Is it possible to connect an Elphel camera and display a live mjpeg stream

Hello,

[First post here, I hope I respect the rules]

I'd like to know if this would be possible with a beagle board :

- use an ethernet adapter
- connect an elphel camera (http://www.elphel.com -> open source
camera)
- have mplayer or some other player display the mjpeg stream provided
by the camera and put it full screen on video out.

The mjpeg stream provided by the camera can be any resolution, we are
targeting at full HD 24p or HD 24p (1 920 × 1 080 or 1 280 × 720)

The idea is to use the beagle board as a portable video/vga out for
the elphel.

- Do you think the Beagle board would have enough power to decode and
show this kind of
stream ?
- Is it possible to overlay some text on the video (only for status
display purpose) ?
- Is it possible to connect I2C chips to the beagle board ?
- What is the easiest/cheapest way to connect a portable, low power,
lcd screen (640*480 if possible) ?

Thank you in advance, and congratulations for this very impressive
project.

Philippe Jadin

Hi Philippe,

I'd like to know if this would be possible with a beagle board :
- use an ethernet adapter
- connect an elphel camera (http://www.elphel.com -> open source
camera)
- have mplayer or some other player display the mjpeg stream provided
by the camera and put it full screen on video out.

Certainly possible

The mjpeg stream provided by the camera can be any resolution, we are
targeting at full HD 24p or HD 24p (1 920 × 1 080 or 1 280 × 720)
- Do you think the Beagle board would have enough power to decode and
show this kind of stream ?

I doubt the 1920x1080 resolution at 24p, but I would think it's OK with the
1280x720 resolution.
Does anybody have any performance measurement on decoding JPEG on beagle?

- Is it possible to overlay some text on the video (status display

purpose) ?
No problem - You can do this in another video layer causing no CPU
performance hit

- Is it possible to connect I2C chips to the beagle board ?

No problem - On of the I2C busses is feed through to the expansion connector

Best regards - Good luck
  Søren

Hello

by the camera and put it full screen on video out.

From what I've read on http://markmail.org/message/wcyq56ivlytksc7m, I
believe the videoout resolution will be the your problem.

There's a clock limit, but I don't know how to calculate the maximum
resolution that can be achieved at a given frequency - say 60Hz

The mjpeg stream provided by the camera can be any resolution, we are
targeting at full HD 24p or HD 24p (1 920 × 1 080 or 1 280 × 720)

I've read that 1280*1024 is the maximum, but maybe something closed to
1920x1080 can be achieved (say 1680x1050).

Impossible to say without a good calculation.

- Is it possible to connect I2C chips to the beagle board ?

See the expansion port page in MUX0 mode on the SRM PDF.

- What is the easiest/cheapest way to connect a portable, low power,
lcd screen (640*480 if possible) ?

PSP screen. There're various project I'm trying to help by giving
small LCD panels, but none I know which already sells a LCD addon
board.

Guylhem Aznar <beagleboard@guylhem.net> writes:

Hello

by the camera and put it full screen on video out.

From what I've read on http://markmail.org/message/wcyq56ivlytksc7m, I
believe the videoout resolution will be the your problem.

There's a clock limit, but I don't know how to calculate the maximum
resolution that can be achieved at a given frequency - say 60Hz

The mjpeg stream provided by the camera can be any resolution, we are
targeting at full HD 24p or HD 24p (1 920 × 1 080 or 1 280 × 720)

I've read that 1280*1024 is the maximum, but maybe something closed to
1920x1080 can be achieved (say 1680x1050).

Impossible to say without a good calculation.

The Beagle board can output 720p60 and 1080p24 as well as just about
any format with a pixel clock of about 80MHz or less.

Thank you all for the detailed answers.

I doubt the 1920x1080 resolution at 24p, but I would think it's OK with the
1280x720 resolution.
Does anybody have any performance measurement on decoding JPEG on beagle?

If I provide a link to an mjpeg file can I ask someone to try to
display it using a beagle board? It doesn't need to be shown at full
scale, the final display would be on an lcd screen (like 640*480). So
the source file/stream is 1920 24p, but the display is much lower
resolution. Does it change anything for the required performances ?

> - Is it possible to overlay some text on the video (status display

purpose) ?
No problem - You can do this in another video layer causing no CPU
performance hit

What would be your advice in the choice of langage/gui tool to use? I
thought about mplayer embedded in a python script for the basic GUI
(maybe wxwindows or pyGTK ?). Sorry if it has been asked before, but
what is the recommended environnement for beagle board applications
development with very little code and UI, and fast video playback ?

Philippe Jadin <philippe.jadin@gmail.com> writes:

Thank you all for the detailed answers.

I doubt the 1920x1080 resolution at 24p, but I would think it's OK with the
1280x720 resolution.
Does anybody have any performance measurement on decoding JPEG on beagle?

If I provide a link to an mjpeg file can I ask someone to try to
display it using a beagle board? It doesn't need to be shown at full
scale, the final display would be on an lcd screen (like 640*480). So
the source file/stream is 1920 24p, but the display is much lower
resolution. Does it change anything for the required performances ?

Please post a link. I'm always interested in samples.

> If I provide a link to an mjpeg file can I ask someone to try to
> display it using a beagle board? It doesn't need to be shown at full
> scale, the final display would be on an lcd screen (like 640*480). So
> the source file/stream is 1920 24p, but the display is much lower
> resolution. Does it change anything for the required performances ?

Please post a link. I'm always interested in samples.

Thank you very much.

Here is a link to a full hd mjpeg sample :
http://community.elphel.com/videos/snow_HD.mov

There are a lot of other samples here : http://community.elphel.com/videos/