CHAPTER 8. Conclusions and Future Works
8.2 Future Works
The proposed encoder in this thesis is mainly concentrate in C code level, to be more adapted to embedded system applications, converting it into assembly code and perform further optimization accordingly is necessary. In this way, the proposed AAC encoder can get even better performance. Also, at present, we haven’t paid much attention to the memory usage optimization. However, this is quite important in those resource limited systems. Thus, these are two essential works in the future.
We can see that selling music in digitalized format through Internet rather than selling CDs in record stores seems to be an irresistible trend. Though AAC itself has the advantages of smaller file size and better quality, to convince traditional music company taking AAC format as the distributing standard is not enough. Thus, corresponding encryption should be implemented as well. Together with data embedded algorithm and encryption, AAC can be the first choice of standard format delivery music through Internet.
To further expand the application of this thesis, the concepts proposed can be
AC-3, MPEG-1 Layer III, Microsoft® WMA, and Ogg Vorbis, to increase their performance, too. Especially, MPEG-2 AAC constitutes the kernel of MPEG-4 General Audio (GA). MPEG-4 GA generally based on MPEG-2 AAC structure and with some enhancement and refinement. What have been standardized in MPEG-2 AAC, including low complexity (LC) profile, main profile and scalable sampling rate (SSR) profile, are also presented in MPEG-4 AAC. Thus, the proposed algorithm is most suitable for optimizing MPEG-4 audio.
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APPENDIX A. Advantech PCM-7130 SBC
The PCM-7130 is an Intel® StrongARM low-power RISC processor single board computer that is designed to serve power/environment critical applications. Fig. A.1 shows the appearance of the entire system.
Fig. A. 1 The appearance of the Advantech PCM-7130 SBC [37]
The brief specifications are shown as following [35]:
CPU: Intel® StrongARM SA-1110, 206 MHz Flash memory: up to 32 MB flash memory on board Memory: 64 MB SDRAM on board
Watchdog timer: Dallas DS1670 Audio: AC’97 stereo audio interface Dimensions: 145 x 102 mm
Gross weight: 0.2 kg (0.4 lb.)
SSD: 1 type-II CompactFlash™ card slot
DIO: 8 digital inputs, 8 digital outputs Ethernet: 1 RJ-45 10Base-T port GPIO: 8
IrDA: 1 IrDA interface
PCMCIA: 1 type-II PCMCIA slot
PS/2 port: 1 PS/2 port for keyboard/mouse
Serial ports: 2 full RS-232 ports and 1 RS-485 port with automatic data flow control
USB ports: 1 USB host and 1 USB client ports Display Chipset: Epson S1D13806 VGA controller
LCD interface: 18-bit TFT active color LCD/16 bit DSTN passive color LCD;
20-pin header for 18-bit LVDS interface TV-out: supports both NTSC and PAL output
Touchscreen: supports 4-wire resistive touchscreen via SPI (Serial Peripheral Interface)
FCC Class A certified CE certified
Fig. A.2 gives a more detailed view of PCM-7130 with its peripheral interface.
Fig. A. 2 Advantech PCM-7130 SBC [37]