Multi-language audio in Dolby E. A description of how to encode multiple COPYRIGHT 2011 AXON DIGITAL DESIGN B.V. ALL RIGHTS RESERVED

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1 Multi-language audio in Dolby E GEP00 - HEP00 description of how to encode multiple Gb/s, HD, SDin embedded domain Dolby E tothem PCM languages Dolby-E format and embed decoder with into a single SDIaudio videoshuffler stream product application note Quad speed Upgradable to Gb/s Embedded Metadata S00 COPYRIGHT 0 XON DIGITL DESIGN.V. LL RIGHTS RESERVED NO PRT OF THIS DOCUMENT MY E REPRODUCED IN NY FORM WITHOUT THE PERMISSION OF XON DIGITL DESIGN.V.

2 EMEDDED UDIO UDIO MULTI-LNGUGE IN DOLY-E Introduction The use of Dolby-E encoding gives broadcasters and facility operators the ability to embed up to 6 audio channels into a single SDI video: Dolby-E streams in each of the audio groups with each stream having a maximum capacity of 8 mono audio channels. n example of the utilisation of this is where a broadcaster is producing a transmission feed mixed in 5. surround sound for reception in multiple territories, with each territory requiring their own local language. y encoding each surround and associated stereo mix in Dolby-E it is possible to include 8 languages in the SDI video which could then be passed through the playout path in the conventional manner. The Dolby E signal is not intended for distribution usage; it is decoded back to baseband audio just prior to the final digital transmission, and then reencoded into the final audio format as required by the intended distribution platform. Possible Dolby E program configurations could include: full range surround audio channels a band limited low frequency effects channel surround sound channels mono channels which could be used for audio description surround sound channels stereo channel which might be used for an alternative two-track version of the surround sound mix lignment of Dolby-E in Video Systems Dolby E streams include audio and metadata encoded into blocks of SMPTE 7M data, streamed on a discrete channel or embedded into SDI. s the Dolby E bit-stream is normally carried along with video these data blocks are output at a rate associated with a chosen video frame rate. Possible video frame rates are: 9.97 fps (NTSC); 5 fps (PL);.98,, 0 fps. The Dolby E specification also ensures that the audio frames are synchronous with video frames, enabling programmes to be switched and edited without having to decode and recode the audio. To allow error-free cuts only editing and video source switching in routers, mixers etc., a short period in each frame has silent samples around the point in the stream at which the edit or video switch is intended to occur, this period is known as the guard-band. The point of where the guard band ends and the SMPTE 7M Dolby E data burst starts is often called the Line Position. This relates to a specific video line to which the start of the Dolby E data is aligned. The ideal location of a Dolby-E frame is so that it starts after the video switching point and it finishes before the end of the video frame. The location of the Line Position to place the Dolby-E frame in the centre of the video frame is 70µS after the start of the video frame, this can be safely varied by 680µS. The actual line that this timing is related to depends on the video standard being utilised: 65i5 (SD PL) Line 70p50 (HD PL) Line 8 080i50 (HD PL) Line 55i9.97 (SD NTSC) Line 70p59.9 (HD NTSC) Line 080i59.9 (HD NTSC) Line 6 Synapse Card Reference Selection and Video Timing The importance of correct system timing is critical in building a system that will successfully encode and embed Dolby-E within a SDI stream. The Dolby-E frames need to be generated at the same frame rate as the video they are to be embedded into and these frames need to be correctly aligned with the video frames. Synapse cards provide the necessary functionality and selection choices to allow this to reliably occur. The diagram below (page 6) shows a possible scenario where 8 separate surround sound sources are encoded and embedded into a single HD-SDI signal. In addition to embedding the Dolby streams the HE990 card also has a delay function which is used to synchronise the video with the Dolby encoded audio following the -frame processing delay. The diagram shows the DE08 Dolby encoder cards connected to the embedder via an external ES connection and via the Synapse dd-on us which require the card encoder cards to be located immediately to right of the embedder in the same frame, this has the advantage that all of the connections are taken care of without external cables and also the various clocks on the Dolby encoder are locked to the video source via the page

3 EMEDDED UDIO UDIO MULTI-LNGUGE IN DOLY-E MasterCard signal also carried on the bus. Up to four DE08 cards can be connected in this manner each inserting the Dolby-E stream onto tracks / of successive SDI audio groups, these can then be repositioned onto the desired tracks in the output SDI stream using the audio shuffler functionality within the HE990 embedder card. If locating the Dolby-E encoder card next to the embedder in not practicable, or there is a requirement for more than four Dolby-E streams, cards can be connected using external balanced or unbalanced ES cables, in which case the card should be locked to an external video reference signal synchronous with the video into which the Dolby-E encoded audio was to be embedded. The DE08 Dolby-E encoder uses the reference signals distributed throughout the Synapse frame to determine where a Dolby frame should start and stop, therefore it is critical that the video into which the Dolby-E frames are to be embedded is referenced to the same source as the Synapse frame. The video should be timed so that it is synchronous with the reference signal at the input of the HE880 embedder, this can be achieved by adjusting the source s timing or changing the amount of delay introduced into the video signal by the HE990 embedder module. It should be noted that none of the cards in this system provide frame synchroniser functionality, if the source to the system is expected to change or its timing cannot be fixed and therefore changing its timing relationship with the Dolby-E encoder, xon would recommend placing a synchroniser (such as the HFS00) in the video path before the de-embedder card. y adopting this methodology Dolby-E frames produced by the DE08 card will be correctly inserted within the video frame on the embedder card. If further adjustment of the Dolby-E frame timing is found to be required it can be achieved using the Guard and Delay control on the DE08 card, this can add an additional 65-lines of delay to the Dolby-E frames. Card Settings The following tables give examples of the configuration options required to successfully decode the Dolby-E stream, insert a V/O into it, encode the mix as a Dolby-E stream and embed the stream into the original SDI signal. Please note that the cards have considerably more settings than shown here and these should be set to match the user s individual requirements. DE08 Settings (Connection via Synapse dd-on us). Lock Mode = MasterCard, references the encoding processes to the HE880 MasterCard s clocks. The framing of Dolby-E packets is related to the Ref video timing.. Lock Mode = Reference, locks the cards time and Dolby-E packet phasing to external reference Ref. Program Config should be configured to suit the user s requirements (shown here for 5. surround sound). The letter refers to the Metadata configuration chosen (see item ).. ypass Delay = 0mS, if the Dolby-E encoder is bypassed this configuration delays the audio by the same amount as the encoding process to ensure continued lip-sync. 5. Selects the Metadata set to be edited, Sets are used by the Program Config (see item ). 6. udio Coding Mode = / and LFE Enable =, configures the encoding format in the metadata used by subsequent decoders, this example it configured for 5.. page

4 EMEDDED UDIO UDIO MULTI-LNGUGE IN DOLY-E HE990 Settings. Input Select = SDI- & Switch ack = Off selects SDI as the source of video to have the Dolby-E streams added to and also prevents the module switching to the other source should the input fail. Lock Mode = Ref locks the card to an external source of video reference, essential if the Dolby-E encoding and insertion timing is to be correct. Frame Delay = Frame, adds delay to the video signal to compensation for the Dolby-E processing time.. Non PCM ypass = On, this bypasses audio processing for signals which are not PCM audio, such as a Dolby-E encoded data stream.. Local xx/x = Transparent, ensures Dolby-E signals will not be processed, this is simply a fail-safe, (above) accomplishes the same thing.. dd On = Selected, the configuration shown will route the audio from the dd-on bus (originating on the DE08 card) to the SDI Group, channels and, inserting Dolby-E encoded audio onto tracks and in the SDI stream. Note the channels need to be selected individually.. Local = Selected, routes the Dolby-E stream from ES- to channels and of audio group (SDI tracks 9 and 0). page

5 EMEDDED UDIO UDIO MULTI-LNGUGE IN DOLY-E Dolby-E line position alignment process Connect cards as shown below ensuring the Synapse frames have at least one external reference connected and that they are all originate from the same generator. Determine if the timing of the input video may change if yes install frame synchroniser prior to embedder. Set the HE990 Lock-Mode to the reference bus which has an external reference connected i.e. Lock Mode = Ref. Ensure the Ref-Input of the DE08 Dolby-E encoders is set to the same reference source. Set the delay of the HE990 to Frame to compensate for the processing delay through the Dolby-E encoders. djust the timing of the video source to the HE990 embedder to be synchronous with the frame s internal reference at the output of the card (this can be easily ascertained using the Measurement option on a Tektronix 70 WFM or similar). Timing adjustments can be made at the source of the video prior to the embedder or using the delay functionality of the embedder card. This will align the video with the Dolby-e data packets being generated by the DE08 cards. If the DE08 is connected to the embedder by the Synapse us select Lock Mode = MasterCard, otherwise select Reference. Check the positioning of the Dolby-E data within the video output from the HE990, either change the card s delay so that the Line Position is correct or use the Guard-and Shift function on the DE08 card to delay the Dolby frames if required. page 5

6 page 6 Language F SL/SR Language F C/LFE Language F - L/R Language E SL/SR Language E C/LFE Language E - L/R DOLY E OUTPUT Language - L/R Language SL/SR ES 7/8 ES 5/6 INTERNL SYNPSE US udio in/outputs Y-PSS DRS CHNNEL / [UX] UX OUT Language SL/SR Language C/LFE ES 7/8 ES 5/6 ES / ES / METDT GIN CHNNEL SWP MIN OUTPUT UX OUT ES / METDT CHNNEL / [UX] Language C/LFE Language - L/R INTERNL SYNPSE US Y-PSS DRS DOLY E OUTPUT ES 7/8 ES 5/6 ES / ES / DE08 udio in/outputs GIN CHNNEL SWP METDT ES / MIN OUTPUT G/HE990 ONLY INPUT 8 INPUT 7 INPUT 6 INPUT 5 INPUT INPUT INPUT INPUT METDT Gb/s, HD, SD IN Gb/s, HD, SD IN METDT DE08 Up to ES streams each carrying a Dolby-E encoded language Input Program Video ES 7/8 ES 5/6 ES / ES / System Schematic MULTI-LNGUGE UDIO IN DOLY-E DE08 DE08 Eq Eq DJUSTLE OFFSET 0-500ms GIN CHNNEL SWP GIN CHNNEL SWP EM RCK LER CHNNEL / [UX] MIN OUTPUT CHNNEL / [UX] MIN OUTPUT EM D UX OUT DOLY E OUTPUT UX OUT DOLY E OUTPUT /O Gb/s, HD, SD OUT Gb/s, HD, SD OUT dditional DE08 modules can be connected on the dd-on bus Y-PSS DRS Y-PSS DRS INTERNL SYNPSE US EM C UDIO INPUTS FROM SYNPSE US INTERNL SYNPSE US udio in/outputs INTERNL SYNPSE US Ch Ch Ch EM = SINGLE CHNNEL = DUL CHNNEL Ch Ch Ch Ch Ch PRESET SED X6 CHNNEL (X6 FOR G/HE900) INPUT MULTIPLEXER FOR EVERY EMEDDER GROUP S00 INSERTION DJUSTLE OFFSET 0-500ms udio in/outputs REFERENCE INPUTS UTO MUX x OR x UTO PHSER UTO PHSER GE990 GE900 HE990 HE900 Delay = Frame to compensate for Dolby-E processing latancy Up to ddon buses each carrying a Dolby-E encoded language Output Video with up to 8 Dolby-E encoded audio languages