AV-Sync – Manual media file preparation

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1. Manual method

To manually prepare you media files, the use of video editing software is required. Please refer to the software’s user manual to determine how to execute the following steps.

1.1. Basic

The following steps are required for normal usage of AV-Sync.

  1. Save the original video
    Save the original video that is to played to an easy to access location on your hard drive.
  2. De-mux (split) the audio track from the video, and save it in MP3 format (64 kbps, mono, 48 kHz, -1dB peak level)
    • Split the audio that is to be played by the Podcatcher from the original video
      • Download Avidemux (or any other software you would like to use).
      • Open the video file.
      • Choose “Save audio” from the “Audio” menu.
      • Browse to a location on your hard drive to save the audio file. Choose a file name like “MyAVSyncClip.m4a”.
    • Prepare the MP3 file for playback on the Podcatcher
      • Download Audacity (or any other software you would like to use).
      • Open the audio file you have saved in the previous step.
      • Make the sure that the “Project Rate” as visible in the lower left of the screen is set to 48000 Hz.
      • If required, amplify the track to an appropriate volume level. We recommend -1dB peak level.
        • Choose “All” from the “Select” menu.
        • Choose “Amplify” from the “Effect” menu.
        • Enter the new peak amplitude: -1
        • Click “OK”.
      • Optionally, extend the audio track for loop correction. However preferably use the slider in the tour editor to configure this: see “Fine tuning” in the AV-Sync manual.
        • Scroll right and click on the end of the track, where a yellow line will appear.
        • Choose “Silence..” from the “Generate” menu.
        • Adjust the duration of the silence to the measured loop time (the time the media player requires to restart the video) and choose “OK”.
      • Export the file in MP3 format, without ID3 tags.
        • Choose “Export” -> “Export as MP3” from the “File” menu.
        • Select “Constant” at the format options.
        • Adjust the quality to one of the recommended formats:
          • 64 kbps, Mono
          • 128 kbps, Stereo
        • Click “Save”.
        • Browse to a location on your hard drive to save the audio file. Choose a file name like “MyAVSyncClip.mp3”.
        • At the window “Edit Metadata Tags” choose “Clear” to remove all metadata.
        • Click “OK”.
    • The MP3 file is now ready to be uploaded in the TourEditor.
  3. Download the AV-Sync track
    • The regular AV-Sync track can be downloaded as a zipped WAV-file from this link to a known location on your computer.
    • Unzip the file: click right mouse button, choose “Extract all..”
    • When using the AV-sync in flexible mode, multiple, different AV-Sync tracks are required. You can ask our helpdesk for more information.
  4. Mux (add) the AV-Sync track to the original video
    • The AV-Sync track is provided in WAV format, which provides the best signal quality to the AV-Sync box. The audio content of the track must not be altered in any way for the system to function. We recommend not converting the AV-Sync track to a different format if not required. However for many video formats, the MP3 or AAC format is more standard to use as audio track. Conversion to these formats is no problem, as long as the bitrate is set high enough to prevent signal degradation. As a guideline, use 128 kbps or higher for AAC, or 192 kbps for MP3. Conversion can be done using editing software of your choice. This section provides an example using Audacity and Avidemux.
    • Optionally convert the AV-Sync track to MP3 format, for muxing with video in MP4 format.
      • Download Audacity (or any other software you would like to use).
      • Open the AV-Sync track.
      • Export the file in MP3 format.
        1. Choose “Export” -> “Export as MP3” from the “File” menu.
        2. Select “Constant” at the format options.
        3. Adjust the quality to 192 kbps or higher.
        4. Select “Mono” as channel mode.
        5. Click “Save”.
        6. Browse to a location on your hard drive to save the audio file. Choose a file name like “AVSyncTrack.mp3”.
        7. Click “OK”.
    • Add the AV-Sync track to the video. Make sure that both video and audio start at offset 0. Also make sure that the AV-Sync track is cut short when the video ends. The full original AV-Sync track has a fixed length of 2 hours.
      • Download Avidemux (or any other software you would like to use).
      • Open the video file.
      • Choose “Select track” from the “Audio” menu.
      • Select “Track 0 from.. “, choose option “Add audio track” when it appears.
      • Browse to the location of the AV-Sync track on your hard drive and open it.
      • Click “OK”.
      • Select “MP4 Muxer” as Output format.
        • Note: Using “MP4v2 Muxer” may cause problems when using Brightsign media players.
      • Click “Save” from the “File” menu.
      • Save the new video to an easy to access location on your computer using a new name. This video file is to be used for playback on the media player connected to the AV-Sync box.

1.2. Advanced

This section describes optional steps for more advanced AV-Sync setups.

  1. Play audio on speakers (room audio), in sync with audio played on Podcatchers.
    • This step is required if audio must be played not only on the Podcatchers, but also directly from the media player. This is the case if the use of audio guides is optional, for instance to allow listening in a different language.
    • You can skip this step if all audio is to be played through the Podcatcher.
    • Normally, for use of AV-Sync the audio track played by the media player is replaced by the AV-Sync track. The AV-Sync track requires only a single channel. You can use the other channel to play room audio. For this, the left channel of the original audio of the video must be added as the left channel to the AV-Sync track, making it stereo. This makes original audio available on the white RCA connector of the audio cable from the media player, which is normally unconnected. The AV-Sync track must remain on the right (as in, opposite of left) channel of the track, which should be output on the red RCA connector which is connected to the AV-Sync box.
    • Download Audacity (or any other software you would like to use).
    • Open the AV-Sync track.
    • Choose “Import” -> “Audio” from the “File” menu
    • Browse to the audio file that you have split from the original video (for example: “MyAVSyncClip.m4a”). Two audio files are now opened, both having two channels (stereo). These need to be merged to a single stereo audio file.
    • Click on the label “AV Sync Track” to open a menu. From it, choose, “Split Stereo Track”.
    • Click on the label of the audio file from the original video and do the same.
    • Remove the empty left channel of the AV Sync track by clicking the X mark.
    • Remove the right channel of the audio file from the video by clicking the X mark.
    • Click on the label “AV Sync Track” to open a menu. From it, choose, “Make Stereo Track”. The two remaining mono tracks now form a single stereo track.
    • Export the file in MP3 format.
      1. Choose “Export” -> “Export as MP3” from the “File” menu.
      2. Select “Constant” at the format options.
      3. Adjust the quality to 192 kbps or higher.
      4. Select “Stereo” as channel mode.
      5. Click “Save”.
      6. Browse to a location on your hard drive to save the audio file. Choose a file name like “AVSyncTrackWithRoomAudio.mp3”.
      7. Click “OK”.
    • Continue at the step “Add the AV-Sync track to the video” as described above.