3 : xhe-aac (Bongho Lee et al.: A Study on the Variable Transmission of xhe-aac Audio Frame) (Special Paper) 21 3, 2016 5 (JBE Vol. 21, No. 3, May 2016) http://dx.doi.org/10.5909/jbe.2016.21.3.357 ISSN 2287-9137 (Online) ISSN 1226-7953 (Print) xhe-aac a), a), a), a) A Study on the Variable Transmission of xhe-aac Audio Frame Bongho Lee a), Kyutae Yang a), Hyoungsoo Lim a), and Namho Hur a) DAB+ HE-AAC v2. USAC xhe-aac.... Abstract In DAB+, HE-AAC v2 codec is applied for the fixed rate transmission of audio stream. In case that xhe-aac codec including USAC, a more efficiency is expected when the variable frame is used in a given same bandwidth compared to the fixed frame transmission. For this to be realized, audio streams need to be multiplexed in a sub-channel before transmission, then a method is required to identify the border of each audio frames. In this paper, the toggled sync byte and additional identification field being sequentially placed between AU borders are proposed in order to deal with the AU border identification. In addition, the Reed-Solomon based error correction code which is compliant to DAB+ is proposed. Keyword : Digital radio, DAB+, HE-AAC v2, xhe-aac, FEC a) (Electronics Telecommunications Research Institute) Corresponding Author : (Bongho Lee) E-mail: leebh@etri.re.kr Tel: +82-42-860-1030 ORCID: http://orcid.org/0000-0002-4502-1361 [R0166-15-1028, ] [B0101-15-0136, USAC ]. IWAIT 2016. Manuscript received March 22, 2016; Revised May 17, 2016; Accepted May 17, 2016.. DAB [1] MPEG II HE-AAC v2(high-efficiency Advanced Audio Coding version 2) DAB+ [2] 2008. DAB+. DAB+
(JBE Vol. 21, No. 3, May 2016) HE-AAC v2. DAB+ 120ms..,. DRM+(Digital Radio Mondiale plus) [3] xhe-aac (extended HE-AAC). DRM+ DAB HE-AAC v2 xhe-aac.. xhe-aac DAB+, DRM+. 2 MPEG MPEG audio transport [4], MPEG-2 TS[5], DAB+ DRM+. xhe-aac DAB+.,,,.. MPEG.. MPEG-2 TS,.. (AU: Access Unit). (PAD: Program Associated Data). 1. MPEG Audio Transport MPEG AAC ADTS(Audio Data Transport Stream) MPEG-4 LATM(Low-overhead MPEG-4 Audio Transport Multiplex) LOAS(Low Overhead Audio Stream). MPEG-4 LATM LOAS AAC AAC-LD(AAC Low Delay) AAC-ELD v2(aac Enhanced Low Delay) [4]. 1 (elementary stream) (ASC: Audio Specific Config). ASC audio object type sampling rate, frame length audio channel arrange-
3 : xhe-aac (Bongho Lee et al.: A Study on the Variable Transmission of xhe-aac Audio Frame) 1. HE-AAC v2 audio specific coding Fig 1. Audio specific coding bitstream structure of HE-AAC v2 ment. ASC. ASC. DAB+ MPEG Surround. xhe-aac ASC.. AAC (AU: Access Unit) 2. ADTS[6] 3 ADTS ADTS,. (syncword).. (fixed header section) 12. MPEG-2 TS 0x47 (sync sequence) 1111 1111 1111. sampling_frequency_index. 8k ~ 96k 12 index. Channel configuration 0 ISO/IEC 13818-7 part 7 [6] table 42. AAC frame length buffer fullness 2. AAC Fig 2. Access unit structure of AAC stream
(JBE Vol. 21, No. 3, May 2016) 3. MPEG Fig 3. Transport stream structure of MPEG audio data. aac_frame_length. adts_buffer_fullness ADTS bit reservoir. raw_data_block() 1024. ADTS xhe-aac DAB DAB. syncword, channel configuration, aac frame length, buffer fullness channel configuration stereo. MPEG Surround channel configuration MPEG Surround. 2. MPEG-2 TS MPEG-2 TS [5] DMB(Digital Multimedia Broadcasting) 188. 4 xhe-aac TS PES(Packetized Elementary Stream). MPEG-2 TS 4 AU PES 6 4. MPEG-2 TS Fig 4. Structure of MPEG-2 TS format
3 : xhe-aac (Bongho Lee et al.: A Study on the Variable Transmission of xhe-aac Audio Frame). xhe-aac MPEG-2 TS/PES TS 4 PES 6. 3. DAB+ DAB MPEG-1,2 DAB 5. MUSICAM MPEG II DAB DAB. DAB (PAD: Program Associated Data) X-PAD F-PAD. MUSICAM MPEG FEC. HE-AAC v2 DAB+ 2008 HE-AAC v2 FEC. DAB+ 6. DAB+, DAB. DAB+, 64kbps, 18, 48kbps 24. 120ms DAB.. firecode dac_rate, sbr_flag, aac_channel_mode, ps_flag, mpeg_surround_config au_start.. 6 firecode dac_rate DAC 5. MUSICAM Fig 5. Transmission frame structure of MUSICAM 6. DAB+ Fig 6. Structure of DAB+ audio super frame
(JBE Vol. 21, No. 3, May 2016) (Digital to Analog Converter) 32kHz 48kHz sbr_flag SBR(Spectral Band Replication). aac_channel_ mode parametric stereo ps_flag. MPEG Surround mpeg_surround_flag. AU au_start.. xhe-aac.. DAB+. 4. DRM+ DRM [3] AAC USAC(Unified Speech and Audio Coding) xhe-aac. xhe- AAC. AAC 15. DRM+. 7(a) DRM+ DAB+. 7. DRM+ Fig 7. Structure of DRM+ audio super frame
3 : xhe-aac (Bongho Lee et al.: A Study on the Variable Transmission of xhe-aac Audio Frame) 2. frame border index frame border count 16 frame border count 4 frame border index 12. Frame border index. 7(b) 4 border description 3... xhe-aac DAB+ xhe-aac 24kbps. DAB USAC xhe- AAC [7]. xhe-aac DAB+ DAB. DAB+. [7] DRM+. MPEG-2 TS. MPEG-2 TS (elementary stream) xhe-aac. MPEG-2 TS AU. (FEC: Forward Error Correction) Reed-Solomon virtual interleaving. 1. DRM+., DAB+ xhe-aac 8. Fig 8. Structure of proposed audio super frame
(JBE Vol. 21, No. 3, May 2016). 8 (AU). DAB+. (toggling) (ATP: Audio Transport Packet) [8]. 2. ATP ATP RS 110. 9 ATP ATP1 1 ATP2, AFn+1 2. ATP. 9. Fig 9. Structure of audio transport packet 10. Fig 10. Types of audio transmission packet
3 : xhe-aac (Bongho Lee et al.: A Study on the Variable Transmission of xhe-aac Audio Frame) ATP 10 3. 1 (sync byte) 4 AU border count AU border index. MPEG-2 TS 0x47 1 1 8.., 0x47 0x74 9, ATP1 0x47 ATP2 0x47 ATPn 0x74. ATP.. C 21. 2, 4 6 stuffing AU border count 2. 2. AU border count Table 2. Generated bits in accordance with the AU border count AU border count number of bits without stuffing number of byte alligned number of bits alligned stuffing bits 1 14 2 16 2 2 24 3 24 0 3 34 5 40 6 4 44 6 48 4 5 54 7 56 2 6 64 8 64 0 7 74 10 80 6 8 84 11 88 4 9 94 12 96 2 10 104 13 104 0 11 114 15 120 6 12 124 16 128 4 13 134 17 136 2 14 144 18 144 0 15 154 20 160 6 1. Table 1. Sync bytes 0x47 (01000111) 0x74 (01110100) 0x8E (10001110) 0xE8 (11101000) 0x1D (00011101) 0xD1 (11010001) 0x3A (00111010) 0xA3 (10100011) 9 ATP2. B ATP 3 9 ATP1 ATPn+1. C AU border count 4 16. DRM+ 3. 8 1, CU(Capacity Unit) FEC. DAB+ Reed- Solomon (Virtual Interleaving). RS 11 DAB+[2] (120,110,t=5). FEC ATP 12 (sub-channel index) (column).
(JBE Vol. 21, No. 3, May 2016) 11. Reed-Solomon Fig 11. Reed-Solomon code 12. FEC Fig. 12. FEC and the transmission order 110. RS 110 10 110. S1 S110, F1~F10. RS.. DAB+ xhe-aac. DAB+ DRM+ MPEG-2 TS ATP. ATP xhe- AAC. PES
3 : xhe-aac (Bongho Lee et al.: A Study on the Variable Transmission of xhe-aac Audio Frame). DAB+ DRM+. (References) [1] ETSI EN 300 401 V1.4.1 (2006-06), Radio Broadcasting Systems; Digital Audio Broadcasting (DAB) to mobile, portable and fixed receivers. [2] ETSI TS 102 563 V1.2.1 (2010-05), Digital Audio Broadcasting (DAB); Transport of Advanced Audio Coding (AAC) Audio. [3] ETSI ES 201 980 V4.1.1 (2014-01), Digital Radio Mondiale (DRM); System Specification. [4] ISO/IEC JTC1/SC29/WG11 N14751, AAC Transport Formats, July, 2014. [5] ISO/IEC 13818-1, Information technology Generic coding of moving pictures and associated audio information: Systems. [6] ISO/IEC 13818-7, Information technology Generic coding of moving pictures and associated audio information - Part 7: Advanced Audio coding (AAC) [7] Kyutae Yang, Seungkwon Beack, Bongho Lee, Hyoungsoo Lim, A Study on USAC Transport Mechanism for Digital Audio Broadcasting Plus, Korean Society of Broadcast Engineers, Summer Conference, July, 2015. [8] Bongho Lee, Kyutae Yang, myung-sun Baek, Jaeeun Jeong, Hyeoungsoo Lim, Namho Hur, USAC Stream Delivery over Digital Radio Network, International Workshop on Advanced Image Technology, January, 2016. - 1997 2 : - 1999 2 : - 1999 ~ : (ETRI) - ORCID : http://orcid.org/0000-0002-4502-1361 - :,, - 1986 2 : - 1991 2 : - 1991 2 ~ : (ETRI) - ORCID : http://orcid.org/0000-0003-1435-5032 - :, - 1992 2 : - 1994 2 : - 1999 2 : - 1999 ~ : (ETRI) - : FTN,,,, LAN/MAN/PAN
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