Optional Content Delay

Using Optional Content Delay

If your requirements include recording content for playback and distribution to different sites in different time zones, you may want to order iPort HD  with the Content Delay option. Its features include:

• NTP synchronization for the content delay on absolute time.

• Built-in SSD with dynamic storage space allocation, configurable per codec.

• Delay of GPIO and user data channels synchronized with audio.

Content Delay is not a field-installable option. The factory must install it at the time you place your order.

To verify that your iPort HD does indeed contain Content Delay, go to the License Management page. Feature licensing status is shown at the top of this page. Make sure that Content Delay is marked Active (not Inactive as shown in this example).

Content Delay Configuration

Setting the Storage Space Management Options

The total amount of content that you can store on the iPort HD is based on several factors.  

• The size of the installed storage drive

• The number of codecs using the Content Delay

• The bitrate of the codecs using the Content Dealy

From the Codec Configuration page, click the Global Options button at the top right. Set the following two parameters (bottom two sections of the page):

Maximum expected bitrate per stream (kbps)

The maximum expected bitrate per stream setting is used to calculate the total program storage time of the Content Delay feature based on the installed physical storage space. It shows maximum storage space, current free storage space, and currently configured storage time from all codecs.

In this example, based on a stream rate of 192 kbps, there is a total storage time of 1044 hours, 30 minutes.  Only 10 hours, 7 minutes of storage are currently configured.

Delay relative to packet arrival time, ignore sender timestamps

This option determines whether the content will be delayed by the set time relative to its creation time at the sender (option unchecked) or relative to the receiver's arrival time (option checked).

Individual Codec Storage Options

The configuration is done individually from each Codec's Options page.

1. Click the Options button for the Codec you want to configure.

2. Scroll to the bottom of the page.

3. Check the box to Enable content delay: then click Apply.

4. Using 24-hour time, enter the Storage duration.

5. Enter the Playback offset.

6. Click Apply.

A good analogy is to think of Content Delay as a pipe.  The Duration to Store determines the pipe's length, while the Playback offset controls the point at which you tap into the pipe.

This scheme allows you to instantly switch to any point of the stored program, back and forth, as long as the fragment is still in the pipe.

Note that 'playback offset' is the actual delay time as measured from the instant of content creation. All calculations under the hood are based on UTC, regardless of the local time-zone setting.

Note that the resolution for playback offset goes to milliseconds, allowing you to correct delays in digital transmission links.

The display also tells you the total amount of storage space, how much is still available, and the total time available for this particular codec. Each codec instance is limited to 24 hours. Within that range, free storage space is available to any codec.

SSD Housekeeping

If you want to check up on the Solid State Drive's health, make repairs, or format the drive, go to the bottom of the Logging page and click on the Storage Maintenance button.