Archive for the ‘video’ Category

Making DVD File Systems

December 30, 2010

If you have a VIDEO_TS folder, which is the files to make a video DVD, and you’re using a Mac, how can you create a playable DVD? There are a couple of free programs I like for this.

Both iDVD and DVD Studio Pro, among other programs, can create video DVD title set files (VIDEO_TS folders), but those need to be burned to DVD in a special format (called UDF 1.02). To make a playable video DVD, you can burn a VIDEO_TS folder to DVD using the program LiquidCD. Or you can create an ISO image file with the program AquaISO. Later you can burn the ISO file to a DVD using LiquidCD, Disk Utility, SimplyBurns, or other programs (including a bunch on Windows).

Why would you want to save a VIDEO_TS folder or ISO file on a hard drive instead of burning a DVD directly from iDVD or DVD Studio Pro? Several reasons. It’s a convenient way to burn multiple copies. It’s a way to keep an archive copy in a compact format. You might need to copy or send it to other people so they can burn it to DVD. You might need to make changes to the files before burning them to DVD, using a program such as MyDVDEdit (such as to work around iDVD bugs in handling 16:9 videos). You might have created the VIDEO_TS folder using some other software or gotten it from someone else. You might want more control over the burning process, such as burning at a lower speed for higher quality (DVD Studio Pro doesn’t let you control the burning speed).


From Flash to MP4

May 25, 2010

I’ve been thinking about saving some Flash videos from YouTube, Vimeo (videos without a download link), and other sites for playing on iPods and other platforms that don’t support Flash video. Since most Flash video these days uses the h.264 codec, it should be possible to de-multiplex the .flv file to extract the video and audio streams, then re-multiplex them into an MP4 container, with no re-encoding.

On a Mac with Perian and QuickTime Pro installed, just open the .flv file in QuickTime Player 7, do “Save As,” choose “self-contained movie,” and after a few seconds, you’ll get a copy of the video in a QuickTime .mov file.

There’s also a more roundabout way to do it on Windows, if you really want a .mp4 container file.

  1. Download the Flash video file (.flv extension). The Firefox add-on DownloadHelper is one way to do this. You should probably download the highest-resolution version available.
  2. Run FLV Extract and drop the .flv file onto it to create .264 and .aac files, which contain the video and audio respectively. If it produces files with different extensions, your Flash video file isn’t encoded in h.264 so the next step won’t work, sorry.
  3. Run YAMB and add the .264 and .aac files to re-multiplex them into a .mp4 file.
  4. Play the .mp4 file and check that audio and video stay in sync before you delete the .flv file.

Electronic Image Destabilizing

January 21, 2010

Do you understand all the automatic settings on your electronic equipment? Recently, I was reminded to not assume that the current settings are appropriate, when one of them did the opposite of what it was supposed to.

I was shooting video of a mini-conference in which a lot of the footage was of one person at a time standing and speaking behind a podium, in front of a white board. The camera was a Panasonic consumer MiniDV camcorder that was bought several years ago on a budget (it wasn’t mine). I was using a tripod and did a lot of head-to-waist shots with occasional zooms or pans when the speaker got close to the edge of the frame.

Fairly often, the shot would jerk somewhat up and down again, as if the tripod head were loose and shaking. It was a consumer-level video tripod (a Velbon), but I thought I had tightened the pan/tilt head about right to prevent slipping. I fiddled with it a few times, then started looking through the camera’s setup menus. There was an icon on the LCD that said “EIS”, so I looked up what that meant, since I understood all the other information on the screen.

I found out that “EIS” means Electronic Image Stabilizer. With it on, the camera analyzes the image and when it detects something moving up and down rapidly, it concludes that there is camera shake occurring, so it shifts the image in the other direction to compensate. It’s a poor man’s Steadicam for hand-held shots.

But the EIS backfired on my tripod-mounted shots. Whenever one of the speakers would wave his arms up and down to emphasize a point, the camera would lock on to the arms and try to keep them stationary, moving the podium and white board up and down instead! So it destabilized my stable shots.

I turned off the EIS, and my shots were stable for the rest of the event.