Wednesday, June 18, 2008

Playing Video movies on your Ipod

By David B Smith

The main point at issue for anyone thinking about purchasing a video ipod is, 'what sort of videos can I watch on it?' The answer is that just about any video can be converted into an ipod-compatable format, but there are also a growing quantity of videos being released explicitly for the video ipod.

According to the Apple website, the new video iPod can screen video that comes in either H.264 or MPEG-4 formats. To be more accurate, the specifications are as follows:

* H.264 video: up to 768 Kbps, 320 x 240, 30 frames per sec, Baseline Profile up to Level 1.3 with AAC-LC up to 160 Kbps, 48 Khz, stereo audio in .m4v, .mp4, and .mov file formats.

* MPEG-4 video: up to 2.5 mbps, 480 x 480, 30 frames per sec, Simple Profile with AAC-LC up to 160 Kbps, 48 Khz, stereo audio in .m4v, .mp4, and .mov file formats.

For those unaccustomed to the specifications of digital video, this quite likely all sounds a bit confusing, but you need not be too anxious, as you only need to be aware of a handful of these numbers and specifications in order to get the most out of your new iPod.

We'll begin with H.264 video.

The highest video bitrate with the H.264 codec is 768 kilobits per second. The biggest picture size for your H.264 movie is 320 pixels wide by 240 pixels high, which is, by the way, the exact same dimension of your iPod's screen. Your iPod is capable of playing H.364 video at framerates up to 30 frames per second.

Most iPod applications do their encoding in accordance with this profile. As to the audio, it needs to be encoded as AAC audio up to 160 Kbps, 48 KHz, and can be in either stereo or mono. Note that the audio format is the same for both QuickTime movie and MPEG-4 formats.

The other video choice you have is the MPEG-4 video, which supports a much higher bitrate than H.264 video 2500 kilobits per second to be precise!

Using higher bitrates as expected also creates much larger files, which means that you end up with a smaller amount space for the storage of extra songs and movies. It comes down to a choice of trading off quality over quantity, though understandably how important this is depends entirely on the storage volume of your unit.

The greater picture size for the MPEG-4 video is 480 pixels wide by 480 pixels high screen in capable of displaying. Your iPod will minimise the picture uniformly so that everything fits on the screen. Again, the iPod can play videos up to 30 frames per second and your audio and file format options are the same as H.264 video.

So the chief question that remains is which format is Better H.264 or MPEG-4? In truth, it's a difficult question, as each format has its ups and downs.

Many would maintain that the H.264 format is better because it offers a high quality video at a file size that is much smaller compared to MPEG-4, and when it comes to picture quality both formats are indeed comparable, especially when encoded at the higher supported video settings. As for the speed of encoding however, most people agree that H.264 video takes longer than standard MPEG-4.

If we take a two-hour movie, for example, when you convert that to iPod using H.264 codec, the process can take considerably longer (especially with QuickTime haphazard Export function: 'Movie to iPod video').

To be brief, which ever format you decide on, you'll need to take into consideration a number of factors, including the number of movies and songs you are likely to want to store on your video ipod, the projected size of the individual files, the actual storage capacity of your video ipod, and your patience when it comes to the encoding process.

In truth though, deciding on an appropriate video format for your ipod is one of the more enjoyable choices that needs to be made in life, and shouldn't prove too much of a stress.

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