Tuesday, February 23, 2010

Windows 7 does USB audio correctly

I wasn't too impressed with USB audio in Windows XP and Vista. I had to manually switch between audio outputs, and I saw a few blue screens when unplugging USB audio device.

USB audio finally works right in Windows 7. When a USB audio device is plugged in, audio output switches to that device. When the device is unplugged, audio output switches back. I can even use my USB wireless headphones to listen to line in on the motherboard. Most importantly of all, USB audio doesn't crash Windows 7.

Tuesday, February 16, 2010

Concatenating DVD titles using Avidemux and Ifoedit

To join VOB files in a single set (such as VTS_01_1.VOB and VTS_01_2.VOB), you can simply concatenate them using a utility like cat. They are actually already concatenated on the DVD; they only appear separate in the filesystem because the standard limits file sizes to 1GB for compatibility purposes.

For joining multiple VOB sets, Avidemux seems like a pretty good choice. An entire VOB set can be opened by opening just the first file. (Avidemux asks if you want to index the file and append the other parts of the set.) Then, other VOB sets can be appended using the Append option in the File menu. Finally the basic video editing features in Avidemux can be used to remove duplicate or unwanted content.

The resulting video can be put onto a new DVD via Ifoedit. First, the audio and video need to be saved separately from Avidemux. Then, the DVD authoring functionality of Ifoedit can transform this into files go in a VIDEO_TS folder. Finally, the result can be burned using any DVD burning software which can burn video DVDs.

What doesn't work?

A lot of software in this area is annoying and/or broken.
  • DVD Shrink can easily put two titles on one DVD. However, it can't create menus or join them into one title. That makes navigation annoying.
  • If the VOBs are just concatenated, only the first title is playable.
  • VobEdit's "Join Clips" feature is useless here. When joining files, it gives each file its own VOB ID. When Ifoedit creates the IFO files, seeking only works within the first VOB ID.
  • Avidemux failed to index the VOB set that Ifoedit created. The VOB set is progressive, but the Avidemux index says it's interlaced. It's easy to change "Image : I" to "Image : P" in the index file; I just wonder whether there's something wrong with the VOB set.
  • MPEG Streamclip requires the MPEG-2 QuickTime component for preview.
  • VirtualDub and related programs can't save in MPEG-2 format.
  • Windows DVD would re-encode all the video even though it's already in the right format.

Tuesday, February 09, 2010

Deleting a file called "nul" in Windows 7

I tried to use "nul" instead of "/dev/null" in Cygwin. That created a file called "nul". When I tried to delete the file in Explorer, I got an interesting "Invalid MS-DOS function" error:

The file can be deleted (and otherwise manipulated) from Cygwin. It can also be deleted from the Windows Command Prompt by prefixing its full path with "\\?\".