Apple makes things simpler by eliminating dozens of popular alternatives (AVI, WMV, DivX, Xvid, FLV, MKV etc) and only allowing two real digital video options: MPEG-4 at 640 x 480 pixels and H.264 at up to 720p on most iPads, and up to 1080p on the iPad mini and iPad Air. You don't have much choice if you want to use Apple iTunes and watch movies natively on an iPad or iPhone. It can be a problem if you are "upscaling" a DVD movie to 720p or 1080p. It's something to avoid if possible, and if not, to do only once.įortunately, this usually isn't a problem if you're reducing the movie's resolution – for example, converting a 1080p video to 720p to get a much smaller file size – or viewing it on a smaller screen. And, as you know, "transcoding" from one lossy format to another involves a loss in quality. MPEG-2 and MPEG-4 files are the equivalent of MP3 audio files in that respect. Now, video consumes a huge amount of space, so both DVDs and BDs use lossy compression to make the files smaller. HD TV sets will de-interlace videos automatically. Blu-ray also allows for the use of interlaced video and the 4:3 DVD formats for backwards compatibility. However, H.264/MPEG-4 Part 10 AVC – commonly known as H.264 – is the most widely used format.īlu-ray movies usually come in 16:9 widescreen resolutions of 1280 x 720 pixels, which is known as HD (High Definition) or 720p, or 1920 x 1080 pixels, which is Full HD or 1080p, where p stands for "progressive". Some early Blu-ray discs actually used MPEG-2, as that was the basis for digital production at the time. This led to the Blu-ray optical disc format, which mandates support for two new video standards: MPEG-4 AVC (Advanced Video Coding) and VC-1, the latter being based on Microsoft's WMV-9. This means we can now use much greater levels of compression to make files smaller, and yet still decode them fast enough to keep up the frame rate. The next generationĬomputers and processors have become cheaper and much more powerful since MPEG-2 was specified in the 1990s. As with MP3 audio files, there are just too many around. It is much more efficient (smaller files) and sounds better than MP2, which is antique – though, sadly, it's still used in Britain's antique DAB radios.įor future-proofing, MPEG-2 files are the next best thing to ISO images, and I don't foresee a time when PCs will be unable to play them. MP2 and AC-3 are the most common, and if you have to pick one of those, choose AC-3. DVDs can have audio tracks in PCM, DTS, MPEG-1 Audio Layer II (MP2), or Dolby Digital (AC-3) format. However, you will probably have lost any extras, including VMG (video manager) files, subtitles, hidden files, adverts and alternative audio formats. What you have done so far is to rip a couple of DVDs to MPEG-2 (.mpg), so you may have the full original video, but de-interlaced so it is now in the progressive display format used by computer monitors and HD TVs. You could also play the ISO disc image using a software DVD player, including VideoLan's VLC, or rip it using your choice of DVD ripping software. You could burn this copy to another DVD for backup purposes. If you want to preserve everything on a DVD, then the simplest option is to copy the whole disc as an ISO disc image. The 720 x 480 format came from America's NTSC television system and 720 x 576 from Europe's PAL. MPEG-2 was the obvious choice for DVDs as it was already being used for broadcast and cable television. The result is a resolution of 720 x 576 pixels at 25 frames per second, for 50Hz TV sets, or a resolution of 720 x 480 pixels at 29.97 frames per second, for 60Hz TV sets. The video is interlaced for display on ordinary TV sets. The video is held in VOB (Video Object) files. Most DVDs store movies in the standard MPEG-2 format (aka H.262) defined by the Motion Pictures Expert Group, though MPEG-1 is also supported.
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