avplayback(1)

NAME
     avplayback - playback uncompressed video and audio in synchronization

SYNOPSIS
     avplayback -[a# b# d# h r# t%s v vlan_cmd_file A B D V] <filename>

PARAMETERS
     -a <audio format>
          specifies the file format of the audio data:
             1 =  no audio
             2 =  QuickTime
             3 =  AIFC
          If audio output is not disabled with -a1 an embedded audio track
          will be played if it exists.  If an embedded track does not exist
          then a file with the suffix .aifc will be opened for playback.

     -b <buffer size>
          allows you to specify the maximum number of buffer elements to be
          allocated. By default, 4 buffers are used, but the value can be
          adjusted for I/O load balancing. The maximum number of buffers which
          can be allocated is limited by the amount of available physical
          memory in the system.

     -d <video device number>
          specifies the video device to be used (as reported by vlinfo).  This
          need not be specified unless you have more than one video device in
          your system; it defaults to 0, i.e. the first device found.


     -h   prints a usage message giving a summary of available flags.

     -r <scatter gather>
          specifies the number of images to simultaneously read from disk
          using readv(2)

     -t </dev/ttyd#>
          specify the tty device port for serial RS422 V-LAN control

     -v   instructs the program to parse the specified file for V-LAN commands
          and to issue them immediately.


     -A   abort if any image is dropped (when a VL sequence lost event is
          generated).


     -B   calculates the video disk I/O performance and prints the results
          after the last image is output.

     -V   enables verbose mode and prints the values of parameters used to
          setup the hardware for audio and video transfers.


     <filename>   specifies the name of the file to read.  If the -a2 option
                  is chosen audio data will be in the separate file
                  filename.aifc.  If the -a3 option is chosen audio data will
                  be embedded in the QuickTime file filename.

DESCRIPTION
     The utility avplayback uses the Digital Media libraries to output a
     sequence of video images and audio samples from various Silicon Graphics
     digital media devices.  As of this release audio data originally captured
     with avcapture in a separate AIFC file played in sync with the video
     using the -a3 option.  If the audio and video hardware are locked to a
     common external reference signal the audio and video data are guaranteed
     to remain synchronized.  If either device drops data synchronization will
     be recalibrated.  Visual or audio artifacts may be noticed at this time.

     avplayback is best suited to playback large volumes of audio and video
     data in realtime.  This is possible if a striped logical volume disk
     array of sufficient size and configuration is used with the XFS file
     system.  Before copying data to disk from an external source test the
     performance of the array using the tool diskperf.  It may be necessary to
     reconfigure the array with diskalign before realtime playback can be
     achieved.

     See /usr/share/src/dmedia/movie for details on how to create and edit
     QuickTime files using the SGI movie library.

     All of the video control parameters including output timing and data
     format are automatically set by the tool.  If audio output is enabled
     default audio device is used.  The audio control parameters can be
     adjusted with apanel.

     The -v option specifies a text file containing V-LAN edit commands.
     Robust error checking is not performed, therefore, unpredictable behavior
     should be expected if invalid V-LAN commands are issued or if the
     commands are issued in the wrong order.  Permissions and ownership of the
     command file must be properly set.  If V-LAN control is chosen and the CO
     (Coincidence On) and SC (Set Coincidence) commands are issued the GPI
     output of the video device must be connected to the V-LAN receiver in
     order to accurately initiate the data transfer.  This option should be
     used in conjunction with the -t flag.  A special cable must be
     constructed for the trigger output.  See Appendix A of the DIVO XIO Board
     Owner's Guide for details.

SEE ALSO
     avcapture(1), diskalign(1), diskperf(1), memtovid(1), orion(1),
     vidtomen(1)