'회사일/uclinux & rtos'에 해당되는 글 7건

  1. 2016.01.06 lwip RTSP over HTTP 가능성?
  2. 2016.01.06 freeRTOS + lwip or freeRTOS+TCP
  3. 2015.11.12 비선점형 마이컴 OS - csrtos
  4. 2015.11.11 uclinux / linux 벤치마킹
  5. 2015.11.11 µC/OS-II
  6. 2015.11.10 uclinux
  7. 2015.11.10 freeRTOS / OpenRISC
회사일/uclinux & rtos2016. 1. 6. 15:49


아직까지는 찾지를 못함..

직접 구현해야 하려나?


mjpeg 카메라 영상인데...

[링크 : http://141.89.114.98/demo/edu640x480v.html] mjpeg 예제


안드로이드(갤S2 LTE HD)는 그냥 다운로드..(재생불가)

IE 11 (edge)재생불가

IE 10 이하 재생불가


아이패드는 재생

크롬 재생

VLC 재생


It is natively supported by the QuickTime Player, the PlayStation console, and web browsers such as Safari, Google Chrome, and Mozilla Firefox.

[링크 : https://en.wikipedia.org/wiki/Motion_JPEG]


M-JPEG over HTTP

HTTP streaming separates each image into individual HTTP replies on a specified marker. RTP streaming creates packets of a sequence of JPEG images that can be received by clients such as QuickTime or VLC.


In response to a GET request for a MJPEG file or stream, the server streams the sequence of JPEG frames over HTTP. A special mime-type content type multipart/x-mixed-replace;boundary=<boundary-name> informs the client to expect several parts (frames) as an answer delimited by <boundary-name>. This boundary name is expressly disclosed within the MIME-type declaration itself. The TCP connection is not closed as long as the client wants to receive new frames and the server wants to provide new frames. Two basic implementations of a M-JPEG streaming server are cambozola and MJPG-Streamer. The more robust ffmpeg-server also provides M-JPEG streaming support.

[링크 : https://en.wikipedia.org/wiki/Motion_JPEG#M-JPEG_over_HTTP]


VLC로 raw 덤프해서 보니...

--myboundary

Content-type: image/jpeg

이렇게 시작하고 그 아래로는 깨지는걸 봐서는 그냥 jpeg 프레임인듯..



심심..(?)해서 저기 MIME 관련 헤더들 삭제하고 jpeg으로 저장하니

아래와 같이 똮!



저장을 좀 오래 하니

--myboundary

Content-type: image/jpeg

가 반복적으로 나타난다.


video/x-jpegMotion-JPEG video.   There are currently no specific properties defined or needed for this type. Note that video/x-jpeg only applies to Motion-JPEG pictures (YUY2 colourspace). RGB colourspace JPEG images are referred to as image/jpeg (JPEG image).

[링크 : http://gstreamer.freedesktop.org/.../section-types-definitions.html#table-video-types]

    [링크 : http://stackoverflow.com/.../correct-mime-type-for-multipart-mjpeg-stream-over-http]




HTTP/1.0 200 OK

Server: en.code-bude.net example server

Cache-Control: no-cache

Cache-Control: private

Content-Type: multipart/x-mixed-replace;boundary=--boundary

 

--boundary

Content-Type: image/jpeg

Content-Length: [length of the image bytes]

 

[write jpeg bytes]

 

--boundary

Content-Type: image/jpeg

Content-Length: [length of the image bytes]

 

[write jpeg bytes]

 

[...] 


[링크 : http://en.code-bude.net/tag/how-does-mjpeg-work/]



mjpeg streamer

[링크 : http://www.acmesystems.it/video_streaming]

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Posted by 구차니
회사일/uclinux & rtos2016. 1. 6. 15:16

두개에 대한 벤치마크는 안보이지만...

어느걸 택하던 상관없다 일려나?(좋은 의미던 나쁜 의미던..)


lwIP


lwIP is also a good stack when used in its intended, memory constrained, environment. It has a higher throughput than uIP, but also has a larger ROM and RAM footprint. Although the footprint is larger than uIP it is still smaller than most commercial TCP/IP offerings. In particular, lwIP saves RAM by making large data buffers by chaining smaller buffers together.

Most (if not all) the FreeRTOS demos listed here make use of quite an old lwIP version. There are however contributed demos available in the FreeRTOS Interactive forums that use a more up to date lwIP code base. Further lwIP related uploads would be gratefully received.


On the negative side, lwIP is undeniably quite complex to use at first, but time invested in its use will pay dividends in future projects. lwIP is also a moving target because it is constantly being developed and updated (which is not necessarily a negative thing).


[링크 : http://www.freertos.org/embeddedtcp.html]

[링크 : http://lwip.wikia.com/wiki/LwIP_Application_Developers_Manual]

[링크 : http://lwip.wikia.com/wiki/LwIP_Wiki]

freeRTOS+TCP 패키지

[링크 : http://www.freertos.org/FreeRTOS-Plus/FreeRTOS_Plus_TCP/index.html]

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Posted by 구차니
회사일/uclinux & rtos2015. 11. 12. 15:18

원본을 찾기 힘드네...

그런데 비선점도 rtos가 될 수 있는건가?


[링크 : http://www.mtcnet.net/~henryvm/4AvrOS/]

    [링크 : http://roboticslab.tistory.com/6]

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Posted by 구차니
회사일/uclinux & rtos2015. 11. 11. 11:12

ppt 에 추가된 내용으로

부팅 시간이

linux 2.6.7 - 437.11

uclinux 2.6.7 - 415.16

으로 22초 정도 단축된다.


context switching 에 소요되는 시간인

linux - avg 110us

uclinux - avg 20us

에 비하면... 의외로 미미한 수준?


MMU 지원을 받지 못해 소스를 수정해야 하는 오버헤드를 생각하면

그리 큰 성능향상이라고 하긴 그럴 듯..


[링크 : http://bit.sparcs.org/~gangster/publication/uc_linux_fall.ppt]

[링크 : http://opensrc.sec.samsung.com/document/uc-linux-04_sait.pdf]

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Posted by 구차니
회사일/uclinux & rtos2015. 11. 11. 08:39


[링크 : http://micrium.com/rtos/ucosii/overview/]

[링크 : https://www.csie.ntu.edu.tw/~d6526009/ucOS2/Chapter-1.pdf]


+

[링크 : http://repilria.tistory.com/382]

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회사일/uclinux & rtos2015. 11. 10. 09:11

What is uClinux?


The original uClinux was a derivative of Linux 2.0 kernel intended for microcontrollers without Memory Management Units (MMUs). However, the Linux/Microcontroller Project has grown both in brand recognition and coverage of processor architectures. Today's uClinux as an operating system includes Linux kernel releases for 2.0 2.4 and 2.6 as well as a collection of user applications, libraries and tool chains.


[링크 : http://www.uclinux.org/description/]

[링크 : http://www.uclinux.org/]


[링크 : http://www.uclinux.org/pub/uClinux/]

[링크 : http://sourceforge.net/projects/uclinux/]


[링크 : https://wiki.kldp.org/wiki.php/WhyIsMallocDifferentUnderUclinux]


[링크 : http://goo.gl/pzUmg] atmega1284p uclinux



+

[링크 : https://wiki.kldp.org/wiki.php/%B8%AE%B4%AA%BD%BA%C4%BF%B3%CE#s-5]

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회사일/uclinux & rtos2015. 11. 10. 09:05


FreeRTOS is designed to be small and simple. The kernel itself consists of only three or four C files. To make the code readable, easy to port, and maintainable, it is written mostly in C, but there are a few assembly functions included where needed (mostly in architecture-specific scheduler routines).


Supported architectures

ARM architecture

 ARM7

 ARM9

 ARM Cortex-M0

 ARM Cortex-M0+

 ARM Cortex-M3

 ARM Cortex-M4

 ARM Cortex-A

Atmel

 Atmel AVR

 AVR32

 SAM3

 SAM4

 SAM7

 SAM9

 SAM D20

 SAM L21

Intel

 x86

 8052


[링크 : https://en.wikipedia.org/wiki/FreeRTOS]

[링크 : http://www.freertos.org/]

[링크 : http://sourceforge.net/projects/freertos/]


Linux support

The mainline Linux kernel gained support for OpenRISC in version 3.1.[17] The implementation merged in this release is the 32-bit OpenRISC 1000 family (or1k).[18] Previously OpenRISC 1000 architecture, but this has now been superseded by the mainline port.


RTOS support

A number of real-time operating systems have been ported to OpenRISC, including RTEMS, FreeRTOS and eCos.


QEMU support

Since version 1.2 [19] QEMU supports emulating OpenRISC platforms.


[링크 : https://en.wikipedia.org/wiki/OpenRISC]

[링크 : http://openrisc.io/]

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