A unique solution to lip-sync problems

AVDELAY 3G is a unique way of dealing with large lip-sync problems on incoming 3Gb/s, HD or SD signals containing up to four groups of embedded audio that have a big timing difference between the video and audio paths.

Broadcast engineers are increasingly looking for innovative ways to get signals from one side of the world to the other, but sending the video and audio signals back to base by different methods (satellite, Skype, ISDN and so on) can result in multiple seconds timing difference between the vision and audio commentary.

That’s where AVDELAY 3G comes in. You can use it to match the video and audio: with independently adjustable video and audio delays, it provides up to ten seconds of video delay along with ten seconds of audio delay.

No longer do you need to buy multiple boards to provide this functionality. AVDELAY 3G is a unique one-board solution that replaces separate audio and video delays, making it both more cost-effective and easier to control.

Why do you need an AVDELAY 3G?

Lip-sync is a common problem. In the past there was a timing difference of maybe one or two video frames. But we’re starting to see situations where the timing relationship is much greater – sometimes seconds difference between the video and audio. Why?

This increase in timing difference has been caused by broadcasters looking for innovative ways to get signals from one part of the world to another without having to use expensive dedicated satellite links. They will often take the host broadcaster’s international video feed and then send the audio commentary back to base using an inexpensive method such as the Internet.

The video path going via satellite links could be delayed by one or two seconds, while the delay for the audio commentary could be variable – almost instant in the case of something like Skype or significantly longer with ISDN. When the signals arrive back at base there could therefore be several seconds timing difference between the audio commentary and vision – quite critical for a sporting event, for example, where the commentary needs to coincide with the action.

Although the video and audio come in separately, they are often packaged up as video with embedded audio and sent off to the production area. And this is when AVDELAY 3G might sit on a central router as a resource, with its ability to deal with four groups of embedded audio. When the broadcast engineer has signals coming in that need the A/V adjustment, he simply routes these signals through the AVDELAY 3G.

How much delay do you get?

Having both audio and video delay means that AVDELAY 3G can cope with the lip-sync being out in either direction – for example, if the audio is earlier than the video, then AVDELAY 3G can be used to delay the audio to let the video catch up.

With different standards having different amounts of data, the maximum video delay will change depending on the video standard. The audio delay is not affected by the video standard. The minimum video and audio processing delay is one frame.

How do you adjust the delay?

To adjust the video and audio delay, you need to view the source on a monitor and match the video and audio by eye.

AVDELAY 3G has been designed with maximum flexibility when it comes to setting or bypassing the various delays. The video delay is adjustable in seconds and frames. The audio delay is adjustable in seconds, video frames and milliseconds. The video and audio will jump instantly to the new delay setting, allowing you to rapidly correct lip-sync errors.

Dealing with the embedded audio is particularly flexible. There are four separate audio delay processors and each delay block can its own delay timing – providing you with a total of four different audio delays at the same time on AVDELAY 3G. Ideal if you have a number of audio tracks coming in via different mechanisms, such as Skype and ISDN. The audio is de-embedded, with each mono audio channel then individually assigned to any one of the four audio delay blocks – or set to bypass the delay completely. So you can assign all 16 mono channels to a single delay block, or use all four!

Three default buttons allow you to set all the video and audio delays to 0, 5 or 10 seconds, giving you a useful starting point for making your adjustments.

Looking after your Dolby E

AVDELAY 3G provides sophisticated handling of Dolby E audio, automatically aligning the guardband with the outgoing video.

Dolby E can be assigned to the four audio delay blocks in the same way as other audio, and the delay applied to the Dolby E will be the delay setting rounded to the nearest time that gives the correct guardband alignment. The Dolby E channels are maintained as pairs and both channels of a Dolby E signal will be assigned to the same delay.

Flag up faulty signals

AVDELAY 3G includes signal status reporting with 21 video and audio alarms available, which makes it useful for flagging up faulty signals.

The status indications include input video missing, audio groups missing, audio silence and Dolby E presence. Video missing and audio groups missing will assert an alarm immediately, while the silence alarms can be delayed by up to 128 seconds before an alarm is asserted to prevent false alarming during quiet audio periods. One GPI output is reserved for alarm indication (and can be assigned any number of the alarm conditions), while warnings of any problems can be provided via Statesman alarms or SNMP traps.

Integrated fibre input or output connectivity - on the board

It is easy to give AVDELAY 3G integrated fibre input/output connectivity – while still only using a single frame slot. Simply request either the FIP fibre input option or FOP fibre output option to be fitted to the motherboard by Crystal Vision.

Designed for SMPTE 297-2006 short-haul applications the FIP is used to receive an optical input and the FOP used to transmit an optical output using a Class I laser. If a FIP is fitted, you can select your video input source to be taken either from the input BNC or the optical input. If a FOP is fitted, you'll get a copy of the output on fibre.

Having the fibre integral to the board reduces the need to use up additional rack space for separate fibre optic transmitters and receivers – and also saves you money.

AVDELAY 3G can also support CWDM lasers if required.

Save rack space

AVDELAY 3G is a space-saving 100mm x 266mm module which fits in the standard Crystal Vision frames - available in 4U, 2U, 1U and desk top box sizes - and with up to 12 boards fitting in 2U. The one 3Gb/s, HD or SD input and two outputs are accessed by using the RM62 frame rear module.

Choose your control

The flexible control options include board edge switches, an active front panel on the frame, a remote control panel, GPIs, SNMP and the Statesman PC software.

Up to 16 user-defined presets can be stored and recalled – ideal for saving you time in those situations where you know you are going to get a certain delay between the signals. You can store that delay setting in a preset and then quickly recall it as required.