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Apple iMovie 8.0.5 update debuts new iFrame video format

Prince McLean, AppleInsider

Apple has created a new video format called iFrame for use by camcorders, allowing optimized import into iMovie for editing.

Apple iMovie 8.0.5 update debuts new iFrame video format
A support article describing the new format, which was just added to iMovie 09 in the 8.0.5 update, says the new iFrame Video format “is designed by Apple to speed up importing and editing by keeping the content in its native recorded format while editing. Based on industry standard technologies such as H.264 and AAC audio, iFrame produces small file sizes and simplifies the process of working with Video recorded with your camera.”

Support for the new format was announced by Sanyo, which has added iFrame recording to two of its new camcorders introduced today, the HD2000A and FH1A.

The new iFrame format captures standard H.264 video at 960×540, a quarter the resolution of full 1080 HD. The new cameras from Sanyo default to record in the iFrame format, but can also be set to record in full 1080 HD.

Finding a format

Digital camcorders began recording in MJPEG (Motion JPEG, a series of still photo captures) before moving to the better compression of the popular DV format. While DV recording allowed for high quality capture, it wasn’t optimally designed for direct editing in QuickTime; it uses non-square pixels and is oriented toward TV resolutions and aspect ratios.

JVC improved upon the consumer DV format with its HDV format (also supported by Canon Sony and Sharp) using MPEG-2 video similar to a DVD, although HDV uses a transport stream rather than a program stream (like DVD), as it is optimized for delivery rather than storage. The recording format is also optimized for playback rather than editing. Importing HDV into iMovie using an intermediate codec makes editing more efficient, but also requires more disk space.

A variety of other competing digital formats have appeared on the high end, including Panasonic’s DVCPRO HD (based on DV encoding) to Sony’s DVCAM (also based on DV) and XDCAM EX (using MPEG-2).

Panasonic and Sony paired up to create the AVCHD format, which is based on modern MPEG-4 H.264 video. However, AVCHD still multiplexes its audio and video into an MPEG transport stream rather than recording it as a standard MPEG-4 file. In order to edit the AVCHD video captured by camcorders, iMovie still has to import and transcode it into the Apple Intermediate Codec, which requires time and consumes lots of disk space. Final Cut Pro similarly imports AVCHD video into AppleProRes.

By floating the new iFrame format using the same standard MPEG-4 H.264 video, Apple hopes to simplify the import process for consumers, making it easier and faster to ingest camcorder video for editing.

The name of the new format appears to reference both Apple’s consumer product line and MPEG’s <a href=“http://www.roughlydrafted.com/RD/RDM.Tech.Q1.07/6FFE4614-E1AB-45C7-8611-19D06ECCAD9F.html”>I-frames</a>, or intraframes, which act as keyframes in the video recording. Between full I-frames, MPEG compression uses P-Frames or predictive frames, which only present what has changed since the last I-frame, as well as B-frames, or bidirectional predictive frames. These present part of a picture like a P-frame, but reference changes relative to a future frame. In other words, B-frames come in advance of an I or P-frame that fills in the missing details.

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  • pixelkisser

    Erm, there’s lots of stuff in this article which is not quite right. The whole issue is compounded by Apple calling a codec by a name (iframe) which already has a particular meaning in the world of video codecs.

    DV as a codec is actually much easier to edit than HDV as it’s itself “iframe” codec – ie. it keeps every frame separate and doesn’t compress across frames. HDV does, and thus requires a lot more computing power to play it back and edit in real time. HDV is not like a DVD stream, it’s just MPEG2 compression, and when pulled in over firewire becomes a regular QT movie. Okay, so DVD is MPEG2 as well but it’s a wrapped up vobbified MPEG2 at a substantially lower bitrate and there’s really no sense in comparing them.

    All current macs and laptops shouldn’t have a problem working with HDV quicktimes – the problem arises when you want to overlay processor heavy effects and transitions : that’s when slower macs will start grinding down.

    It sounds as though Apple’s “iFrame” codec might be a variant or version of the newly announced low end ProRes422 codecs. These are all “iframe” codecs and thus require less processing power.

    If iFrame really is only 540 I find it bizarre that Sanyo would advertise HD cameras which then feed in pictures at a resolution LOWER then even SD (PAL SD is 576 lines).

    Non square pixels are a pain I agree but if you do anything in HD that’s not full raster (ie. 1920*1080) or anything that ends being seen on a TV / DVD you’re going to have to deal with rectangular pixels at some point.

  • enzos

    Seth Weintraub at Computerworld conjectures:
    >Apple’s posted a quick KB article on the format. From the KB we know that the resolution is hard set at 960×540. That is exactly a quarter of 1080P HD size. It is also 20 pixels away from being four times the size of the iPhone screen. A nice round multiple for easy up and down sampling? http://blogs.computerworld.com/14908/what_is_iframe_and_why_did_apple_release_it_today

  • SteveS

    Who’s going to use their HD camcorder to record 1/4 HD quality video? That’s asinine. You always record at the highest quality and down sample to meet the target requirement. I have no issue of offering this as an option, but iFrame should accommodate full 1080p quality.

  • http://backaccessward.blogspot.com beetle

    Wow, lucky me! I am in the market for a new camcorder (but not an HD camcorder) and now I have the key feature to look for. Unfortuneatly, it will probably be a year or more before the low end models pick this up!