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News Release from: Tensilica | Subject: Xtensa HiFi 2 audio engine
Edited by the Electronicstalk Editorial
Team on 07 October 2005
Embedded audio processor moves up to
24bit
The Xtensa HiFi 2 audio engine is a new an addon package for Tensilica's proven Xtensa LX processor, optimised specifically for today's consumer audio functions.
The Xtensa HiFi 2 audio engine is a new an addon package for Tensilica's proven Xtensa LX processor, optimised specifically for today's consumer audio functions Tensilica has also announced a comprehensive set of software encoders and decoders for all popular audio standards, including Dolby Digital AC-3, microQ from QSound Labs, MP3, MPEG-2/4 AAC LC and aacPlus, WMA (Windows Media Audio) and AMR (adaptive multirate speech)
This article was originally published on Electronicstalk on 29 Jun 2006 at 8.00am (UK)
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The Xtensa HiFi 2 audio engine drives the high-quality 24bit audio processing in the recently introduced Nvidia GoForce 5500 handheld graphics processing unit.
Audio cores add Ogg Vorbis support
Tensilica has added an Ogg Vorbis decoder for its popular Xtensa HiFi 2 audio engine and Diamond 330HiFi processor core.
As a low-power turnkey solution, the Xtensa HiFi audio engine enables system-on-chip (SoC) designers to quickly design audio-enabled devices such as cellular phones, portable music players, DVD drives, and set-top boxes.
"By the end of 2005, our customers will have shipped tens of millions of units that include our first-generation Xtensa HiFi audio engine", said Chris Rowen, President and CEO of Tensilica.
"This new generation product supports additional audio standards and is based on our leading-edge Xtensa LX processor, so it's faster, lower power, smaller and more flexible".
Further reading
Optimised decoder cuts power budget for MP3
Tensilica has produced an optimised version of the industry-standard MP3 decoder for its Xtensa HiFi 2 Audio Engine and Diamond Standard 330HiFi processor core.
Audio core supports latest Dolby encoders
Encoders enable manufacturers to design consumer devices that support Dolby 5.1-channel surround sound as well as next-generation HD video technologies.
Top score posted for licensable processor core
Tensilica has announced that it has posted the highest score ever recorded for a licensable processor core, and the highest absolute score ever published for any processor on EEMBC.
This new 24bit embedded audio processor has inherent advantages over common 16bit audio processors in use today.
It provides superior sound quality of compressed files due to the increased precision available for intermediate calculations in the compression and decompression algorithms.
And 24bit audio is fully compatible with all of the popular audio standards.
Because the Xtensa LX processor with the HiFi 2 audio engine is fully programmable, multiple audio standards can run on the same hardware, allowing the same silicon to be used for multiple applications or the same device to play or record audio in different standards.
Tensilica offers 16 audio packages for the Xtensa HiFi 2 audio engine, so these functions can be integrated into an SoC design, with no additional codec software development required.
Dolby Digital AC-3 decoder: implements the complete Dolby Digital AC-3 audio decoder with multichannel 5.1 decoding.
It supports all standard down-mix modes and the full range of bit and sample rates.
Dolby Digital AC-3 Consumer encoder (DDCE): implements the consumer version of the Dolby Digital encoder, supporting one- and two-channel encoding over the full range of bit and sample rates.
Dolby Digital Plus Consumer decoder: implements the complete Dolby Digital Plus Consumer decoder with multichannel 5.1 decoding as well as the Dolby Digital convertor for compatibility with existing Dolby Digital 5.1 receivers.
It supports all standard down-mix modes and the full range of bit and sample rates.
QSound microQ components: implements QSound's microQ audio components - a midi wavetable synthesis engine with a scalable sample set, a multichannel stereo mixer, a wide range of processes to control frequency response, dynamics and spatial enhancements, as well as full 3D positional audio for games.
MP3 decoder: implements MPEG-1, MPEG-2 and MPEG-2.5 (extensions of MPEG-1) layer 1/2/3 (MP3) decoding with support for constant bitrate, variable bitrate and free formats.
Also, it is fully compliant with ISC/IEC 11172-4.
MP3 encoder: implements MPEG-1, MPEG-2 and MPEG-2.5 (extensions of MPEG-1) layer 1/2/3 (MP3) encoding with support for joint stereo coding for better efficiency and support for the constant bit rate format.
MPEG-4 aacPlus v2 decoder: implements aacPlus v2 decoding which includes support for parametric stereo (PS) and SBR and is compliant with the 3GPP specifications for Enhanced aacPlus.
MPEG-4 aacPlus v2 encoder: implements aacPlus v2 encoding which includes support for parametric stereo (PS) and SBR and is compliant with the 3GPP specifications for Enhanced aacPlus.
MPEG-4 aacPlus v1 decoder: implements aacPlus v1 decoding which includes support for spectral band replication (SBR) and is compliant with the 3GPP specifications for Enhanced aacPlus.
MPEG-4 aacPlus v1 encoder: implements aacPlus v1 encoding which includes support for spectral band replication (SBR) and is compliant with the 3GPP specifications for Enhanced aacPlus.
MPEG-2/4 AAC LC decoder: implements MPEG-2/4 AAC decoding compliant with ISO/IEC 13818-4 and 14496-4.
It supports the decoding of MPEG-2/4 AAC LC and LC multichannel files as well as the decoding of ADIF, ADTS, MPEG-2 and MPEG-4 file format data streams.
MPEG-2/4 AAC LC encoder: implements MPEG-4 AAC LC and MPEG-2 AAC LC 2-channel encoding.
It supports constant bitrate, variable bitrate, TNS, PNS, joint stereo etc.
It also supports ADIF and ADTS encoding formats.
WMA decoder: implements decoding of high-, mid- and low-rate WMA data streams as well as the decoding of ASF (Advanced Streaming Format) data streams and is fully compliant with Microsoft WMA test specifications.
WMA encoder: implements encoding of high-, mid- and low-rate WMA data streams as well as the encoding of ASF (Advanced Streaming Format) data streams and is fully compliant with Microsoft WMA test specifications.
AMR narrowband speech codec: implements AMR narrowband speech decoding and encoding and is fully compliant with the 3GPP specifications for the AMR NB codec.
AMR wideband speech codec: implements AMR wideband speech decoding and encoding and is fully compliant with the 3GPP specifications for the AMR WB codec.
The Xtensa HiFi 2 Audio Engine employs over 300 audio-specific DSP instructions, created specifically by the engineers at Tensilica to optimise the Xtensa LX processor for audio.
It features a dual MAC (multiply accumulate) architecture supporting both 24x24 and 32x16bit arithmetic on both MAC units.
The Xtensa HiFi2 audio engine employs Tensilica's FLIX (flexible length instruction extension) technology to provide an efficient architecture to minimise cycle consumption and power for audio applications.
This extends the base Xtensa LX configurable processor with a 64bit instruction format containing dual multiply/accumulate and other DSP operations as well as loads and stores to and from two register files specific to the Xtensa HiFi 2 engine.
Numerous features such as saturation, fractional arithmetic, and signedness can be selected with the multiply/accumulate and arithmetic operations to ease codec porting and implementation effort.
Also provided are operations to facilitate bit stream access and variable-length (Huffman) encoding and decoding.
The Xtensa HiFi 2 audio engine's native 24bit data precision provides a superior tradeoff between sound quality and codec performance compared with many common 16bit audio processors in use today, and support for 32 and 16bit data items is also provided.
And the HiFi2 audio engine is fully compatible with all industry standard audio coding formats, and delivers noticeably superior sound quality even when decoding prerecorded 16bit encoded music files.
Through a combination of significantly lower power per megahertz, and architectural optimisation of the new Xtensa HiFi 2 audio engine instruction set, the Xtensa HiFi 2 audio engine delivers dramatic improvements in energy efficiency that lead to increased battery life for portable and wireless applications.
Based on TSMC's 0.13um LV process, running at 200MHz, static power for the Xtensa HiFi 2 audio engine is 0.40mW, dynamic power is 17.8mW, and total power is 18.2mW or 0.091mW/MHz.
Total power for the first Xtensa HiFi audio engine was 0.207mW/MHz in the same process.
Tensilica's first HiFi audio engine's worst case required operating frequency for the MPEG-4 AAC LC encoder is 85MHz, whereas the worst case required frequency for the MPEG-4 AAC LC encoder with the new Xtensa HiFi 2 audio engine is just 38MHz.
The total energy used for this example (clock frequency required times power-per-megahertz) is a nearly 5x improvement in energy efficiency.
Through careful engineering, and by fully exploiting the new features of the Xtensa LX architecture, Tensilica was able to reduce the overall gate count of the Xtensa HiFi 2 audio engine, compared with the first version, resulting in a 20% smaller size when targeted to 200MHz.
Total gate count, with the 300 audio-specific instructions, is approximately 78K gates.
Because of the efficiency of the Xtensa HiFi 2 audio engine architecture, it requires only a fraction of the available clock frequency to perform the audio decoding and encoding functions.
Targeting high-performance applications, it can support speeds greater than 280MHz in TSMC 0.13um LV, leaving lots of headroom for other control, media and signal processing tasks.
The Xtensa HiFi 2 audio engine is available now and priced at $75,000 for the audio instruction set.
The following software codecs are available now: MP3 encode/decode, MPEG 2/4 AAC LC encode/decode, AMR WB encode/decode and the microQ midi synthesiser.
Others will be available over the next two months.
Codecs are priced separately, starting at $37,500 for object code implementations of the MP3 decoder.
Use of the Xtensa HiFi2 audio engine requires a licence for the Xtensa LX processor.
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