Tag Archive for 'video'

iMovie '09 HD FAQ

Published on April 13, 2009 in how-to.

After posting my iMovie ‘09 HD guide, I got a lot of questions, which I replied to in the comments. Here is a summary of all the points I covered:

  1. My camera shoots in 720p, or 1080p. Do I need to jump through hoops to use it with iMovie?
    No. Just import as “Full” size and use iMovie’s own export functions. If you want greater than 720p output, use the “Export using QuickTime” option and choose “1920 x 1080 HD”, H.264, 16200K (ish), and AAC 128K audio.
  2. Can I deinterlace the source video and then re-import it in order to use iMovie’s image stabilisation?
    Yes, you can. However, if you’re happy with 720p output, then this is no longer necessary thanks to iMovie’s new 720p export mode.
  3. Can I use the “Export” function of JES to skip encoding with QuickTime afterwards?
    Yes, you can. Bear in mind that if you want to encode to two different sizes then you will end up deinterlacing it twice and this will take longer.
  4. Can I encode to 50(PAL)/60(NTSC) frames a second output?
    Yes, select “Both Fields” in JES. Be aware that such video isn’t compatible with YouTube, Vimeo etc, and that 1080p50/60 video doesn’t play properly on many computers, as the bitrate is too high. 720p50/60 is fine.
  5. What camera should I buy?
    I prefer Sony cameras, but brand is a matter of taste. Make sure it shoots in AVCHD format. If you want 50/60fps output you’ll want a 1080i camera. If you want to avoid the entire interlacing issue and are happy with 25/30fps output (the normal rate), try a 720p or even 1080p camera.

    If you live in the UK and buy your camera from Amazon using this link, then Amazon will give me a few pounds. Thank you very much.

8 Comments Tags: , , , .

Creating higher-quality HD video with iMovie '09

Published on March 2, 2009 in how-to.

This used to be a tutorial on how to export 720p video from iMovie ‘09 for sites like YouTube or Vimeo. Apple have now added a 720p export option to iMovie ‘09 version 8.0.1, so if this is all you want, you can stop here. Run Software Update for the latest version of iMovie.

But if you have an HD camera that shoots in 1080i, and you want higher quality video output, follow this guide.

Please note that I don’t have the time to answer every comment I get on this post, and I’ve had a lot. Please scan through the other comments to see if someone else has asked your question, and re-read my guide carefully. Thanks.

Since this guide was written, Apple have released Snow Leopard and QuickTime X. This guide still applies, but you will have to use QuickTime 7 (which isn’t installed by default), instead of QuickTime X. QuickTime X is still too limited to be useful.

Also see the FAQ.

Note: This guide is for users of iMovie ‘09 and 1080i video cameras. If you have an older version of iMovie (including iMovie ‘08), this guide won’t work for you. If you have an HD camera that doesn’t shoot in 1080i (such as one of the “Flip” cameras, or most digital still cameras that also shoot HD video), this guide won’t work for you.

By default, Apple’s iMovie ‘09 software will only export video at up to 720p, and at 25fps. (This tutorial will use PAL framerates, but if you live in America or another NTSC country, it will still work for you. Just read 30 instead of 25, and 60 instead of 50.) 1080i video cameras, however, shoot 50 frames a second. It is possible to exploit this interlaced format and end up with 1080p video, optionally at the full 50 frames a second. (Note that you need a very fast Mac to play 1080p50 video. You should probably choose either 1080p25 or 720p50. Alternatively, the Sony Playstation 3 makes an excellent 1080p50 video player.)

Here’s how you can get the most out of your 1080i video camera.

Continue reading ‘Creating higher-quality HD video with iMovie '09′

161 Comments Tags: , , .

DIY Slingbox

Published on May 3, 2007 in how-to.

Yesterday from a dusty shelf I discovered my Sony DV camera. And after playing with it for a while I discovered (or possibly re-discovered, as I might have just forgotten) that it has analogue video inputs that it will digitise and then spit out of the DV port.

So this gave me an idea – this is essentially what the Slingbox does, except the Slingbox outputs a network stream rather than DV video. But I have a Mac Mini sitting underneath my TV downstairs, and that has a DV port on it…

So, after a lot of bodging and hacking and plugging of cables… I have this:

Patricia Hewitt in a window! Or, more accurately, the output of my Sky box being converted to DV, fed into my Mac Mini, transcoded, and then multicasted (yeah baby) across my house LAN.

And here’s how I did it.

My camera came with a video cable ostensibly for spitting out video to your TV – but it works backwards too, so I connect it to the back of my Sky box.

(Dusty, yuck.)

The other end connects to my camera, and another cable feeds DV out from my camera and into the back of my Mac Mini.

On the Mac Mini I download and install QuickTime Broadcaster, which is free. Setting it up, I start with the “LAN” presets for both Video and Audio, then hit “Show details” and do a few modifications. The Audio settings work unchanged except for choosing “DV Audio – first two channels” for the Source. Video settings look like this:

Things I changed are:

Size: 512×288.
288 is half the vertical lines of PAL. If I wanted full resolution I would have chosen 576 lines but the CPU in my Mac Mini isn’t capable of encoding that at 25fps. Halving the vertical resolution also has a handy side-effect of deinterlacing the video. 512 pixels wide results in a 16:9 display, for non-widescreen programs I would choose 384, but 99% of all UK TV is widescreen, so I’ll never need to change this. NTSC users might choose 427×240 or 320×240.

Quality: High
Frames per second: 25 (30 if my source was NTSC.)
Key frame every: 50 (60 if my source was NTSC.)
Limit data rate: Off (No point on a LAN.)

Network settings:

Things I changed are:

Transmission: Multicast

Then just hit “Generate IP Address” and you’re done.

Save the settings as an SDP file and then hit “Broadcast”. From another Mac (or PC), load up the SDP file and voila! DIY Slingbox.

Advantages over a Slingbox:
* No extra hardware to buy. (If you already own a DV camera and Mac server of course. You could also use a dedicated DV bridge if you have one.)
* More than one person can watch.
* Better video and audio quality.

Disadvantages over a Slingbox:
* No remote control functionality. (Which I’m doing by using an TV Link and existing RF cabling. Not ideal.)
* Harder to setup.
* Doesn’t work over the internet. (Though it could do, if have access to QuickTime Streaming Server.)

6 Comments Tags: , .