In a “live to tape” video workflow, you shoot and switch a multi-camera production live, and record the switcher program output (known as a “line cut”).  After the shoot, you can edit the line cut recording before distribution.  If you also record each of the individual cameras (known as “ISOs”, short for “isolated cameras”), you can enhance the line cut by inserting select clips from cameras different than the one the director chose at the time of live program shooting.  This ensures that the end result is always of high quality, though most production effort was done during the shoot.  Live to tape saves you time compared with editing the entire program from just the ISO recordings after shooting.

Today, of course, “live to tape” recording does not use “tape”, but instead uses more modern storage methods.  To provide the most flexible and cost-effective workflow, you encode the live video streams and send the compressed flows to the cloud, where editors finish the program on cloud edit workstations.  Content is thus received in the cloud faster than if the show was recorded on premises, edited on premises, and only then sent to the cloud afterwards as a file transfer.  You only pay for cloud edit workstations used during the time of the editing process, instead of having dedicated on-premises workstations which are idle most of the time.  And your editors can connect to cloud editing workstations from any location with an Internet connection.

For example, your workflow may require five ISO cameras and the line cut, with a resolution of 3840×2160 with 4:2:2 10-bit sampling at 29.97 frames per second.  ProRes 422 HQ is the desired file format for your video editing application.  The data rate for ProRes at this resolution and frame rate for a single channel of video is 884 Mbps.  For the six simultaneous recordings, the total data rate is 5.3 Gbps.  While that data rate is possible to establish between on-premises and the cloud, the high cost of that connection might be unacceptable.

To reduce the required network data rate to the cloud, a codec with inter frame prediction can be used, since the “live to tape” workflow does not have an ultra-low latency requirement.  For example, you could use an AWS Elemental Live on-premises encoder fed with uncompressed SDI or SMPTE ST 2110 from the studio equipment.  For HEVC encoding at 25 Mbps, the total required data rate is only 150 Mbps to transport all the six live video streams with excellent quality.  The streams can reliably be sent to the cloud using the Secure Reliable Transport (SRT) protocol.  SRT compensates for packet loss, jitter and bandwidth fluctuations over Internet paths.  And SRT uses 128-bit or 256-bit AES encryption to secure the video as it is transported.  AWS Elemental MediaConnect receives the SRT stream on the cloud and forwards the video to the recording application.

Grass Valley AMPP provides efficient and flexible media production workflows for creating, managing, and distributing live content via multiple apps. HEVC video streams from the “live to tape” production are captured on the cloud by the Grass Valley AMPP Elastic Recorder app running on an Amazon EC2 G5 instance.  The Elastic Recorder can record streams to storage in a wide range of formats. Recorded timecode can be from the incoming source, at a fixed start time, or as Time of Day (with a UTC offset) locked to an NTP source.  Elastic Recorder is fully integrated with AMPP Scheduler, or it can work standalone with scheduled start time or crash record capabilities.

 

 

 

The HEVC 4K live stream is recorded to ProRes 422 HQ using the AMPP Elastic Recorder connected to Amazon FSx for Windows File Server (FSx for Windows), a service that provides fully managed file storage built on Windows Server, with selectable throughput capacity from 32 MB/s up to 12 GB/s.  FSx for Windows can be deployed with single-AZ or multi-AZ file systems.  For enhanced resiliency, multi-AZ file systems are composed of a high-availability cluster of Windows file servers spread across two AZs, leveraging Windows Server Failover Clustering (WSFC) technology and a set of storage volumes on each of the two AZs. Data is replicated synchronously within each individual AZ and between the two AZs. 

Configuration Details

Let’s examine the configuration details of an example “live to tape” workflow.  First, the AWS Elemental Live encoder is used at the studio to convert content into high quality HEVC encoded streams. The encoding profile used is 3840×2160 resolution, with 4:2:2 10-bit sampling at 29.97 frame rate and 25Mbps. 

 

 

The encoded high quality video stream is sent using SRT to AWS Elemental MediaConnect flow on the cloud, and then sent via a MediaConnect output to GV AMPP Elastic Recorder for ingest and recording.

 

 

GV AMPP is configured to receive the SRT stream from the MediaConnect output. An Elastic Recorder is deployed for each stream to record the media in ProRes 422HQ on a locally attached FSx for Windows file system. This screenshot shows the Z: drive as a network drive attached to the AMPP EC2 instance. 

 

 

Now that the files are being recorded to FSx for Windows, editors can begin to edit using the files via NICE DCV virtual desktop interfaces to Adobe Premiere editing systems running on Amazon EC2 instances.  For more information on edit in the cloud, see the Edit in the Cloud Solution.  There also is more information on scaling edit in the cloud workflows on Amazon FSx for Windows.  

Conclusion

While “live to tape” doesn’t really mean “to tape” anymore, a more modern workflow is “live to cloud”.  This ensures that your content gets into the cloud faster where it can be edited by staff located anywhere in the world with an Internet connection, and then can be processed using AI for metadata enhancement, shared with content partners on the cloud, and archived in a secure and affordable fashion on the cloud when the production is complete.  And you only pay for the virtual infrastructure while it is in use.

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