Routing “Mono” Audio in a Multi-Channel Environment

Presenters : John Mailhot - Imagine Communications

Year : 2019

dlp_document_download : Routing "Mono" audio in an Multi - Channel stream Environment John Mailhot, CTO Networking & Infrastructure Imagine Communications Why is Audio always the Problem? • Audio is used in very different ways in different parts of the air chain • Playout, Master Control, and Distribution (usually) organize the audio into finished mixes (5.1, 2.0). • Production (usually) organizes the audio into groups of related sources – but it varies… • Both have exceptions and variations • IP did not create this headache The Audio Problem in IP • In IP systems, audio is organized into streams • Streams usually contain multiple channels • Multi - channel streams help manage complexity • IS - 04 lists the streams (senders) • IS - 05 switches the streams (receivers) • But what if you want to manipulate it? • Shuffle, substitution, or even wild - mapping? How? What Problem does IS - 08 Solve? • IS - 04 and IS - 05 treat audio streams as monolithic essences – mixes or tracks to be kept together in the network, and switched together to the receiver • Sometimes, operationally, there is a need to route the individual tracks more specifically – at the "mono" level • IS - 08 provides an open/public API for controllers to manipulate the individual tracks on receivers and senders, while retaining the general efficiency of keeping related tracks organized together into streams Why not just make every mono channel into a separate multicast audio stream? • Making each track its own stream is possible, except… • It creates a more complicated system overall because of the very large number of streams • Some receiving devices don’t have a lot of separate audio stream receivers, so (you cant use them) • Overall signal switching time can suffer because of the number of separate stream "joins" in every operation • What is Stream Routing? Its what 2110 -30 + IS -05 does by default • Routes logical groupings of content easily Audio Stream Routing Playout System A (SRCA) 2110 -20 video 2110 -30 audio (5.1 mix) 2110 -30 audio (2.0 mix) Playout System B (SRCB) 2110 -20 video 2110 -30 audio (5.1 mix) 2110 -30 audio (2.0 mix) MCR 1 In 1 In 2 Preset Program MCR 2 In 1 In 2 Preset Program • What is Stream Routing? Its what 2110 -30 + IS -05 does by default • Routes logical groupings of content easily • Break -away routing at the stream level Audio Stream Routing Playout System A (SRCA) 2110 -20 video 2110 -30 audio (5.1 mix) 2110 -30 audio (2.0 mix) Playout System B (SRCB) 2110 -20 video 2110 -30 audio (5.1 mix) 2110 -30 audio (2.0 mix) MCR 1 In 1 In 2 Preset Program MCR 2 In 1 In 2 Preset Program SRCB.vid  MCR2 -2.vid SRCA.a1  MCR2 -2.a1 SRCA.a2  MCR2 -2.a2 • What is Stream Routing? Its what 2110 -30 + IS -05 does by default • Routes logical groupings of content easily • Break -away routing at the stream level • But how do you integrate signals that are not consistent? Audio Stream Routing Playout System A (SRCA) 2110 -20 video 2110 -30 audio (5.1 mix) 2110 -30 audio (2.0 mix) Playout System B (SRCB) 2110 -20 video 2110 -30 audio (5.1 mix) 2110 -30 audio (2.0 mix) MCR 1 In 1 In 2 Preset Program MCR 2 In 1 In 2 Preset Program Sat Rx 7 2110 -20 video 2110 -30 audio ( chan 1..8) 2110 -30 audio ( chan 9..16) SDI GW What do I do with these? They are different for every show. And they are not organized like the others. • System can treat the internal audio channels as the routing destinations • Controller manages the device’s stream receivers using AMWA IS -05 • Controller manages the device’s audio mappings using AMWA IS -08 • User can have total control in a logical way through control system using both Audio Stream Routing + Track Routing Playout System A (SRCA) 2110 -20 video 2110 -30 audio (5.1 mix) 2110 -30 audio (2.0 mix) Playout System B (SRCB) 2110 -20 video 2110 -30 audio (5.1 mix) 2110 -30 audio (2.0 mix) Sat IRD7 2110 -20 video 2110 -30 audio ( chan 1..8) 2110 -30 audio ( chan 9..16) SDI GW (RX7) vid A 1 A 2 A 3 A 4 A 5 A 6 A 7 A 8 vid A 1 A 2 A 3 A 4 A 5 A 6 A 7 A 8 MCR transition processing vid A 1 A 2 A 3 A 4 A 5 A 6 A 7 A 8 Audio MAP Audio MAP Stream RX 1 Stream RX 2 Stream RX 3 Stream RX 4 SRCA.a1  MCR1 -1.a1 SRCA.a2  MCR1 -1.a2 Stream RX 1 Stream RX 2 Stream RX 3 Stream RX 4 Stream TX 1 Stream TX 2 Audio MAP IS -08 enabled Device • System can treat the internal audio channels as the routing destinations • Controller manages the device’s stream receivers using AMWA IS -05 • Controller manages the device’s audio mappings using AMWA IS -08 • User can have total control in a logical way through control system using both Audio Stream Routing + Track Routing Playout System A (SRCA) 2110 -20 video 2110 -30 audio (5.1 mix) 2110 -30 audio (2.0 mix) Playout System B (SRCB) 2110 -20 video 2110 -30 audio (5.1 mix) 2110 -30 audio (2.0 mix) IS -08 enabled Device Sat IRD7 2110 -20 video 2110 -30 audio ( chan 1..8) 2110 -30 audio ( chan 9..16) SDI GW (RX7) vid A 1 A 2 A 3 A 4 A 5 A 6 A 7 A 8 vid A 1 A 2 A 3 A 4 A 5 A 6 A 7 A 8 MCR transition processing vid A 1 A 2 A 3 A 4 A 5 A 6 A 7 A 8 Audio MAP Audio MAP Stream RX 1 Stream RX 2 Stream RX 3 Stream RX 4 Stream RX 1 Stream RX 2 Stream RX 3 Stream RX 4 Operator can "wild map" the audio RX7 A2.3  MCR1 -2 A.1 RX7 A2.4  MCR1 -2 A.2 RX7 A1.7  MCR1 -2 A.3 RX7 A1.8  MCR1 -2 A.4 RX7 A1.1  MCR1 -2 A.5 RX7 A1.2  MCR1 -2 A.6 Stream TX 1 Stream TX 2 Audio MAP IS -08 can also control the output sender mappings SRCA.a1  MCR1 -1.a1 SRCA.a2  MCR1 -1.a2 • Audio Track Routing requires the controller to manipulate downstream of the receivers (and upstream of the senders). • Today, this is different on every device, and some devices don’t support an API even though they internally have the capability to route • So, the controller needs to create a driver for every different device • Nobody likes writing drivers for every new device • IS -08 provides a common API that devices can implement, to enable this very necessary behaviour Did we really need IS - 08? What is the Status of AMWA IS - 08? • IS - 08 has been tested at a workshop, and a last - call for comments was issued • The comments in the last - call were addressed • The Specification has been approved by the AMWA Board and is a published AMWA Interface Specification, IS - 08 ALL AMWA Specifications are available for FREE at https://amwa -tv.github.io/nmos/ Questions? John Mailhot CTO, Networking & Infrastructure, Imagine Communications Director, Advanced Media Workflow Association Director, Video Services Forum Document Editor, SMPTE 2110 - core Document Editor, JT - NM TR - 1001 - 1