apple ipod video converter software for ipod classic

apple ipod video converter software for ipod classic

Even today, however, the video formats supported by the iPod, Apple TV, and iPhone are relatively limited compared to the number of formats available on the market. This means that just about any content that you want to view on these devices is going to require some type of conversion process. The advent of these new devices has complicated the landscape even further, since more options are now available for both the viewing and encoding of videos, but with these changes come more considerations about how to encode video for the best possible viewing experience.

In later articles, we’ll look at some of the specific tools and options available for converting video to an iPod, iPhone or Apple TV ready format, and some of the pros and cons of each. Before going into that, however, it’s important to start with a discussion of the video formats that are actually supported by each device so that those looking to convert their own video content can make informed decisions about the options available and the best resolution and format to use before starting the lengthy encoding process.

Apple’s Choice of Video Formats

In the fall of 2005, Apple took their first steps into the portable video market with the fifth-generation iPod with video capabilities. This original “video iPod” sported a 320x240 screen and supported playback of videos encoded only at that maximum resolution using very specific formats. At the same time, the iTunes Store began offering video content in these formats suitable for playing on the iPod.

The limited content available on the iTunes Store, and the limited availability of it outside of the U.S. meant that many iPod owners immediately turned to converting their own videos into a format suitable for viewing on their iPod, and a plethora of utilities became available to automate this process.

The following year came an upgrade to the fifth-generation iPod providing higher-resolution video playback. This was soon followed by the Apple TV to provide playback of video content on your home entertainment system, and then the iPhone, providing a more natural widescreen portable video experience.

The iPod, Apple TV and iPhone will play back videos encoded using either the MPEG-4 or H.264 codecs. These are open-standard video formats, and not in any way proprietary to Apple, but at the same time do not represent a broad portion of the video content that is currently available outside of the iTunes Store. Further, this does not represent the video standard that is used by most video recording devices, TV recording devices, or commercial DVDs. The result is that finding video content from anywhere other than the iTunes Store that is already encoded in an Apple-ready format is going to be difficult, and much of this content will therefore need to be converted.

For example, most commercial video cameras use either uncompressed Digital Video (or “DV”) or MPEG-2. Commercial DVDs also use MPEG-2 as their format. Videos downloaded from the Internet can be in any number of formats, including DivX, Windows Media Video (WMV) or QuickTime, among others.

Apple’s likely reason for these particular choices of codec is that they are an open, established standard, and they both provide a very high level of video and audio quality for a given file size. MPEG-4 has historically been very good in this regard to begin with, and the H.264 codec has only improved on the quality and file size efficiency.

As one would expect, when developing a portable video playback device, the quality-to-size ratio is very important both in terms of maximizing the amount of content that can fit on the more limited storage of a portable device, as well as maximizing the battery life of the device, as larger content can require additional processing power, thus shortening battery life. The H.264 codec appears to have been a natural fit to address both requirements, as well as providing a stable, open standard for Apple to use for their preferred video format.

Content on the iTunes Store uses the H.264 codec exclusively. Content you encode yourself can be encoded into either H.264 or MPEG-4, although H.264 will generally provide better quality for a given file-size, it also takes longer to encode.


Resolution and Bit-rate

Two other important considerations with video playback and the quality of the resulting file are the resolution and the bit-rate. The resolution simply refers to the dimension of the screen image, in terms of the number of pixels wide by the number of pixels high (ie, “640x480”) while the bit-rate refers to the amount of data that is actually encoded to make up a single second of video playback, normally expressed in either kilobits per second or megabits per second. This is the same concept as bit-rates for audio formats such as AAC and MP3.

Naturally, the higher that both of these numbers are, the better the quality of the resulting image will be. These factors both work together, however, since the resolution simply specifies the number of pixels available in a specific frame, and the bit-rate specifies how much actual information is being used to generate those pixels.

Without getting into too much technical detail, modern lossy video compression formats actually work not by encoding every single pixel of every single frame of a video, but rather simply encoding the information that changes between frames. “Reference frames” are taken at certain points, and the remaining frames are built based on what changes between each frame.

To conceptualize this, imagine watching a pro golfer make a putt:  Most of the scenery, the trees, the sky, and the golf course itself remains relatively unchanged throughout the putt, with only some motion from the golfer and of course the little white ball rolling across the green. Encoding every single frame of this would take up a lot of storage space (the equivalent of several hundred high-resolution JPEG files), when in reality very little is changing between frames. As a result, only the information that is different in each frame actually needs to be stored, and this can later be applied to the original reference frame to build a smooth video playback motion.

The bottom line is that this makes for significantly more efficient file sizes and storage of video content, and in fact is the same technology that DVDs use with the MPEG-2 format. Without MPEG-2 compression, a 90-minute DVD movie would actually occupy well over 167 GB of space, rather than fitting comfortably onto a 4.7 GB DVD.

How it directly affects the concept of bit-rates, therefore, has not to do with how much data is actually being encoded for each frame, but how much data is available to record the differences in frames. A high-resolution video with a low bit-rate will produce a more blurry image as well as visible signs of “artifacting” (distortion, blocking effects and jagged edges) on high-motion action sequences.

So what resolution and bit-rate should you use to encode your video content?  Logic would suggest that one should always use the highest settings possible, but much of this has to do with what your source content is, and the limitations of the equipment you’ll be using to watch it.

For example, if you only ever intend to watch video content on the iPod’s 320x240 screen, it would obviously be a waste of disk space and encoding time to convert these videos to any resolution higher than this.

Further, if your original source video is already at a smaller resolution, there is absolutely no point in encoding it in any higher resolution or bit-rate, as you’re not going to magically gain any resolution that wasn’t there in the first place. In our experience, consumer-grade conversion tools that promise “upconversion” of video formats are generally not worth the effort.

Likewise, even though the Apple TV supports a high-definition quality of video output (1280 x 720), if you are converting standard-definition DVDs, there is no sense in encoding them in anything beyond their original resolution.

So what are the different resolutions and formats supported by Apple’s video playback devices?  The table below provides an outline of the maximum resolutions supported, as well as the output quality of the device itself: