7.2. Converting Prerecorded Materialto FLV Format
It's not very likely that all of the audio/video
material you want to stream to your users was recorded by your
FlashCom Server. Chances are, you'll have content
that you've recorded with other higher-quality
capture sources, such as a mini-DV camcorder or video output from 3D
modeling applications. Your business clients may even provide you
with high-quality video footage for movie trailers, sports or news
clips, or product demonstrations. Most of these files are not going
to be in a digital video format directly supported by FlashCom. For
that reason, you'll need a way to convert disparate
video formats to the FLV file format, the only one that
FlashCom supports.
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If you need some sample video content to convert to FLV files, you
can download sample Windows AVI and QuickTime MOV files from the
book's web site.
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7.2.1. Recompressing Video Files
A sure sign of a less than ideal digital video workflow is the act of
recompressing digital video files that have already been
significantly compressed with some other encoder. For example, a
business client of yours may provide you with Windows Media (WMV)
files. Since FlashCom supports only the FLV file format,
you'll need to convert the WMV files with one of the
utilities discussed in this section. However, WMV files already have
been compressed from some other source footage. It's
likely that the WMV files already show signs of compression, such as
artifacts (digital noise around the edges of video images). Applying
yet another compressor such as Sorenson Spark to this footage will
only introduce more artifacts. So you should always attempt to get
the original source videotape (or transfer) and capture the video
yourself in your preferred video editing application. Alternatively,
ask your client to provide you with broadcast-quality digital
video
files.
7.2.2. Using Flash MX 2004 to Create FLV Files
You may already know that Flash MX and Flash MX 2004 enable you to import and
embed digital video files into Flash movies (SWF files). But did you
know that you can also reexport those embedded video files as FLV
files that you can use with FlashCom Server? Admittedly, the Flash MX
or Flash MX 2004 authoring environment can encode video only with the
Sorenson Spark Basic edition codec (a.k.a. CBR encoding). Thus, the
quality of video is significantly lower than that of the other tools
we discuss in this section. The quality is good enough, though, if
you just need a quick conversion of video formats to use in a
FlashCom Server application.
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If you have Flash Pro, you can use the included FLV Exporter tool
with most QuickTime-enabled applications, including Apple QuickTime
Player Pro. This utility is discussed in the next section.
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The following tutorial provides an overview of the Video Import
Wizard in Flash MX 2004. For more specific information on the options
available in the Video Import Wizard, refer to the Help panel in
Flash MX 2004.
To import a digital video file into a Flash MX 2004 document:
Before you begin, make sure your Flash document is using the frame
rate you want to use with the video clip from FlashCom. With a new
Flash document (FLA file) open, choose
Modify Document (Ctrl-J or
Cmd-J). In the Frame Rate field, enter your desired frame rate. Most
video delivered over the Internet uses a frame rate of 12, 15, or 24.
Click OK to close the dialog box. Choose File
Import Import to Library.
In the Import to Library dialog box, browse to a digital video file
that you want to encode in FLV format. Flash MX 2004 supports most
popular video file formats, including QuickTime (MOV), Video for
Windows (AVI), Windows Media (ASF, WMV), and MPEG files. After you have selected a digital file to import, the Video Import
Wizard appears. The first screen of the wizard will vary according to
the file format you chose. Figure 7-2 shows the
first screen when a QuickTime file has been selected for import. If
you want Flash MX 2004 to convert the file to the FLV format, choose
the Embed Video in Macromedia Flash Document option and click the
Next button.
After you have selected the QuickTime embed option (or if you have
selected a non-QuickTime file format in Step 2), the Video Import
Wizard proceeds to the Editing phase. As shown in Figure 7-3, you can decide whether you want to import the
entire video or choose various clips within the source footage to
import. For the purposes of this exercise, choose the Import the
Entire Video option, and click the Next button.
 Now you have reached the Encoding phase of the import process. On
this screen, shown in Figure 7-4, you can choose
the compression and filter options for the clip. You can choose a
predefined compression profile for your desired bit rate, or you can
create a custom profile by choosing Create New Profile from the
Compression Profile drop-down menu. For the purposes of this
exercise, choose the DSL/Cable 256 Kbps profile. If you click the
adjacent Edit button, you can see the options for profiles and the
specific settings for this preset on the Compression Settings screen,
as shown in Figure 7-5. After you review these
settings, click the Back button to return to the main Encoding
screen. Select Create New Profile from the Advanced Settings
drop-down menu. This brings up the Advanced Settings screen, as shown
in Figure 7-6, where you can change color
characteristics of the video image, scale and crop the video area,
control how the clip is imported into the current timeline, and
enable/disable the audio track of the video clip. Click the Back
button to return to the main Encoding screen.
 Once you have determined the compression and filter settings for the
clip, you're ready to let Flash MX 2004 encode the
digital video file. In the Video Import Wizard, click the Finish
button. As Flash encodes the video, a dialog box indicates the
progress of the import as shown in Figure 7-7.
 To export the embedded video clip to an
external FLV file: After the video clip has been imported into the Flash document, open
the Library panel (Ctrl-L or Cmd-L). Right-click (or Ctrl-click on
Mac) the Embedded Video symbol that represents the video file you
imported and choose Properties as shown in Figure 7-8.
 In the Embedded Video Properties dialog box, shown in Figure 7-9, click the Export button. In the Export FLV
dialog box, specify the name of a new FLV file and click the Save
button.
 Move the FLV file to the streams/_definst_
folder of your FlashCom application.
If your FlashCom applications folder
doesn't have a streams
subfolder, refer to "Configuring the FCS
Application" later in this chapter. There, you will
learn how to create the appropriate folders in which to store your
FLV files.
7.2.3. Exporting Video from QuickTime Player Prowith the FLV Exporter
If you are using Flash Pro, your installation CD or downloaded
installer files include a
Flash_Video_Exporter.exe file (or
Flash_Video_Exporter.dmg on
Mac). Make sure that
you have run this installer file before continuing with this section.
This installer does not create a standalone application with which
you can encode digital video files. Rather, it installs a QuickTime
plugin that enables FLV export from most QuickTime-enabled
applications.
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In January 2004, Macromedia released Video Update 1.2 for Flash Pro.
This updater improves the capabilities of the
Flash Video Exporter. Among other
features, the updater adds two-pass VBR encoding to the
exporter's options and embeds the length of the
video clip into the FLV file for use by the media components,
discussed later in this chapter. You can obtain the updater from
http://www.macromedia.com/support/flash/downloads.html.
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A good indication that your preferred video editing application
supports QuickTime is to check for a
File Export Movie option.
Usually, the Export Movie option of a video application enables you
to output QuickTime files. Some video applications such as Adobe
Premiere Pro 7 support QuickTime files but do not have a feature to
export movies in various encoders like the FLV format.
In order to export FLV files from Apple QuickTime Player, you need to
buy a registration key for the Pro version. You can find more details
about QuickTime Pro at http://www.apple.com/quicktime/upgrade.
The primary difference between Flash Pro's Flash
Video Exporter and the built-in Video Import Wizard of
Flash MX 2004 is VBR encoding. The
Video Import Wizard can compress video only with CBR encoding, while
all of the other tools discussed in this chapter support VBR
encoding. As you learned earlier, you can achieve better visual
images and smaller file sizes if you use VBR encoding.
To export the video in FLV format from QuickTime Pro:
Open the digital video file in QuickTime Pro. Optionally, drag the in and out markers (the small triangles below
the progress bar, shown in Figure 7-10) to trim the
clip. Be sure to choose
Edit Trim after you have
changed the markers' positions.
 Choose QuickTime's
File Export Movie command.
In the Save Exported File As dialog box (Figure 7-11), choose Movie to Macromedia Flash Video (FLV)
in the Export drop-down menu. Specify a location and filename for the
new FLV file. Click the Options button in the dialog box to view and
edit the compression settings to be applied by the Flash Video (FLV)
Exporter, as shown in Figure 7-12.
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Unless you've got to be somewhere in a hurry, always
use the Best (2 Pass) option for compressing your FLV files. The
visual quality and file size are always better, compared to other
compression options.
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After you have determined which compression settings
you'd like to use, click the Save button to begin
the export process. QuickTime shows the export progress in a dialog
box. (We discuss appropriate settings throughout the remainder of the
chapter.) When the FLV file has finished exporting, copy the file to the
appropriate streams folder of your FlashCom
application, as described under "Configuring the FCS
Application" later in this chapter.
7.2.4. Optimizing Media with Sorenson Squeeze
One of the first products on the market to create FLV files was
Sorenson Squeeze. Naturally,
Sorenson would have an edge on the competition, given that they
created the Spark codec. By far, Sorenson Squeeze gives you the most
control over the subtleties of compression with the Spark Pro codec.
You can also batch process several files with the same settings or
even choose multiple output settings for the same file. For example,
if you want to create FLV files for specific bit rates, you can add a
new output setting for each bit rate you wish to create. You can also
capture DV (Digital Video) footage directly from your
Firewire-connected camcorder with Sorenson Squeeze. In this section,
we provide you with an overview on the media creation process in
Squeeze. To learn more about Sorenson Squeeze, visit http://www.sorenson.com.
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Sorenson Squeeze is offered in two editions for Flash users:
Sorenson Squeeze 4.0 for Flash MX
(which, despite the name, is also appropriate for Flash MX 2004) and
Sorenson Squeeze Compression 4.0
Suite. The Compression Suite enables you to compress video in several
output formats, including MPEG-2 DVD video to Flash Video (FLV). The
Macromedia Video Kit includes Sorenson Squeeze 4.0 Lite for Flash MX,
which has a reduced feature set from Squeeze 4.0 for Flash MX. You
can find a comparison of features at http://www.macromedia.com/software/studio/flashvideokit/sorenson_comparison.html.
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The figures in this section depict the Compression Suite version, but
the features discussed are available in both editions. While you can
also use Squeeze to output Flash movies (SWF files), this section
discusses only FLV output.
To export FLV files from Sorenson Squeeze 4.0:
Open the Sorenson Squeeze application. Choose File Import Source
(or click the Import File button in the Input panel), and browse to a
location containing a digital video file. When the video clip opens in Squeeze (see Figure 7-13), you can preview the video clip and choose in
and out points for the clips if you need to trim footage from the
original clip. Squeeze 4.0 offers a new cropping tool, available
directly in the preview window.
 If you want to adjust the image contrast or brightness or make other
audio/video tweaks, you can use one of the presets available in the
Filters panel (shown on the left in Figure 7-13) or
create your own by choosing
Filter New or clicking the
plus (+) button in the toolbar of the Filters panel. As shown in
Figure 7-14, the Filter dialog box provides image
adjustment controls. Any changes to the Contrast, Brightness, Gamma,
White Restore, Black Restore, or Cropping values update the video
clip image in the preview window of the main application interface.
You can control the video clip's current position
while you edit the image adjustment values. While most of these
filters' effects can be previewed immediately, the
benefits of some filter settings cannot be appreciated until you have
actually compressed the clip: Video Noise Reduction This setting can be used to eliminate grainy looking video. Video
noise is usually found in footage shot in low light, with an
inexpensive mini-DV camcorder or footage transferred from VHS tape.
As a rule of thumb, use the Light setting for footage captured from a
low-end mini-DV camcorder (i.e., a single-chip or CCD camcorder) and
use the Heavy setting for VHS transferred footage. Normalize Audio When selected, option analyzes the audio track of the video clip and
looks for the highest audio level. If that audio level is very low,
Squeeze will amplify it to a
"normal" level and adjust the rest
of the audio track accordingly. For example, if your DV
camcorder's microphone was pointing at a person
lecturing from a podium and that person's voice
wasn't very loud (relative to the
microphone's position), normalizing the audio can
increase the volume so that it's more audible.
However, normalization usually increases background noise and silence
in audio gaps as well.
 If you created a custom filter, select Custom in the Filters panel
and click the Apply button. The selected filter is now added to the
current clip in the Job list below the video preview area, as shown
in Figure 7-13. Now you're ready to select the output format. Expand
the Macromedia Flash Video (.flv) listing in the
Format & Compression Settings panel, as shown in Figure 7-15. Choose the bit rate settings for your target
audience; you can Shift- or Ctrl-click as many bit rate settings as
you require. For footage that you want to use with FlashCom Server,
start with one of the bit rates ending with the _Stream suffix. For
this example, we selected the 256K_Stream option. After you have
selected a bit rate, click the Apply button. The output setting
appears below the clip name in the Job list, as shown in Figure 7-16.
 You can use the default compression settings that Squeeze has
predefined in the output profile, or you can adjust the settings to
suit your tastes. Click the + button next to 256K_Stream in the Job
list, and you will see the expanded output setting shown in Figure 7-17. Double-click either the MP3 or Spark Pro list
item. Double-clicking either opens the Audio/Video Compression
Settings dialog box shown in Figure 7-18. Again,
while the VBR compression process takes longer than CBR,
you'll get better visual quality in your video clip
if you choose Sorenson 2-Pass VBR in the Method combo box, located in
the Video section of this dialog box. Among other compression
options, you can also provide Squeeze with a file size limit (in the
Constrain File Size field). If your desired compression settings
exceed this limit, Squeeze will reduce the quality to meet your file
size expectations.
 Once you have finessed the output settings, you're
ready to let Squeeze do its job. Click the Squeeze It! button, as
seen in Figure 7-17, and Squeeze starts to analyze
the video clip and compress it in FLV format. The resulting FLV file
is located in the same directory as your original video clip, unless
you specified a different output location. You can change the output
location by selecting the output setting in the Job list and choosing
Batch Change Destination.
You can also right-click (or Ctrl-click on Mac) the output setting
and choose Change Destination. After Squeeze has finished creating the FLV file, copy the FLV file
to the appropriate streams folder of your
FlashCom application.
If you want to compress two or more source video clips in a batch,
you can continue to import more source files using
File Import Source or
clicking the Import File button. Select the new clip in the Job list,
and choose your filter and compression options. Repeat the process
for each additional source clip. You can also select multiple output
settings for each individual clip. When you have all of your source
clips and output settings configured, click Squeeze It! to begin
processing the batch.
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One of the great features of Sorenson Squeeze is its capability to
batch compress several video clips in the same location. Moreover,
Squeeze will continue to monitor that folder for new video clips and
compress them automatically. The process to batch compress and/or set
up a watch folder is nearly the same as the steps outlined in the
previous section:
Move all of your video clips to the same folder location (such as
C:\video_compress).
In Sorenson Squeeze, choose
File Watch Folder (or
click the Watch Folder button), and select the location you used in
Step 1. The video preview area will not display any video footage,
but the Job list will list the folder's name.
Proceed to choose output file format(s), filter settings, and
compression options.
After you choose a compression option, the Job list displays the
option's information. Note that the output filename
includes the compression setting name as a suffix that will be added
to each source video clip's filename. For example,
if you choose the 256K_Stream preset, a source clip named
snail.mov will have a counterpart output
filename of snail256K_Stream001.flv.
Click the Squeeze It! button, and Squeeze will begin compressing the
files in the folder location. At this point, Squeeze creates two
subfolders in the watch folder location:
CompletedSource and
CompressedOutput. After Squeeze has finished
compressing a source clip in the watch folder location, it moves the
source clip to the CompletedSource folder. The
compressed FLV file for each source clip is created in the
CompressedOutput folder.
After Squeeze has finished compressing the original source clips in
the watch folder location, it continues to monitor the folder for new
source clips as long as the Squeeze application runs. As new clips
are added, Squeeze creates new output files with the compression
options you specified earlier.
You can create a virtual directory in your FlashCom virtual host
settings that is mapped to the CompressedOutput
folder of the watch folder, or you can create a script that moves the
compressed files to another location. For example, you could move the
compressed files using the <cfschedule> tag
in a ColdFusion page. In this way, you can stream new files from
FlashCom applications without additional intervention.
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7.2.5. Creating Media with Wildform Flix Pro
You can also encode FLV files with Wildform Flix Pro. Nearly all of the
features in Sorenson Squeeze 4.0 are available in Flix Pro 4.0. Flix
Pro does not have a watch folder as Squeeze does (see the sidebar),
but Flix can batch process files with a few extra filenaming options.
Flix Pro version 4.0 is currently available only for Windows; the
latest Macintosh version is 3.0.
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Flix can also create vector versions of your digital video source
clips, as Flash movies (SWF files). These movies cannot be streamed
from a FlashCom application, but they can be used to create
frame-by-frame masks for Flash video. To see a sample of vector
output from Flix, go to http://www.wildform.com/resources/gallery_vv.php.
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To export an FLV file from Flix Pro 4.0:
When you start Flix Pro 4.0, the File tab, as shown in Figure 7-19, is visible. Click the Browse button to the
right of the Input setting to select a source clip. Flix will
automatically assign an output file in the same location, with the
file extension of the output format you are using. such as
.flv or .swf. By default,
Flix assumes you are outputting to a .swf file,
so change it to .flv.
 Choose a compression profile in the Preset drop-down menu. For this
example, choose the 300K Broadband Video (MX FLV) profile, as shown
in Figure 7-20.
 If necessary, click and drag the in and out pointers below the video
preview area. The selected range is shaded blue (which appears gray
in Figure 7-21).
 Click the Video Filters button in the lower right corner of the File
tab. The Editor dialog box (shown in Figure 7-22)
offers similar options to the filter settings of Sorenson Squeeze.
Unlike Squeeze, though, you can finesse the video noise reduction
with a precise numeric slider. You can also boost saturation values;
NTSC video (the video signal recorded to DV camcorder tape) often
appears less saturated when viewed on a computer monitor compared to
a standard TV screen. You can use the Saturation slider to revive
footage that looks washed out. Or you can remove all saturation to
create black-and-white (grayscale) video. You can also check the
Deinterlace option to remove the flicker from NTSC video footage shot
with North American camcorders. While Sorenson Squeeze will
automatically detect that your footage is interlaced, you need to let
Flix know if you want your footage deinterlaced.
 If you'd like to finesse the video and audio
compression settings for your chosen preset, click the Vid/Aud tab
(shown in Figure 7-23). One of the nice features of
Flix is that the original source (or input) clip's
information is juxtaposed next to your output clip settings. You can
easily determine whether you're specifying an output
dimension or audio sampling rate that exceeds the
originalgenerally, you do not want to upsample video or audio
quality in your output file.
 Now you're ready to output the FLV file. Select the
File tab and click the Encode button to the right of the Preset
option, as seen in Figure 7-21. Flix opens an
Encoding dialog box (as seen in Figure 7-24)
enabling you to monitor the bit rate settings during analysis and
compression.
 When Flix has finished the encoding process, a preview window appears
and plays the FLV file. If you missed the playback of the preview,
you can replay the FLV file by clicking the Play button to the right
of the Output setting of the File tab. Copy the FLV file to the appropriate streams
folder of your FlashCom application.
If you want to encode several source clips with the same preset,
choose Edit Batch Process
to select the clips.
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For an open source solution to FLV
compression, try
ffmpeg,
which uses libraries of audio and video codecs to transcode digital
audio and video formats. FLV is among the many formats that the tool
recognizes. The ffmpeg utility can also capture
and create live streams. For more information on this handy utility,
visit http://ffmpeg.sourceforge.net. For more
information on open source programming in general, go to http://opensource.org.
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