I recently acquired a Zune HD, which I am very much enjoying. I’ll write more about it after I’ve spent more time with the device, but I wanted to share a tip I’d learned about using it with Windows Media Center and recorded TV.
Recorded TV File Formats 101
Media Center in XP and Vista (pre-TV Pack 2008) records to a DVR-MS file format. In TV Pack 2008-enhanced Vista and in Windows 7 a new format called Windows TV (with the WTV file extension) is used for recording.
Why the change in format? The new Windows TV format supports dynamic format changes, such as video resolution, audio compression type, etc. If you think of watching a HD station on TV, some shows on a particular channel may be full HD (1080i) resolution, but other shows (or often the commercials within the HD show) may be of a lower resolution. The WTV format can encode these parts differently to optimize the recording, saving space and bandwidth.
It also enables cool features like multiple camera angles and language-specific audio tracks, the sorts of features you’d see on a well made DVD. There’s also enhanced metadata, better recording and recovery, and various other improvements. Most of this comes with version 2 of the Stream Buffer Engine in Windows 7.
That’s all techno-gweege though. The Zune software and devices have supported both formats for quite some time, unless they use Dolby Digital AC3 audio. That turns out to be a big gotcha, since that’s the audio format used for just about every digital video broadcast in the US and most other countries. This applies to both ATSC (over-the-air HD) and Clear QAM (from your cable connection).
Here in Portland where Comcast has already made the switch to 100% digital for their cable broadcasting, it means anything I record with Media Center can’t be transferred to the Zune. Herein lies the suckage.
Beating Your Recordings Into Shape
So the format isn’t supported, but we can transcode the files to a different format that is. Expression Encoder 3 can do this for us no problem, and even has profiles for targeting Zune and Zune HD devices out of the box. There is a free version available for download if you don’t have Encoder already.
Not so fast though… currently Expression Encoder 3 has a bug with AC3 audio in WTV files. On my desktop machine Encoder would crash outright when trying to import a WTV file; on my laptop it would report an error about not being able to find some audio codec identified only by GUID. In short, it no worky.
There are two options to work around this bug:
- Convert the WTV file to the older DVR-MS format. To do so in Windows 7 is easy; just right-click it in Explorer and select “Convert to .dvr-ms Format” in the context menu. It will create a copy of the original video in the older format.
- Install a third-party AC3 decoder. A free option with 32- and 64-bit support is available at http://ac3filter.net/.
(Hopefully they’ll have this bug fixed in an updated version of Encoder.)
Once you’ve done one of the two workarounds, you should be able to proceed with Encoder and transcode your video file for use on your Zune.
For output formats you have four choices: H.264 (MP4) or VC-1 (WMV) formats, and profiles for Zune HD or Zune HD (AV Dock Playback) for each respective format. The AV Dock Playback profiles encode 5.1 channel surround sound and a video resolution of 1280x720, which is going to eat up a lot more disk space than the standard Zune HD profile (stereo audio, 480x272). Since I can just watch my HD content via Media Center when I’m at home, I encode my files using the smaller Zune HD profile sized just right for its screen.
I’ve tried both workarounds and have had success with each. There does seem to be a minor issue when choosing H.264 (MP4) for the output format though; some metadata about the broadcast seems to be lost, resulting in the file not showing up in the TV section of your Zune video library. WMV handles this fine however. If you’re encoding your videos to be used on more devices than just the Zune, using MP4 may be more important than the categorization glitch.
I’m hoping to get a script or simple app going to automate this process, but this should get you going in the mean time.