Satcom Resources Blog

Adtec’s HD422 Encoders can send Four CONCURRENT (same time) GIGE routes (IP destinations) of the transport stream with unique configuration and FEC (SMPTE 2022) setting per destination! These routes are concurrent with ASI operational and internal constant capture with the hard drive if the TS rate is lower than 40 Mbs (old PATA hard drive limitation).

Adtec HD422 can encode four (4) MPEG 1 Layer 2 {they even support phase alignment of the MPEG 1 Layer 2 audio allowing surround sound without external processors when using the Tandberg TT1290 IRD}. Encoding also supports two (2) Dolby AC3 and two (2) MPEG 1 Layer 2 or any combination up to two each. Example, Encode one (1) Dolby AC3 and encode three (3) MPEG 1 Layer 2 audios.

Adtec can passthrough Dolby AC3/5.1/E, LPCM and Linear Acoustic E2. Passthrough support is via SDI and or AES. We can passthrough up to two (2) compressed Dolby (AC3/5.1/E) or Linear Acoustic E2 or two (2) SMPTE 302M (LPCM) audio streams. Dolby E, E2 and LPCM each take 2.308 Mbs.

Throughput for the 2.308 data rate:
Dolby E supports 4×2 or 5.1+2 (8 channels)
LPCM supports stereo audio (2 channels)
Linear Acoustic Stream Stacker E2 supports two (2) sets 4×2 or 5.1+2 or a total of sixteen (16) channels. E2 is equivalent to two (2) Dolby E boxes.
Base model NTT 9100 can pass one SMPTE 302M (nomenclature they use for Dolby E) and encode 2 MPEG 1 Layer 2. By adding NTTs additional audio board, they can pass two (2) SMPTE302M and even claim to pass four (4) with a very unique method with no audio encode capabilities with either two (2) or four (4) Dolby E passthrough. NTT is limited to TWO PIDs total when in passthrough mode. They claim they can passthrough four (4) Dolby E by combining two Dolby E payloads per AES3. This requires external audio processing to mix two Dolby E payloads onto a 96 Khz AES3 interface and requires sharing a single PID for two (2) Dolby E payloads. NTTs four (4) Dolby E passthrough lacks interoperability and Adtec deems it as very fragile because there is no control or monitoring at the transport layer nor lip sync adjustment per Dolby E stream; they are grouped in pairs of Dolby E. Simply put, they adjust the PID therefor both audios get the same adjustment. I would argue that Adtec and NTT can both passthrough two (2) Dolby E payloads. The Adtec advantage is the ability to pass two (2) and still encode two (2) MPEG 1 Layer 2 audios.

…for more on MPEG Encoders