testing the video playback on the X30 (it's awesome for video!) I had enough of this issue decided to dig deeper. <br /><br />So here's what I did: I took the same video clip and played it on my Pocket PC and on my desktop PC. The desktop PC was set at both 16-bit and 32-bit colour, while the Pocket PC was in the only mode it has: 16-bit. The sample is below, and depending on how sensitive you are to these things, you'll either notice the problem right away or wonder what I'm talking about... :lol:<!><br /><br /><img src="http://www.pocketpcthoughts.com/images/web/2003/wmp-quality-small.jpg" /> <br /><br /><span><b>So What Are We Looking at Anyway?</b></span><br />The video sample in question is 320 x 240, 24-bit colour, and at a 250 kbps data rate. I took the screenshots for the desktop computer with the video playing in Windows Media Player 10 Technical beta. For the Pocket PC, I was playing the video on the Dell Axim X30 and I took a screen capture using <a href="http://www.soti.net/default.asp?Cmd=Products&SubCmd=PCPro">SOTI Pocket Controller</a>. I was initially concerned that Pocket Controller was changing the video image, but I compared the screen shot with the video on the Pocket PC screen and they look identical.<br /><br />So what do we see in these images? The 32-bit desktop image looks perfect, because the video source is in 24-bit colour and there's enough colours to display it properly. When the desktop PC is in 16-bit colour mode, you can see some visual distortions, commonly called "banding". Gradiated colour is notoriously difficult to reproduce accurately if you don't have enough colours to work with. The Pocket PC is in 16-bit colour, so it should look the same as the desktop PC sample in 16-bit colour, right? Unfortunately that's not the case.<br /><br />The Pocket PC sample looks significantly worse than the 16-bit desktop sample. The banding is much worse - it's almost as if it's not really 16-bit colour! The differences are even more apparent <a href="http://www.pocketpcthoughts.com/images/web/2003/wmp-quality-big.jpg">on the bigger version</a> of the sample I created. I'm still in the process of searching for the right power charger for my 12-bit colour XDA in order to do some testing, because I'm beginning to think that Windows Media Player is displaying the video in 12-bit colour. That's only 4096 colours as opposed to the 65,000 colours that 16-bit colour has to offer.

[Robb Bates]

I'm kind of the opposite, I try to get the file size as small as possible. I make every effort to make sure the video is still watchable.

I see the distortion you're talking about, but it doesn't really bother me in the slightest. When I can fit four or five full length movies on my 256MB SD card, that's an accomplishment.

Maybe the difference is in how it gets rendered. Maybe the PC dithers with the 16 bit and the PPC doesn't.

Robb Bates

[R K]

Hey Jason,
Have you tried counting the colors in the images to test your theory?
I tried doing it myself by croping the "big" sample you posted, but due to the JPEG compression, I was getting highest color counts for the worst images.

[Jason Dunn]

Have you tried counting the colors in the images to test your theory?

How would I do that? I don't think my photo software has a "colour counter".

I tried doing it myself by croping the "big" sample you posted, but due to the JPEG compression, I was getting highest color counts for the worst images.

The big image is actually a PNG file so there's no lossy compression, but it's a 24-bit PNG, so that might muddy the issue somewhat.

[Fishie]

Simple, dont use WMP, recode the vids for Betaplayer

[x999x]

I'm not certain what you're expecting in terms of quality given the portable medium you're trying it on. Limitations and Portability go hand in hand, so given what we have to work with, I think that a level of adequate quality can be achieved, even for the most stringent purveyors of quality.

Since you think higher bitrates are sexy, have a go with BetaPlayer (http://beta.topcat.hu/), it handles high bitrate avi's with relative ease. I would recommend encoding in Xvid with B-Frames on, the level of quality you can retain is very nice. Additionally, you should find a link on the same page for encoding software, PocketDivxEncoder, which outputs avi's formatted specifically for the PPC.

I would be interested to see what your results are using a media player other than WMP.

[Ekkie Tepsupornchai]

Just judging from that image, there is no doubt that less colors are being rendered on the PPC. At first it looks like the two systems just may be dithering the image in different ways, but looking closer at the larger images suggest something else.

If you look at the 16-bit PC image (the large image), you can see 2 types of banding: a moire type of banding radiating from the sun and a "sun-ray" type of banding (only noticeable on the large image). Well, the "sun-ray" banding is less noticeable on the PC because there are far more bands... meaning a larger pallette of colors are getting used. Looking at the PPC version, the "sun-ray" bands are larger and more blocky... meaning less colors. There is also no moire pattern on the PPC image except for the area right above the sun where a few large "moire bands" exist.

Even if you look at the strand, the shadows are much more gradual on the PC version.

There's no doubt in my mind that the PPC image is using less colors... I wouldn't be surprised if that truly is 12-bit color.

[Jason Dunn]

Simple, dont use WMP, recode the vids for Betaplayer

If you're suggesting that the colour banding is because of the video format (WMV), that doesn't make any sense - the video file is of pristine quality and looks great on the desktop. If the limitation is the 16-bit colour on the Pocket PC, all video players will have the same problem. If, however, the problem is with WMP, then another player might do the trick. I'll check it out!

[R K]

How would I do that? I don't think my photo software has a "colour counter".

Sorry. I assumed that almost any photo editing software would come with a color counter, but after I took a look at some of mine, I found that to be a false assumption.
If you don't mind downloading some software, a freeware image viewer called <a href=http://www.irfanview.com/>IrfanView</a> can count colors in images. It's pretty safe to use, as it gives you clear control over file associations from the setup program.

[Jason Dunn]

I'm not certain what you're expecting in terms of quality given the portable medium you're trying it on. Limitations and Portability go hand in hand...

Sure, I'm very much aware of that, but I don't think I'm asking for all that much: I just want great quality video. :-)

Since you think higher bitrates are sexy, have a go with BetaPlayer (http://beta.topcat.hu/), it handles high bitrate avi's with relative ease.

This has nothing to do with bit rates - the X30 can play WMV files at 1000 kbps. This is about colour dithering, and perhaps a flaw in WMP.

[jayman]

I have to agree with Jason - I am a sucker for quality and have found that in general WMP is not up to the job - betaplayer is now on a new version and I can not recomend it highly enough - check out the free Matrix test videos and be prepared to be blown away. The benchmark util also rocks. I have found that it is best to fully exit all programs when using any media player and turn off the radio if your PPC is phone edition.

I also believe DVD pocket studio encodes directly into Xvid which can be read by this player.

[x999x]

I'm a big digital video enthusiast, so I dream in 8000 Kbps data streams.

x999x wrote:
Since you think higher bitrates are sexy, have a go with BetaPlayer, it handles high bitrate avi's with relative ease.

This has nothing to do with bit rates - the X30 can play WMV files at 1000 kbps. This is about colour dithering, and perhaps a flaw in WMP.

Your opening statements lead me to believe otherwise. In any case, please try what I've recommended, from one video buff to another.

[blazingwolf]

perhaps a flaw in WMP.

That says it right there Jason. Try BetaPlayer. I think you will see a difference.

[Jason Dunn]

Your opening statements lead me to believe otherwise. In any case, please try what I've recommended, from one video buff to another.

Sure, I'll give that a try, but my point was that the visual artifacts from low bit rates look completely different from colour dithering/banding, that's all. :-)

[Fishie]

Simple, dont use WMP, recode the vids for Betaplayer

If you're suggesting that the colour banding is because of the video format (WMV), that doesn't make any sense - the video file is of pristine quality and looks great on the desktop. If the limitation is the 16-bit colour on the Pocket PC, all video players will have the same problem. If, however, the problem is with WMP, then another player might do the trick. I'll check it out!The problem IS WMP which to my knoledge outputs only in 12 bit colour, even on CE based hardware that have more then 16bit colour.

[Sven Johannsen]

I'm not certain what you're expecting in terms of quality given the portable medium you're trying it on. Limitations and Portability go hand in hand...

Sure, I'm very much aware of that, but I don't think I'm asking for all that much: I just want great quality video. :-)

Then buy a Portable Media Center or portable DVD player. It's a fact of life that two things nailed together almost never do something as well as the individual parts did. Audio geeks don't buy all-in-one stereo systems for a reason. The more stuff you make the PPC do, the more compromises are going to be made on the individual components to keep them affordable and portable.

I'm not saying you aren't justified in wanting excellent video. But another is justified in wanting better audio, and another in wanting faster processing, and another in better connectivity and on and on. Technology advances will unlikely get the quality you want into the PPC, but that will be accompanied by quality enhancements in full sized/dedicated platforms that will still make you dissappointed in the smaller rendition.

The secret to happiness is not having what you want, but wanting what you have ;)

[Ekkie Tepsupornchai]

I'm not certain what you're expecting in terms of quality given the portable medium you're trying it on. Limitations and Portability go hand in hand...
Sure, I'm very much aware of that, but I don't think I'm asking for all that much: I just want great quality video. :-)
Then buy a Portable Media Center or portable DVD player. It's a fact of life that two things nailed together almost never do something as well as the individual parts did. Audio geeks don't buy all-in-one stereo systems for a reason. The more stuff you make the PPC do, the more compromises are going to be made on the individual components to keep them affordable and portable.
While I understand your viewpoint, I don't think it's that unreasonable to expect better from WMP. Considering that the PPC platform has been dominantly 16-bit (with exception for the legacy iPaqs) for quite some time, is it really that farfetched to expect WMP to output in 16-bits? Technically speaking, it shouldn't be a hardware modification that is needed to make this work (afterall, Jason's not complaining about a lack of 32-bit support or 8000Kb/sec streaming capability).

[scargill]

This is about colour dithering, and perhaps a flaw in WMP.

hmmm...although I can see why you would want better quality video and possibly expect it, why would this necisarrily be a flaw.
Dithering a 24bit video down to 16bit takes up alot of processing power and while your PC might beable to handle it, that doesn't say your PPC can (or PPC WMV supports it) my answer would be to re-encode the video in 16bit with dithering enabled in the endcoding.

[Ekkie Tepsupornchai]

This is about colour dithering, and perhaps a flaw in WMP.

hmmm...although I can see why you would want better quality video and possibly expect it, why would this necisarrily be a flaw.
Dithering a 24bit video down to 16bit takes up alot of processing power and while your PC might beable to handle it, that doesn't say your PPC can (or PPC WMV supports it) my answer would be to re-encode the video in 16bit with dithering enabled in the endcoding.
Your answer seems to suggest that you know WMV does indeed support 16-bit playback (just not the ability to dither down to 16-bit). Do you know this to be true or is that just a suggestion?

[jeffmd]

Being a video/audio nut, I can wholy see the flaws the pocket pc has. how ever out of my entire list of "wants and needs" for pocket pc video playback, 24 bit color isnt high on it. The reason is the screen size and resolution hardly makes the color loss noticable. Also as some have pointed out.. you should get the latest betaplayer if you havnt. banding can be reduced significantly with a good dither routien and betaplayers barly uses up any additional cpu power.

[klinux]

When I can fit four or five full length movies on my 256MB SD card, that's an accomplishment.

Four to five?! Wow, I ripped a 210 MB size DivX file of Finding Nemo @320 x 1xx (cannot recall the exact ratio) and it is only acceptable. Hard for me to imagine watching anything with lower bitrate than that.

[Sven Johannsen]

Considering that the PPC platform has been dominantly 16-bit (with exception for the legacy iPaqs) for quite some time, is it really that farfetched to expect WMP to output in 16-bits?

Doesn't it? Maybe you guys can tell 12 bit from 16 bit color at a glance. I probably could if it was the exact same screen on the same device, side by side. At least I could probably see the difference. None of those shots looked bad to me. Maybe you had to be there.

[Ekkie Tepsupornchai]

Considering that the PPC platform has been dominantly 16-bit (with exception for the legacy iPaqs) for quite some time, is it really that farfetched to expect WMP to output in 16-bits?
Doesn't it? Maybe you guys can tell 12 bit from 16 bit color at a glance. I probably could if it was the exact same screen on the same device, side by side. At least I could probably see the difference. None of those shots looked bad to me. Maybe you had to be there.
All I have to go off of is the screenshots because I actually don't use WMP for video (I use BetaPlayer). As for whether the shots look good or bad is rather subjective to each person. I can certainly see a noticeable difference beween the two 16-bit shots (especially when looking at the enlarged versions) and looking at the shots, I probably would have made the same guess that Jason did (that WMP is playing back in 12-bits).

It is possible that (as another poster suggested), that PPCs don't possess the horsepower to properly dither from 24 to 16-bit. I also just had a flashback from 7-8 years ago of the original nVidia Riva 128 cards that came out for PC. They were blazing fast gaming cards, but known for horrible 16-bit dithering. Perhaps the issue is not the # of bits, but the dithering quality. If either is the case, then this might just be a case of us having to wait for better graphics processors.

But if the difference between the shots is indeed indicative of WMP playback being 12-bit instead of 16-bit, then I don't understand why it would be unreasonable to expect 16-bit playback.

[Jonathon Watkins]

Maybe you guys can tell 12 bit from 16 bit color at a glance. I probably could if it was the exact same screen on the same device, side by side. At least I could probably see the difference. None of those shots looked bad to me. Maybe you had to be there.

I can see it straight away but then again I do a lot of digital photography so I am used to looking for flaws in picures in order to optimise them.

It's what you are used to I guess.

[Glisson]

I'm with Klinux. How could even 2 full length movies on a 256 MB card be viewable? I did a Matrix rip and even increased the quality a bit and although viewable it still had some serious pixelation during the "action" scenes. I do agree that there has to be some "give and take" when compressing video down however and find all of the samples Jason showed us acceptable. I also think if it says 16 bit it should look the same on all platforms. Either it's capeable of doing it or it's not and don't say it's somthing it's not.

Everyone thouroughly confused?!

Glisson

[Exempli Gratia]

I have a X3, and have been upset about the same kind of dithering shortfall. Oddly, I don't think I saw this on my old Tosh. e310 (WMP8 I think). Could it be a WMP9 thing? A Dell thing (don't see how). Have you had a chance to try this on the XDA you were mentioning (or other PPC)?

[Ekkie Tepsupornchai]

I'm with Klinux. How could even 2 full length movies on a 256 MB card be viewable?
Video is like music... everyone has their levels of what they deem acceptable. I know some people refuse to listen to music encoded any lower than 160kbps while others can't tell the difference between 64kbps and 160kbps.

The other thing to consider with video is resolution and framerate. You can scale back the bitrate quite a bit by sacrificing either or both. I know many find 12fps quite acceptable and some others view their video in portrait mode.

For me personally, I don't like to sacrifice any of those items (my movies tend to range between 240-300MB), which is why I had to buy myself a 4GB MicroDrive! :twisted:

I did a Matrix rip and even increased the quality a bit and although viewable it still had some serious pixelation during the "action" scenes.
Are you ripping to WMV or to AVI (DivX)? If you use the latter, then I'd recommend ripping to variable bit rate video (multiple-passes). That will take care of pixelation during action sequences.

I do agree that there has to be some "give and take" when compressing video down however and find all of the samples Jason showed us acceptable.
I don't think any of us are really debating whether the shots Jason showed were of acceptable quality. The debate is in regards to the difference in quality seen when playing back the same video on the PC vs the PPC.

[picard]

i don't think WMP uses 12bit RGB. there is no sense in it, the color space conversion from YUV to RGB isn't faster with 12bit. i checked some screen captures on my WM2003 device and RGB values are consisted from 32 levels in each channel. And probably this is the reason for the difference with desktop: WMP uses only 15bit (green is 5 bit too). And I can confirm that WMP doesn't use dithering, which could eliminate those bandings.

BetaPlayer supports dithering. you can even turn it on/off to check the difference. There is one other option called 'Optimal Update' which will be renamed in next version to 'Slow Video Memory' because it only helps with slow video memory devices (like h2210), and in some cases decreases the quality. so on a X30 try disabling it.

ps: so i will raise a little the priority to support WMV in BetaPlayer :) there are many WMV users out there who don't want to use MPEG4...

[Ekkie Tepsupornchai]

ps: so i will raise a little the priority to support WMV in BetaPlayer :) there are many WMV users out there who do want to use MPEG4...

8O 8O 8O

YOU ARE THE MAN PICARD!!!

[Jonathon Watkins]

Very good Picard. Could you post us a link for BetaPlayer for future reference? I'm always open to new options etc. :D

[picard]

BetaPlayer: http://beta.topcat.hu

[torok]

When I can fit four or five full length movies on my 256MB SD card, that's an accomplishment.

Four to five?! Wow, I ripped a 210 MB size DivX file of Finding Nemo @320 x 1xx (cannot recall the exact ratio) and it is only acceptable. Hard for me to imagine watching anything with lower bitrate than that.

Try using Windows Media Encoder instead of Divx. The whole world goes off about how good xVid and Divx are, but they both look like total crap at low bitrates compared to windows media. In tests I've done Windows Media at half the bitrate looks as good as xVid. Also, ALWAYS use a variable bitrate. The automatic software won't do it, you have to get your hands dirty.

http://pkulak.com/tutorial.php

[conflagrare]

When I can fit four or five full length movies on my 256MB SD card, that's an accomplishment.

Four to five?! Wow, I ripped a 210 MB size DivX file of Finding Nemo @320 x 1xx (cannot recall the exact ratio) and it is only acceptable. Hard for me to imagine watching anything with lower bitrate than that.

Try using Windows Media Encoder instead of Divx. The whole world goes off about how good xVid and Divx are, but they both look like total crap at low bitrates compared to windows media. In tests I've done Windows Media at half the bitrate looks as good as xVid. Also, ALWAYS use a variable bitrate. The automatic software won't do it, you have to get your hands dirty.

http://pkulak.com/tutorial.php

argh. I will NOT use Windows Media Encoder if anything then to stop them from dominating the codec world also. I would sooner re-encode all my videos into rmvb before I use Windows Encoder!

[jeffmd]

wmv is the better low bitrate codec.. and when I say low bitrates, I mean those suitable for streaming, or fitting 5 movies into 256 megs. WMV is just built better for not mistaking noise as new image data to be saved in P frames, and dynamic fps scaling so it can do things like cut off frame rates to preserve image clarity.

But the PPC player sucks.. and the WMV format is extreamly un-userfriendly when it comes down to the fact that a) your stuck using microsofts simplistic encoder to create them and b) editing movies in wmv is near impossible. usualy you need to recompress back into avi.

[jonathanchoo]

I agree that this might be a flaw in WMP. The quality are quite bad when compared to DivX at higher bitrates. My h4150 using BetaPlayer can handle 1300kbps, 25fps as does my T3 (MMPlayer) when set at 320x240 resolution video although at lower bitrates (400kbps) I noticed WMP have better quality when compared to 400kbps DivX.

I would not encode all my videos/audios in WMV and WMA format. I rather stick with DivX for my videos and OggVorbis for my audios so I can freely switch platform whenever I want to without wasting my CPU time to re-encode all my videos again.

[elehcdn]

I am using PocketTV to watch MPEG2 from a 1 GB CF card. For me, on my iPaq 2215 the image quality is pretty good. I do have a limitation of about an hour and 45 mins on the card, though.

[jeffmd]

#1 what are you playing mpeg2 with?

#2 you do know mpeg2 is a pretty sad compression? it gives hq video at gigantic bitrates (dvd) but you can accomplish the same results in 1/4 the space with divx. mpeg2 is alive and kicking because there is money behind it, but there is a reason you don't see "rips" stay in mpeg2 form. its just not good.

[dineshmj]

Hello Jason,

The PDA operating system (Pocket PC 2003 SE or WM 5.0) is capable to "request" its "display" device to render images in 24-bit, but since most of the displays are 16-bit capable only, they render the images from the OS in 16-bit, thus losing several colors in the process.

For example, when you have a photo taken in SONY digital still camera copied on to a PDA, the PDA software would be able to show the image in 16-bit only, thus giving an inferior rendering of the "available digital information".

The SOTI Pocket Controller does not "scan" the PDA screen. Rather, it gets the images directly from the PDA operating system through the ActiveSync application. Thus, it would be able to show the pictures in the best possible colours the source image material has.

In your test, if you viewed the sunset video on a Desktop PC and a PDA together, you can note that the video rendering so very much inferior to the desktop one.

Thanks,

Dinesh M Jayadevan



I'm a big digital video enthusiast (http://www.digitalmediathoughts.com), so I dream in 8000 Kbps data streams. 8) I'm a big stickler for quality, and I'm always pushing the limits on the quality of video playback on mobile devices. So the issue of video quality on the Pocket PC has been bugging me for a long time. I've ignored it/put off testing it for several years, but when I was testing the video playback on the X30 (it's awesome for video!) I had enough of this issue decided to dig deeper.

So here's what I did: I took the same video clip and played it on my Pocket PC and on my desktop PC. The desktop PC was set at both 16-bit and 32-bit colour, while the Pocket PC was in the only mode it has: 16-bit. The sample is below, and depending on how sensitive you are to these things, you'll either notice the problem right away or wonder what I'm talking about... :lol:<!>

http://www.pocketpcthoughts.com/images/web/2003/wmp-quality-small.jpg

So What Are We Looking at Anyway?
The video sample in question is 320 x 240, 24-bit colour, and at a 250 kbps data rate. I took the screenshots for the desktop computer with the video playing in Windows Media Player 10 Technical beta. For the Pocket PC, I was playing the video on the Dell Axim X30 and I took a screen capture using SOTI Pocket Controller (http://www.soti.net/default.asp?Cmd=Products&SubCmd=PCPro). I was initially concerned that Pocket Controller was changing the video image, but I compared the screen shot with the video on the Pocket PC screen and they look identical.

So what do we see in these images? The 32-bit desktop image looks perfect, because the video source is in 24-bit colour and there's enough colours to display it properly. When the desktop PC is in 16-bit colour mode, you can see some visual distortions, commonly called "banding". Gradiated colour is notoriously difficult to reproduce accurately if you don't have enough colours to work with. The Pocket PC is in 16-bit colour, so it should look the same as the desktop PC sample in 16-bit colour, right? Unfortunately that's not the case.

The Pocket PC sample looks significantly worse than the 16-bit desktop sample. The banding is much worse - it's almost as if it's not really 16-bit colour! The differences are even more apparent on the bigger version (http://www.pocketpcthoughts.com/images/web/2003/wmp-quality-big.jpg) of the sample I created. I'm still in the process of searching for the right power charger for my 12-bit colour XDA in order to do some testing, because I'm beginning to think that Windows Media Player is displaying the video in 12-bit colour. That's only 4096 colours as opposed to the 65,000 colours that 16-bit colour has to offer.