Converting video for the Video iPod (Twelve Black Code Monkeys)

News and commentary on gadgets and technology: mobile phones, pda's, Tivo, Treo, digital cameras and photography and lots more gadget nirvana.

Converting video for the Video iPod

« H » Gadgets and Technology :: Levi Wallach :: email link

There are many programs currently available that will convert video of various kinds to a format compatible with the video iPod. While none of these are prohibitive in cost, I didn’t feel like spending lots of time downloading trial versions to figure out which one might work best, nor did I feel like spending on one that a few people like only to discover there’s another that actually does a better job. Since the video iPod is so new, many software companies that make converters are just now modifying their products to include conversion options for the iPod. Maybe in a month or two the dust will have settled a little more and we’ll start seeing some in-depth reviews comparing some of these applications to one another.

In the mean time, as far as I’m aware, the only free program that’s been available is one from the same people who brought you PSP Video 9 (a video converter for the PSP) and Videora. The name of the program is “Videora iPod Converter” and it has a wide (and sometimes overwhelming for a newbie) assortment of settings one can manipulate for your conversions. Aside from the obvious ones like resolution and bit rate, there are others like Qscale, and conversion mode that are not nearly as well known.

As with much freeware, there’s no real documentation available, nor is the program very straightforward to use. You need to create a profile for a given collection of settings, or use one of the programs presets. If you choose to use your own settings, you’re in no way guaranteed that they will work with the iPod. You may be able to get them into iTunes but they won’t transfer to the iPod if some setting is off.

Screenshot of Videora iPod Converter converting a file

Screenshot of Videora iPod Converter Profile Screen

The two settings that this happens for most often is bitrate and resolution. The iPod will only handle resolutions that add up to 230,400 pixels - whatever the width and height dimensions are, multiplied they can’t add up to more than this number or the file won’t transfer. Similarly, for H.264 files, iTunes will not transfer it if it has a higher bit rate than 768Kbps – although at least in this latter case there is a hack to get around this, thanks to a user on the Videor iPod Converter board named DaProphecy. Apparently the chip in the iPod that plays video has the ability to play higher quality video than Apple lets on in their specifications. iTunes prevents you from transferring in this higher bitrate despite it being playable, so you basically have to trick iTunes into transferring the file. This, of course, is ridiculous and should not require a hack to get around. Hopefully Apple will update iTunes and make this a non-issue.

Because of the massive numbers of settings, and no real clue as to which ones would work best in which cases, I determined to spend an inordinate amount of time transcoding a 55-second video clip into as many of these as made sense at the time. In all, I made 40 different conversions, although I’m sure I barely scratched the surface in terms of what I could have done. Still, I wanted to get a general sense of what each setting would do, how they would compare to each other in terms of the amount of time the conversion took, how big the file was, and what the quality of the video was both on the iPod and when exported out to a TV. I figured if I was going to convert my 200+ DVD library to video files for the iPod, that I should be fairly certain what settings to pick so that I don’t waste time converting to something which in the end wasn’t as efficient as another format in terms of time and storage space.

I set about creating an Excel spreadsheet, linked here, which contains all my data, as well as my impressions of quality. The first sheet shows various conversions to H.264, whereas the second sheet displays results for conversions to MPEG4. Both of these are compatible with the iPod.

To summarize my findings, much of it was predictable. Usually the higher the bit rate, the better the quality, although occasionally it was hard to tell the difference. When exported to TV, the higher the resolution, the sharper the image. However, there were some findings that I hadn’t expected. First of all, making a 2-pass conversion usually did not improve the video noticeably, but did double the time needed to convert. File sizes for 2-pass conversions were almost always about the same give or take, the only big exception being MPEG4 > QC-VBR mode, which decreased the file size by about 2/3, although unfortunately this smaller file size also equated with much poorer quality video.

While I probably will not use it extensively, the iPod’s ability to pipe the audio and video out to a TV is something that really interested me. While critics complain about the size of the iPod’s screen for video, you can’t complain about it if you pipe that video out a 27” (or greater) monitor. I own a 34” widescreen TV which I suppose is about the same as a 27” standard (4:3) TV and used that for testing these conversions (as well as viewing them on the iPod itself). One thing I found interesting was that some video artifacts were much more noticeable on the iPod than on the TV– for example some pixilation when clashing colors like red and green were adjacent to each other. Even some of the “blotchiness” of certain colors seemed less noticeable sometimes on that large screen. I was viewing it from about 5 feet away, which I think is equivalent to holding the iPod about 5 inches from my face! I expected all the defects to be much more obvious, but perhaps the interlacing of a TV screen somehow smoothes out some of these.

What I did find was that some of the higher resolution conversions I made, when played on my TV, were excellent in quality. Perhaps not quite DVD quality, but maybe equivalent to a VHS tape if not even cable or even satellite. Unfortunately, these same files, when played on the iPod, had artifacts that made them difficult to watch – similar to the “banding” that one might get and worn VHS tape. This was particularly evident whenever the camera panned at all. So my initial hope that I’d be able to convert one file and have it play in optimal quality on both the iPod as well as the TV was not to be. The lower resolution conversions are not terrible when viewed on the TV, but it’s pretty obvious that something’s off, at least from 5 feet away. The picture just isn’t very sharp, even with the best conversions. It’s a little like watching a 30-year-old TV.

As far as the conversions themselves go, they took a bit longer than I expected. Even the shortest one took about 15% more time than the clip itself, and the worst took 700% as long! Then again, you may have different results. I converted these on a 2.5-year-old laptop with a 2Ghz P4 processor and 1.25GB of RAM. Very possibly you have something newer and faster. File sizes varied greatly as well, from a small 3.4MB to a whopping 25.6MB for just this small clip. Luckily, the 2^nd Pass, which normally doubled the time to convert, was usually not a factor in terms of quality. And file sizes didn’t always equate with quality either.

This photo was taken from my TV. It was a lower bitrate setting and you can see blotchiness, pixelation, and other artifacts pretty clearly.

Here's another picture off of my TV, but this one at a much higher bitrate. While still not crystal clear, it definitely looks much better than the first image!

I have to divide my conclusion into to separate categories – best for iPod and best for iPod to TV. If one is mainly concerned with playing on the iPod itself, it seems the winner is probably H.264 > CBR at 768Kbps, 1 Pass. This has one of the smallest file sizes and fastest conversion times. It’s certainly possible that some may find some of the other modes to edge it out slightly, but most of those modes produce files that are at least double the size, maybe more, and take at least a little more time to convert. But if storage isn’t an issue (on the iPod itself, even at the higher 60GB level it still IS an issue), and your system is incredibly fast, or you have extra machines to do conversions for you, you may find it more worth it to try some of the other settings.

For iPod to TV, the winner seems to be MPEG4 > CBR at 544x408, 2500Kbps and one pass. This had one of the shortest conversion times and the smallest file size for a higher-resolution conversion, and rivaled or beat all of the other such conversions.

A final disclaimer: these quality settings are of course subjective. As they say, your mileage may vary. I’ve compared a pretty limited range of video information in a 55-second clip, and I’ve done this for each of the 40 files on both the iPod and the TV. That’s a lot of stuff to compare even for a relatively short clip. I’ve already spent a week or so transcoding and then reviewing all of these, but I can see where to really scrutinize this stuff in detail, one would need a larger clip with a lot more variations in color, motion, etc., and have the luxury of being able to review each clip about 20 times to note various things down. I’m not even an expert at any of this and so my impressions are from someone who is not a videophile per se, but just a gadget freak who also loves to watch DVD’s. So please take this all with a grain of salt. I did the best estimation I could within my limited timeframe, expertise, and tools, but I can’t claim this as being at all definitive. I look forward, in fact, to those who might be able to clarify, confirm, or dispute certain findings so that a more accurate picture for all can be obtained. In the mean time, I hope this serves as a decent primer for those who, like myself, found themselves lost in the sea of possible settings with no idea how they might translate into quality, time, and space in the real world.

posted Thursday, 1 December 2005
tags: mpeg videora transcode h264 video mpeg4 itunes ipod

Dinyar made this comment,

GREAT info.

Saves me all the effort in finding out Exactly what you have done.

Thanks for taking the time to share all this with us.

Dinyar

comment added :: 2nd December 2005, 01:33 GMT-05

connor made this comment,

thank you, i appreciate you spending the time to do that, this helps me a lot as i mainly use the ipod to output to my in-car tv and not for use on the ipod. thanks again.

comment added :: 2nd December 2005, 02:38 GMT-05

Cecilia made this comment,

Thanks, great info, since limited support at Videora! I've been transcoding most of mine as MP4s on the movie default, with a few minor changes, but this will give me an excuse to experiment some more.

comment added :: 2nd December 2005, 10:49 GMT-05

Radek made this comment,

Thank you,

for very nice comparison of video formats for iPod.

Radek

comment added :: 3rd December 2005, 01:23 GMT-05

balint made this comment,

thanks for working instead of me :)

comment added :: 7th December 2005, 15:15 GMT-05

tyler made this comment,

i cannot get 544x408 2500 to play or copy onto my video ipod. what do i need to do?

comment added :: 10th December 2005, 03:40 GMT-05

Levi Wallach made this comment,

Tyler, I would first of all turn on the enable console debug in Videora (under the console tab in Setup). That might give you a clue as to what the problem is.

But my guess is that you've run into one of Videora's bugs. The particular bug I'm thinking of is the one where you try to save a new profile but it saves the old info. So even though it says that those are your settings, they actually aren't. The debugging should actually show this.

The bug list that's on the Videora discussion board includes this and other bugs and workarounds. The bug I mentioned is the last one listed:

http://www.pspvideo9.com/forums/viewtopic.php?t=27 05&sid=618

comment added :: 10th December 2005, 08:22 GMT-05 :: https://twelveblackcodemonkeys.com

Matti made this comment,

Amazing work. Thank you. This is just what I needed.

comment added :: 13th December 2005, 14:57 GMT-05

Stephe made this comment,

Wow! now I have a practical application for this fucking video screen. Thanks a ton!

comment added :: 15th December 2005, 03:39 GMT-05

richard made this comment,

i cant transfer the converted ipod file to itunes.

comment added :: 16th December 2005, 12:54 GMT-05

jim made this comment,

Does anyone know of a decent setting for widescreen conversion (that will be outputted to a TV?) Thank you for all of your effort. I'm going to try the settings you recommend above for my 4x3 programs.

comment added :: 17th December 2005, 23:02 GMT-05

Levi Wallach made this comment,

Jim, widescreen should generally work the same way. So use the bitrate and mode that looks the best on the spreadsheet. However, you just need to change the resolution to fit whatever the content is. Not all widescreen movies are the same dimension. Some are 16:9, others are more. The DVD's should tell you, or search for the info on the net.

Now that I think about it, it's very possible that those wavy banding patterns I saw with MPEG4 conversions at higher resolutions may not be as much of an issue if you pump up the resolution on widescreen movies - since a lot of those seemed to be at the top of the image, and since widescreen movies have the black area at the top and bottom... Maybe it would work out well...

comment added :: 18th December 2005, 08:03 GMT-05

jim made this comment,

I guess what I need explained to me is WHAT ARE the 16x9 resolutions I can use. I don't quite understand the math behind it. Or maybe I just didn't get enough sleep...

comment added :: 18th December 2005, 09:51 GMT-05

Levi Wallach made this comment,

Aha! Yes, the math in all of this is a bit of a pain sometimes. I should have included a link to this freeware application called Ratio Calculater that helps you figure out the various resolutions that conform to the one you need. Here's a link:

http://www.1-4a.com/ratiocalculator/

Just specify the ratio and it will give you many different resolutions that conform to it. Just make sure the total pixel count (in this program it's "Area (h*w)" ) for MPEG4 is no more than 240,300. It needs to be even less for h.264, but I don't have those numbers in front of me. They are least 64,000, since I know it will display 320x240. Actually I think it is somewhere around 178,000, but not positive.

I'll probably update this blog entry just a bit in the coming days with this and some additional info as I make a few more tests.

comment added :: 18th December 2005, 10:54 GMT-05

Jim made this comment,

I'm trying the calculator and running a conversion now.

The only question I have is what set of numbers from the columns I should use. According to what you told me I should not go over 240,300 so I have to choose from 640x360 or 640x480? I'm going to try one, but it will take awhile to convert so if you come up with an answer before I'm finished I can abort and try again. (thank you again for all your help)

comment added :: 18th December 2005, 13:13 GMT-05

Levi Wallach made this comment,

Jim, if you multiply 640 by 360, you get 230,400, so that will work. 640 x 480 comes to 307,200, which is over. As I stated in my previous post, it's the "Area (h*w)" column. Vertical pixels times horizontal pixels equal total number of pixels. Just like length x width = area.

comment added :: 18th December 2005, 20:07 GMT-05