Last updated: January 23, 2014

 

Index

  1. Introduction
  2. Quick workflow
  3. Selecting and opening a video clip
  4. Scanning video for faces

         Interval
         Border
         Detecting faces

  5. Examining face screenshots

         Count labels
         Deleting frame shots
         Saving frame shots
         Saving time code
         Printing out timecode

  6. Using Player

         Setting export folder
         Selecting export format
         Taking sceenshots

  7. Preferences

         7a) General settings
         7b) Folders
         7c) Export

  8. FAQ


 

1. Introduction: Imagine examing a security video to find suspicious individuals.  Spotting human faces on a long video clip can be a tedius task.  Look4Faces is a desktop application that lets you scan a QuickTime-readable video clip (M4V, MOV, MP4) to find frames containing faces.  As a result, Look4Faces will list all frames with one or more faces.

 

Mac software Look4Faces

Screenshot 1-01

 

Look4Faces comes with a built-in video player.  And you can click on a particular screenshot with faces to locate the exact frame over the video player.

 

Mac software Look4Faces

Screenshot 1-02

 

2. Quick workflow: Look4Faces's workflow goes as follows.

 

  1. Choose Open Video under File to select and open a video clip.
  2. Set an interval from the drop-down menu located at the bottom-left corner.  And select a border size from the other drop-down menu.
  3. Choose Find Faces under Picture to scan the selected video clip.
  4. Choose Open Pictures Window to open Pictures, which populates all frames with one or more faces.
  5. Click on a screenshot over Pictures.  Then choose Export under File to save that screenshot as an image file.  Or click on one or more screenshots and then choose Export Selected to save all selected screenshots.
  6. Show Player under Player to open a video player.  Click on a screenshot over Pictures to locate the corresponding frame over the video clip.

 

3. Selecting and opening a video clip: The first thing you need to do is select and open a video file to work with.  Look4Faces is able to read limited types of QuickTime-compatible media containers including M4V, MOV, MP4.  Choose Open Video under File or click on the second toolbar button from the left end, you will be prompted to select a file.  (See Screenshot 1-01.)  Moreover, if you have quick access to a video clip, you can use a dropbox.  Choose Open Video With Dropbox under File or click on the third toolbar button from the left.  Then drag and drop a video clip onto the dropbox window.  (See Screenshot 1-02.)

 

Mac software Look4Faces

Screenshot 1-01

Mac software Look4Faces

Screenshot 1-02

 

When Look4Faces successfully reads the video file you've selected, it will take a screenshot at a frame near the end, which will appear at the center.  (See Screenshot 1-03.)  Appearing right below the screen window are three text fields, showing numbers.  The first field next to the Duration label indicates the movie duration in terms of the total number of seconds.  The second field also shows the movie duration but in terms of timecode.  The field to the right indicates the movie frame rate.

 

Mac software Look4Faces

Screenshot 1-03

Mac software Look4Faces

Screenshot 1-04

 

4. Scanning video for faces: Scanning video to find frames containing faces requires you to configure two settings.  The first setting is time interval.  Look4Faces does not scan every frame to find frames containing faces.  So you must tell Look4Faces how frequently you want it to scan video.  As shown in Screenshot 1-04, explore the drop-down menu at the bottom-left corner.  If you choose 1/4 of a second, for example, Look4Faces will extract a picture frame every 0.25 second over the entire duration to see if that frame contains one or more faces.

 

Mac software Look4Faces

Screenshot 1-05

Mac software Look4Faces

Screenshot 1-06

 

The other setting for you to configure is border.  If you explore the drop-down menu at the bottom-right corner, you should find about a dozen selections.  (See Screenshot 1-05.)  But what for?  In reference to Screenshot 1-06, consider a case where a frame contains a face that is positioned near the edge.  The OS X framework (a collection of libraries) responsible for detecting faces over a picture is Core Image.  More specifically, a class called CIDetector will tell the application how many faces a picture contains.  This procedure can fail if a face is located near the edge.  What Look4Faces do is border each frame to somewhat increase the likelihood of detecting near-the-edge faces, telling CIDetector where clear boundaries are.  Now, shown under the drop-down menu at the bottom-right corner are border sizes.  If you choose 20 points, for example, also assuming that you have a video size of 480 x 360 pixels, then Look4Faces will create a 520 x 400 px (for non-retina screen) background picture in white.  And the application will insert each frame at the center of this background picture and then scan for faces.  The higher the number of points you choose, it will cost you more as a rate of productivity.  If you choose No border, Look4Faces will proceed without framing each picture.

When you configure interval and border, provided that you have already selected a video clip, a toolbar button with three color faces will become active.  Click on this toolbar button or choose Find Faces under Picture to let Look4Faces begin scanning the video file.  Then a modal sheet with a progress bar will appear.  It can be a time-consuming task.  You can abort it at any time by clicking on the Abort button.  When it finally finishes scanning the video clip, you will see a blue label at the bottom of the application window.  (See Screenshot 1-08.)  It will disappear in 5 seconds.  Additionally, you will be notified of completion by a soft, short chime-like sound.

 

Mac software Look4Faces

Screenshot 1-07

Mac software Look4Faces

Screenshot 1-08

 

5. Examining face screenshots: After Look4Faces finishes scanning the selected video clip, we should find out which movie frame contains what faces.  Let's open Pictures by choosing Open Pictures Window under Picture.  You can also click on the fourth toolbar button from the left end for the same purpose.  A separate window will appear, giving you a collection of small pictures.  (See Screenshot 1-09.)  They are all movie frames.  Every picture is named after its frame position in terms of timecode.

 

Mac software Look4Faces

Screenshot 1-09

Mac software Look4Faces

Screenshot 1-10

 

Now, let's quickly shift our attention back to application's toolbar menu.  There are two color-filled cirlcles to the right.  The one in orange indicates the total number of screenshots with one or more faces that Look4Faces has extracted from the selected video file.  The maximum number this label can show is 999.  If it says '999+,' then you can place your mouse over it to see the exact number, which will appear as a tooltip.  The other counter (in yellow green) indicates the number of screenshots you have currently selected under the Pictures window.  If you select one frame shot and then press Command + A, then all pictures will be selected.  So you should see the same number on both counter labels.

Going back to Pictures, when you select a frame shot, its time position will be inserted to the field next to the Timecode label.  It should coincide with the name of the frame shot.  Appearing at the bottom-left corner is a larger screenshot.  This box can display a picture at 120 x 120 points maximum.  If necessary, try using the horizontal slider to rescale all frame shots.

When you select a frame shot, you should see another count label.  It appears in blue.  It indicates the number of faces that Look4Faces has detected over the selected frame shot.

If you want to remove any of the movie frame shots, you can make a selection of screenshots and then press the Delete key.  Or choose Remove Pictures under Picture.  And you will be prompted for confirmation.  (See Screenshot 1-11.)  Similarly, choose Clear Pictures to remove all pictures.

 

Mac software Look4Faces

Screenshot 1-11

Mac software Look4Faces

Screenshot 1-12

 

So what do we want to do after scanning video for faces?  One thing that you can do is save one or more movie frame pictures.  If you want to save only one particular frame shot, select that one and then choose Export under File.  (See Screenshot 1-12.)  If you want to save more than one, then choose Export Selected.  Let's first talk about the Export command. 

 

Mac software Look4Faces

Screenshot 1-13

Mac software Look4Faces

Screenshot 1-14

 

Note that the Export command will become active only when you select just one frame shot.  When you choose it, you will be asked to select an export format.  (See Screenshot 1-13.)  So select one from the drop-down menu.  Then press RETURN or click on Next.  The next step is to name a file.  (See Screenshot 1-14.)  And you will get to set a compression rate at this phase if you have chosen JPEG or JPEG 2000 as an export format.  Screenshot 1-15 shows an example frame shot exported.  It's opened with Preview.  Note that Look4Faces will export frame shots at actual movie screen dimensions.

 

Mac software Look4Faces

Screenshot 1-15

Mac software Look4Faces

Screenshot 1-16

 

Speaking of Export Selected, this command will become active when you select one or more frame shots.  You don't necessarily select all side-by-side screenshots.  You can hold down the Shift key to select non-adjacent pictures.  (See Screenshot 1-16.)  Or select one and then press Command + A to select all frame shots.  Anyway, when you choose Export Selected, Look4Faces will first ask you to select an export format.  Next, you will NOT be prompted to name any of frame shots.  Instead, you will be prompted to select a location (volume or folder) where to save all frame shots.  (See Screenshot 1-17.)  If you proceed by pressing RETURN or clicking on the Open button, Look4Faces will create a folder named after this application plus a lot of numbers at the path you've selected.  And you will find your frame shots inside this folder.  (See Screenshot 1-18.)  Note that each frame shot will be named after its time position except that hours, minutes and seconds are separated by the hyphen, not the colon.  OS X does not allow the user to use the colon to make a file name.

 

Mac software Look4Faces

Screenshot 1-17

Mac software Look4Faces

Screenshot 1-18

 

After scanning the selected video clip, what you can also do is save the timecode numbers of all frame shots as a text file (.txt) or an XML file (.xml).  To save timecode numbers as a text file, choose Save Timecode As Text under File.  (See Screenshot 1-19.)  Then you will be prompted to name a text file.  Screenshot 1-20 shows a text file as the result of choosing Save Timecode As Text.  You should find the same number of lines in the text file as that of frame screenshots under the Pictures window.

 

Mac software Look4Faces

Screenshot 1-19

Mac software Look4Faces

Screenshot 1-20

 

Similarly, if you choose Save Timecode As XML under File, you will be prompted to name an XML file.  (See Screenshot 1-21.)  Screenshot 1-22 shows an example XML file.

 

Mac software Look4Faces

Screenshot 1-21

Mac software Look4Faces

Screenshot 1-22

 

Addtionally, you can print out the same sort of timecode numbers.  Choose Print Timecode under File for this purpose.  (See Screenshot 1-23.)  Look4Faces will then send data to your System.  And you will see a printout screen as shown in Screenshot 1-24.  If you want to instead save data as a PDF file, choose Save as PDF from the drop-down at the bottom-left corner.

 

Mac software Look4Faces

Screenshot 1-23

Mac software Look4Faces

Screenshot 1-24

 

6. Using Player: Look4Faces comes with a built-in video player, which lets you take screenshots over the video clip you have selected.  In order to open the video player, choose Show Player under Player.  You can also click on the toolbar button next to the orange counter label.  (See Screenshot 1-25.)  If you have the Pictures window open, you may want to let it stick around a little longer.

 

Mac software Look4Faces

Screenshot 1-25

Mac software Look4Faces

Screenshot 1-26

 

Now, you should see another separate window with a large black screen.  (See Screenshot 1-26.)  If you click on the green play button video will play.  Now, if you just select one of the frame shots under the Pictures window, Look4Faces will locate the exact frame over the video player and set the play head accordingly.  (See Screenshot 1-28.)

 

 

Mac software Look4Faces

Screenshot 1-28

 

As you see the video player window, there are five video control buttons.  (See Screenshot 1-29.)  Clicking on the one to the very left will let you fast-rewind video.  There are two smaller control buttons around the play button.  These control buttons let you rewind or forward video by one frame at a time.

 

Mac software Look4Faces

Screenshot 1-29

Mac software Look4Faces

Screenshot 1-30

 

By this time, you should notice that there is a small tiny, red symbol with a transparent left-looking arrow right under the video control buttons.  This symbol indicates that there's no export folder defined.  That is, in order to take movie screenshots, you must first select a folder to which Look4Faces can send files.  In order to select an export folder, click on the Select button at the bottom or choose Select Export Folder under Player.  (See Screenshot 1-30.)  Then you will be prompted to select a folder or a volume.  The path that you select here refers to the security-scoped bookmark.  When you select a destination path and then quit the application, Look4Faces will remember it when you restart the application as long as that path exists.  Otherwise, you will see the same red symbol again.

 

Mac software Look4Faces

Screenshot 1-31

Mac software Look4Faces

Screenshot 1-32

 

Before clicking on the Screenshot button, let's first select an export format.  You can do so in Preferences.  Or explore Export Format under File.  (See Screenshot 1-31.)  You can aslo set a compression rate by exploring Compression under File.  This submenu gives you only several choices.  (See Screenshot 1-32.)  If you choose Other..., you will be prompted to enter a compression rate between 1 and 100.  (See Screenshot 1-33.)  Finally, notice that you can find out your export format selection and compression rate right below the path control.  (See Screenshot 1-34.)

 

Mac software Look4Faces

Screenshot 1-33

Mac software Look4Faces

Screenshot 1-34

 

There is nothing difficult about making a screenshot at the current play head position.  Simply, click on the green Screenshot button.  You can also choose Take Screenshot under Player.  (See Screenshot 1-35.)  If you do, Look4Faces will show a status messsage for 4 seconds at the bottom-right corner of the Player window.  (See Screenshot 1-36.)  Each screenshot will be named after the current play head position.  If Look4Faces finds an existing file inside your export folder, it will append a number to the timecode to avoid overwriting that existing file.

 

Mac software Look4Faces

Screenshot 1-35

Mac software Look4Faces

Screenshot 1-36

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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