05-03-2013, 03:25 PM
IP VIDEO DOOR PHONE
[attachment=52667]
INTRODUCTION
Audio Video Door Phone Systems are fast becoming de rigueur in office buildings, residential complexes,
villas and bungalows. Technological advances in multimedia and embedded systems in general such as
camera sensor technology and real time video encoding & decoding technologies, have made it
commercially viable for current day security solutions to incorporate video and become a true
multimedia solution.
Calsoft Labs is a product engineering services company that specializes in the three niche areas of
Networking and Datacom, Embedded Systems and ISVs. Calsoft Labs is uniquely positioned to offer its
customers the best of both worlds – the personalized services offered by a small company combined with
the technical know-how and capability of a larger company.
As a one stop solution house for embedded products, Calsoft Labs' typical engagement ranges from
product requirement scoping, system design and development to deployment and maintenance
including the mechanical and plastic components of the solution. On the technology front, we have
expertise in a wide range of domains from high-speed hardware boards design, to firmware, OS, driver
and other components of board support packages. This also includes design and development of target
applications and host side applications that generally run on PCs.
IP Video Door Phone System
The IP Video Door Phone System supports video capture and streaming from Entry Units to Apartment
Units as well as two way audio conversations via an on-board microphone and speaker. One can make a
call to an Apartment Block via Entry Units placed at the doors and the call can be answered by any of the
Apartment Units in that block.
Both Entry Units and Apartment Units have LCD displays with built-in Touch-Screen interface and
keypads. An Entry Unit is mounted with a CMOS camera module and the SoC of both units have integrated
hardware accelerators for video encoding and decoding. Thus one can experience real time video
streaming at full frame rate from Entry Units to Apartment Units. The LCD (customizable to required
resolution) and the touch screen interface provide a rich GUI experience similar to those in smart phones
available today. The presence of an AEC (Acoustic Echo Cancellation) chip on the audio path handles any
acoustic echoes that are generated by such a system and ensures that the listener will never hear the echo
of his own voice. The Apartment Units may support a standard off-the-shelf telephone handset, or can be
hands-free.
The GUI subsystem is based on QT 4.6 which is an open-source distribution under Nokia support or GTK.
These are proven platforms that provide rich set of application building blocks and deliver all of the
functionality needed to build advanced cross platform applications. The IP Video Door Phone System is a
scalable system and supports various deployment scenarios - such as one unit to multiple units or one to
one or many to many units.
System Block Diagram
Both Entry Units and Apartment Units are based on the same ARM based, multimedia System-on-Chip (SoC), with
hardware acceleration for image processing, video encode and decoding. SoC also includes most of the peripheral
controllers built within. Both units use DDRAM based memory and NAND Flash based storage.
Design Considerations
Demands of Video Processing
Video processing involves complex and computationally intensive Video Encode/ Decode compression algorithms
that need to be executed in real time under demanding time constraints. This is apart from host of other algorithms
required to carry out image processing functionalities on captured image data from camera sensor to improve the
quality of the image. In addition to these inherent complexities, the tasks have to be carried out in real-time. For
better viewing experience, video needs to be streamed and played back at higher Frames per Second (FPS).
Video Encode / Decode – Clock requirement
Embedded application processors, like ARM, are designed to cater to a wide range of general embedded
applications. Most of these applications are not computationally intensive mathematical algorithms like video
encode and decode. However as a general application processor, it does support video encode and decode. It is
sometimes used for such applications, but usually at the lowest resolutions and FPS, though at a cost that results in
a greater load on the CPU.
A study by a group on ARM architecture indicates that the clock requirement on ARM920T for MPEG-4 algorithms
for QCIF (176 x 144 pixels - Quarter CIF) at 15 FPS is 47 MHz for encode and 10 MHz for decode. One should note that
these algorithms do not cover many other algorithms involved in image processing.
QCIF is meant for mobile handsets and cannot be used for Video Door Phone applications as the latter requires
higher resolutions and higher FPS. Extrapolating the above clock measurements for QVGA (320x240) at 30 FPS one
will get numbers like 280 MHz and 90 MHz. This clearly rules out the possibility of running the video encoder and
decoders on ARM and indicates the need for dedicated hardware accelerators to perform video encode and decode
compression algorithm operations. Further image processing algorithms will also need such modules in the
hardware. These hardware accelerators need to be tightly integrated with the other video, DMA, memory
subsystem within the CPU. This makes the choice of CPU critical for the IP Video application.
[attachment=52667]
INTRODUCTION
Audio Video Door Phone Systems are fast becoming de rigueur in office buildings, residential complexes,
villas and bungalows. Technological advances in multimedia and embedded systems in general such as
camera sensor technology and real time video encoding & decoding technologies, have made it
commercially viable for current day security solutions to incorporate video and become a true
multimedia solution.
Calsoft Labs is a product engineering services company that specializes in the three niche areas of
Networking and Datacom, Embedded Systems and ISVs. Calsoft Labs is uniquely positioned to offer its
customers the best of both worlds – the personalized services offered by a small company combined with
the technical know-how and capability of a larger company.
As a one stop solution house for embedded products, Calsoft Labs' typical engagement ranges from
product requirement scoping, system design and development to deployment and maintenance
including the mechanical and plastic components of the solution. On the technology front, we have
expertise in a wide range of domains from high-speed hardware boards design, to firmware, OS, driver
and other components of board support packages. This also includes design and development of target
applications and host side applications that generally run on PCs.
IP Video Door Phone System
The IP Video Door Phone System supports video capture and streaming from Entry Units to Apartment
Units as well as two way audio conversations via an on-board microphone and speaker. One can make a
call to an Apartment Block via Entry Units placed at the doors and the call can be answered by any of the
Apartment Units in that block.
Both Entry Units and Apartment Units have LCD displays with built-in Touch-Screen interface and
keypads. An Entry Unit is mounted with a CMOS camera module and the SoC of both units have integrated
hardware accelerators for video encoding and decoding. Thus one can experience real time video
streaming at full frame rate from Entry Units to Apartment Units. The LCD (customizable to required
resolution) and the touch screen interface provide a rich GUI experience similar to those in smart phones
available today. The presence of an AEC (Acoustic Echo Cancellation) chip on the audio path handles any
acoustic echoes that are generated by such a system and ensures that the listener will never hear the echo
of his own voice. The Apartment Units may support a standard off-the-shelf telephone handset, or can be
hands-free.
The GUI subsystem is based on QT 4.6 which is an open-source distribution under Nokia support or GTK.
These are proven platforms that provide rich set of application building blocks and deliver all of the
functionality needed to build advanced cross platform applications. The IP Video Door Phone System is a
scalable system and supports various deployment scenarios - such as one unit to multiple units or one to
one or many to many units.
System Block Diagram
Both Entry Units and Apartment Units are based on the same ARM based, multimedia System-on-Chip (SoC), with
hardware acceleration for image processing, video encode and decoding. SoC also includes most of the peripheral
controllers built within. Both units use DDRAM based memory and NAND Flash based storage.
Design Considerations
Demands of Video Processing
Video processing involves complex and computationally intensive Video Encode/ Decode compression algorithms
that need to be executed in real time under demanding time constraints. This is apart from host of other algorithms
required to carry out image processing functionalities on captured image data from camera sensor to improve the
quality of the image. In addition to these inherent complexities, the tasks have to be carried out in real-time. For
better viewing experience, video needs to be streamed and played back at higher Frames per Second (FPS).
Video Encode / Decode – Clock requirement
Embedded application processors, like ARM, are designed to cater to a wide range of general embedded
applications. Most of these applications are not computationally intensive mathematical algorithms like video
encode and decode. However as a general application processor, it does support video encode and decode. It is
sometimes used for such applications, but usually at the lowest resolutions and FPS, though at a cost that results in
a greater load on the CPU.
A study by a group on ARM architecture indicates that the clock requirement on ARM920T for MPEG-4 algorithms
for QCIF (176 x 144 pixels - Quarter CIF) at 15 FPS is 47 MHz for encode and 10 MHz for decode. One should note that
these algorithms do not cover many other algorithms involved in image processing.
QCIF is meant for mobile handsets and cannot be used for Video Door Phone applications as the latter requires
higher resolutions and higher FPS. Extrapolating the above clock measurements for QVGA (320x240) at 30 FPS one
will get numbers like 280 MHz and 90 MHz. This clearly rules out the possibility of running the video encoder and
decoders on ARM and indicates the need for dedicated hardware accelerators to perform video encode and decode
compression algorithm operations. Further image processing algorithms will also need such modules in the
hardware. These hardware accelerators need to be tightly integrated with the other video, DMA, memory
subsystem within the CPU. This makes the choice of CPU critical for the IP Video application.