wiki:FramerateGuide

Framerate Guide

General

FPS, or Frames Per Second, is a count of how many pictures a movie displays per each and every second.

A frame is a still, visible image. Showing these frames in succession creates the illusion of a motion picture.

Different content has different numbers of FPS.

The different FPS counts can be classified by the part of the world the DVD is from, the way the content was recorded, or the way the DVD was mastered.

Setting FPS in HandBrake

In the main window, on the Video tab, there is a pop-up menu labeled "Framerate (fps)". It lets you select the frame speed you desire.

The default selection, "Same as source," doesn't alter the times used by the input video.

What does "Same as source" do?

"Same as source" uses the same time stamps as the input video source. So PAL will come out at 25fps, NTSC video at 30, and NTSC Film at 24.

This means you don't have to worry about setting it for anything.

However, understand that DVDs and other MPEG-2 video streams use inherently variable framerates. This means that the actual framerate is not a steady number. This doesn't matter in most cases--for example, iPods handle it well. But if you find that playback is jerky, you might want to experiment by specifying a particular framerate instead of using "Same as source."

If you work with high definition content for the AppleTV, keep in mind that the device doesn't support frame rates higher than 25 at 720p, so you may need to downscale the picture to a height of 540 pixels in order to deal with 30fps content.

PAL vs. NTSC

If you have ever purchased a DVD in Europe and not been able to play it in America, even on a region-free DVD player, you know what this section is about.

The big difference is that PAL DVDs are encoded at 25fps, while NTSC DVDs are encoded at 30fps. Also, PAL DVD frames are larger: 720*576 as opposed to 720*480 for NTSC.

If you use both PAL and NTSC DVDs, you want to use the "Same as source" selection from the "Framerate (fps)" pop-up menu. This will autodetect which format the DVD uses.

"NTSC" stands for National Television Standards Committee. NTSC DVDs are sold in the United States and other countries it deals closely with (Canada, Mexico, the Philippines, Japan, South Korea, etc).

"PAL" stands for Phase Alternating Line. PAL DVDs are sold in Germany, the United Kingdom, France, much of the rest of Europe, much of South America, Australia, China, India, Pakistan, and large parts of Africa.

PAL and NTSC are really competing television standards. A "PAL DVD" or an "NTSC DVD" is just a DVD designed to play back on a TV adhering to either of those standards. So be careful googling--you will find much info that is not relevant to DVDs.

But wait...NTSC DVDs are 30fps? Aren't movies 24fps? How does that work?

NTSC film vs. NTSC video

There are two types of NTSC content: NTSC film, and NTSC video. Video is generally interlaced while film is usually progressive.

NTSC video is 30fps. This is what you get on TV.

Most movies aren't recorded at 30fps, and neither are most modern TV shows. They're done at film speed: 24fps.

24fps or 23.976? 30fps or 29.976?

This guide has used 24fps for NTSC film and 30fps for NTSC video. This is because it's simpler and takes less time to write. However, it's not really precise.

Back in the day, NTSC TV video was indeed 30fps. However, video hasn't "really" been 30fps since color TV broadcasts started. Before them it was 30000 frames for every 1000 seconds. But to accommodate the extra color information, the rate was very slightly dropped by stretching the frames to cover an extra second for every 1000 seconds, making it 30000/1001.

30fps == 30000/1001 == 29.97fps

24fps == 24000/1001 == 23.976fps

Use the more precise decimal form when you're telling HandBrake or any other piece of software what to do.

Other Resources

Last modified 8 years ago Last modified on 11/09/08 22:12:31