Low level program to save a mjpeg stream

Rufe0 · 06-26-2009, 03:40 AM

Hi all
Well first I’ll just say I am a complete Linux beginner, but I have done vbs, js, php, html web type stuff so I’m not a complete beginner to programming.

However I've been trying to learn C and python but it’s not making a huge amount of sense.

I am wanting to make a simple low level program that copies an image from a mjpeg stream on 192.168.0.1/videostream.cgi for example to a variable then save that variable to a file on my system.

I am aware that there are programs out there that would do this but I still want to make my own.

Any help?
Thanks Rufe0

**Fordy** · 06-26-2009, 04:57 AM

Low level...nah

You can do this with a python script

Code:

#!/usr/bin/env python

import urllib

imageUrl = "http://www.cprogramming.com/cprog.gif"
fileName = imageUrl[imageUrl.rfind("/")+1:]
imageFile = urllib.urlopen(imageUrl)

outFile = open(fileName,"wb")
outFile.write(imageFile.read())
outFile.close()
imageFile.close()

print("%s saved" % fileName)

MK27 · 06-26-2009, 11:23 AM

Get ready to say OUCH!!!

This is how I've done it in C. It is more than ten times the amount of coding as it is in python...but all the low level stuff you were just dying to see is there

ps. looks like this one uses my old header file: mine.h
pps. I bet it is faster than the python version tho

**Fordy** · 06-26-2009, 12:22 PM

Quote:

Originally Posted by MK27

Get ready to say OUCH!!!

OUCH indeed! Good effort!

Cactus_Hugger · 06-26-2009, 04:44 PM

Good work, with a few comments:
1) Single byte recv() and read()s, ouch.
2) You mix read and recv calls on a socket, why?
3) If the first byte is \n, Recept will go out of bounds on that buffer.
4 & 5 & 6) And you run that as root? (the hardcoded /root/test/... seems to say so!)
7) Doesn't answer the OP's question?

OP: You're going to need a lot of information to be able to do that. First, you have to understand HTTP. Once you get past that, you'll need to know what container format your data is going to come in (mjpeg is a video codec. Like MP3, it can be by itself, but I've never actually seen that. Usually it's packaged in something like an AVI.).

Are you sure they're streaming mjpeg? mjpeg is a terrible codec - especially over a network... 30 jpeg files / sec consumes bandwidth way quicker than most other codecs.

Rufe0 · 06-29-2009, 04:02 AM

Thanks for the replys
I am now trying to get into contact with the manufactuor who we deal with directly to see what he can do to help me. A firmware update of this device would make the program much easier to write.

gvmoney · 09-22-2009, 05:53 AM

Are you looking for a gig with C\C++ video streaming?

email: greg@infoincontext.com

Quote:

Originally Posted by Cactus_Hugger

Good work, with a few comments:
1) Single byte recv() and read()s, ouch.
2) You mix read and recv calls on a socket, why?
3) If the first byte is \n, Recept will go out of bounds on that buffer.
4 & 5 & 6) And you run that as root? (the hardcoded /root/test/... seems to say so!)
7) Doesn't answer the OP's question?

OP: You're going to need a lot of information to be able to do that. First, you have to understand HTTP. Once you get past that, you'll need to know what container format your data is going to come in (mjpeg is a video codec. Like MP3, it can be by itself, but I've never actually seen that. Usually it's packaged in something like an AVI.).

Are you sure they're streaming mjpeg? mjpeg is a terrible codec - especially over a network... 30 jpeg files / sec consumes bandwidth way quicker than most other codecs.

06-26-2009, 03:40 AM	#1
Rufe0 Registered User Join Date: Jun 2009 Posts: 2	Low level program to save a mjpeg stream Hi all Well first I’ll just say I am a complete Linux beginner, but I have done vbs, js, php, html web type stuff so I’m not a complete beginner to programming. However I've been trying to learn C and python but it’s not making a huge amount of sense. I am wanting to make a simple low level program that copies an image from a mjpeg stream on 192.168.0.1/videostream.cgi for example to a variable then save that variable to a file on my system. I am aware that there are programs out there that would do this but I still want to make my own. Any help? Thanks Rufe0
Rufe0 is offline

06-26-2009, 04:57 AM	#2
Fordy &TH of undefined behavior Join Date: Aug 2001 Posts: 5,183	Low level...nah You can do this with a python script Code: #!/usr/bin/env python import urllib imageUrl = "http://www.cprogramming.com/cprog.gif" fileName = imageUrl[imageUrl.rfind("/")+1:] imageFile = urllib.urlopen(imageUrl) outFile = open(fileName,"wb") outFile.write(imageFile.read()) outFile.close() imageFile.close() print("%s saved" % fileName) __________________ "If A is success in life, then A equals x plus y plus z. Work is x; y is play; and z is keeping your mouth shut." Albert Einstein (1879 - 1955) Board Rules
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06-26-2009, 11:23 AM	#3
MK27 subminimalist Join Date: Jul 2008 Location: NYC Posts: 3,943	Get ready to say OUCH!!! This is how I've done it in C. It is more than ten times the amount of coding as it is in python...but all the low level stuff you were just dying to see is there ps. looks like this one uses my old header file: mine.h pps. I bet it is faster than the python version tho __________________ Accuracy and integrity mean nothing if you don't make it past the censors...PYTHAGORAS Last edited by MK27; 06-26-2009 at 01:41 PM.
MK27 is online now

06-26-2009, 04:44 PM	#5
Cactus_Hugger int x = ((int ) NULL); Join Date: Jul 2003 Location: Banks of the River Styx Posts: 891	Good work, with a few comments: 1) Single byte recv() and read()s, ouch. 2) You mix read and recv calls on a socket, why? 3) If the first byte is \n, Recept will go out of bounds on that buffer. 4 & 5 & 6) And you run that as root? (the hardcoded /root/test/... seems to say so!) 7) Doesn't answer the OP's question? OP: You're going to need a lot of information to be able to do that. First, you have to understand HTTP. Once you get past that, you'll need to know what container format your data is going to come in (mjpeg is a video codec. Like MP3, it can be by itself, but I've never actually seen that. Usually it's packaged in something like an AVI.). Are you sure they're streaming mjpeg? mjpeg is a terrible codec - especially over a network... 30 jpeg files / sec consumes bandwidth way quicker than most other codecs. __________________ long time; /* know C? */ Unprecedented performance: Nothing ever ran this slow before. Any sufficiently advanced bug is indistinguishable from a feature. Real Programmers confuse Halloween and Christmas, because dec 25 == oct 31. The best way to accelerate an IBM is at 9.8 m/s/s. recursion (re - cur' - zhun) n. 1. (see recursion)
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06-29-2009, 04:02 AM	#6
Rufe0 Registered User Join Date: Jun 2009 Posts: 2	Thanks for the replys I am now trying to get into contact with the manufactuor who we deal with directly to see what he can do to help me. A firmware update of this device would make the program much easier to write. Last edited by Rufe0; 06-29-2009 at 05:52 AM.
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