Converting Video to FLV Files

Dawn PedersenAmerican River College

IntroductionThis will be a brief overview of using video in

Flash.We will cover the following topics today:

Streaming Video: an AnalogyVideo FormatsUsing the Adobe Media EncoderPlaying an FLV in Flash CS4

IntroductionWe will not cover the following topics; I

encourage you to research these on your own:Using FLVPlayback ManuallyPlaying Video Using ActionScriptAdding CaptionsUsing Alpha Channel VideoGoing Full ScreenEmbedding Video into an SWFAdding Cue Points

IntroductionPrepare for the upcoming tutorial by

downloading Rabbit.zip from here—it’s 63MB, so start now:http://blulob.com/ai/df2254/docs/Rabbit.zip

Unzip/Extract Rabbit.mov from the Rabbit.zip file.

Video FormatsThe first step in the process of creating the

FLV file that will be used in the Flash movie is to convert an existing video to the FLV format.

You will be working with digital videos that may include the following formats:AVI (Audio Video Interleave) – a Windows formatDV – the format used when video moves

directly from a video camera to the computerMPG/MPEG (Moving Pictures Expert Group)MOV – the QuickTime format from Apple

Video FormatsThese are the three output formats available

to you:FLV – the common format found on the web,

playable on Flash Player 6 and higher.F4V – developed to manage HD files for use in

Flash Player 9.0.115.0 or higherH.264 – a common format better known as

MPEG-4 or MP4You will need an FLV file if you want to use the

Dreamweaver/Flash player.

Encoding an FLVOpen the video in the player of your choice

and watch the video twice.The first time, just enjoy the video.The second time, ask yourself the following:

Is there a lot of movement in this video?Is the audio of major importance?Is there a lot of color in the video?Is the video in focus, or are there areas where

the image becomes pixelated?The answers to these questions will determine

your approach to encoding the video.

Encoding an FLVOpen and watch Rabbit.mov twice now.

It’s a little over 4 minutes long.In class, I’ll play it on the big screen for

everyone at once.Yes, the file is huge—over 70MB.When creating Flash video, you need every bit

of information contained in the video when you do the conversion.

Using the Adobe Media EncoderTo encode video, you use the Adobe Media

Encoder (rather than Flash.)1. Open the Adobe Media Encoder, found here:

PC: Start Menu > All Programs > Adobe Design Premium CS4* > Adobe Media Encoder CS4

Mac: Hard Drive\Applications\Adobe Media Encoder CS4

*The exact title here will depend on what version of CS4 was installed.

Using the Adobe Media Encoder2. Open Rabbit.mov in Adobe Media Encoder:

1. File > Add2. Navigate to Rabbit.mov3. Click on Open

3. Leave the Format dropdown set to FLV/F4V.4. Click the Preset dropdown arrow and select FLV –

Match Source Attributes (High Quality)5. Click the Preset dropdown arrow again, and

select Edit Export Settings… at the bottom of the list.

6. Click the link for Output File and select your destination.

Using the Adobe Media EncoderIn the Export Settings window, you will see a

preview area on the left and a settings on the right.

If you are in Simple Mode, you will see a circle button with two arrows pointing down.

7. Click it to jump to Advanced Mode for this exercise—the two arrows point up.

Using the Adobe Media EncoderBelow the preview area is a timeline.

You can scrub across the timeline here and set IN and OUT points.

You can also set cue points, which we will not cover today.

Using the Adobe Media Encoder8. Click on the Video tab on the right.

Codec: also mentioned in the audio lecture, the Codec reduces the data rate while maintaining image quality. Set this to On2 VP6.

Encode Alpha Channel: for use only if the video contains an alpha channel (for example for use with a green screen). Deselect it for our video.

Resize Video: videos should be resized in video software such as Adobe Premier, not here. Deselect it.

Using the Adobe Media EncoderFrame Rate: means frames per second. A

good rule of thumb is to choose a rate that is half that of the original file. For our example, set Frame Rate to 15.

Bitrate Encoding: CBR (constant bitrate) is for streaming video services such as Flash Media Server 3. VBR (variable bitrate) is for regular web servers using the HTTP protocol. Select VBR.

Using the Adobe Media EncoderEncoding Passes:

One pass is for videos with few bitrate changes. The video analysis and encoding are done at the same time.

Two passes is for videos with numerous bitrate changes. For example, at one point a narrator may stay put, but the next scene has race cars roaring by. In the first pass, the encoder analyzes the video for major changes. In the second pass it encodes the video to accommodate those changes.

Select Two.

Using the Adobe Media EncoderBitrate [kpbs]: The slider sets the bitrate for

the video portion of the encoding. This is where your job is like the Hoover Dam operator: If you set this too high, the residents downstream

will have a bad day. You cannot supersize the quality—you will end up

with the same quality as the original and a much larger file.

The data rate for an FLV is the sum of the audio and video data rates.

For novices, a good target is 350 kbps. Set the video bitrate to 300 kbps.

Using the Adobe Media EncoderSet Key Frame Distance: this is in the

Advanced are for a reason. Leave this unselected until you master video compression.

Key Frame Interval: will appear only if Set Key Frame Distance is selected. This will depend on how much action is going on. Video of paint drying would work with one keyframe

for every 300 frames. Video of a race car in motion would work with one

keyframe for every 30 frames.

Using the Adobe Media Encoder9. Click on the Audio tab to change audio

settings. You need to make two decisions here:

Stereo or mono?What will the data rate be?

10.Stereo or Mono: unless you are encoding your band’s video, stick with mono. Also, if you are starting with mono, you cannot improve sound quality by selecting stereo—it will only increase file size. Select Mono.

Using the Adobe Media Encoder11.Bitrate Settings: for Bitrate [kbps], you

should generally choose 48 or 64.Anything higher only serves to increase

demand on the bandwidth.Anything lower results in an increasing

degradation of audio quality. Still, 32 will work if the soundtrack is nothing more

than a voice-over. 16 is ideal if the soundtrack is composed of

intermittent sounds like frogs.Set the Bitrate to 64 for our video.

Using the Adobe Media Encoder12.Click OK to return to the render queue.13.Click the Start Queue button to stat the

render process.14.You will see the progress bar move across

the screen as the video is being rendered.15.When the encoding is complete, a green

check mark will appear in the Status area.16.When you see the green check mark, close

the Adobe Media Encoder and check out the file size of the resulting FLV file.